Skip Navigation



Briefings in Functional Genomics Advance Access published online on January 21, 2008
Briefings in Functional Genomics, doi:10.1093/bfgp/elm037
This Article
Right arrow Abstract Freely available
Right arrow FREE Full Text (PDF) Freely available
Right arrow All Versions of this Article:
7/1/8    most recent
elm037v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Google Scholar
Right arrow Articles by Scott, G. B.
Right arrow Articles by Cook, G. P.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Scott, G. B.
Right arrow Articles by Cook, G. P.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

© Oxford University Press, 2008, All rights reserved. For permissions, please email: journals.permissions@oxfordjournals.org

Profiling killers; unravelling the pathways of human natural killer cell function

Gina B. Scott, Josephine L. Meade and Graham P. Cook

Corresponding author. Graham P. Cook, Leeds Institute of Molecular Medicine, University of Leeds, Wellcome Trust Brenner Building, St James's University Hospital, Leeds LS9 7TF, UK. Tel: +113 343 8411; Fax: +113 343 8501; E-mail: g.p.cook{at}leeds.ac.uk


   ABSTRACT
TOP
 ABSTRACT
INTRODUCTION
 IDENTIFICATION OF NK CELL...
 IDENTIFICATION OF NK CELL...
 GLOBAL APPROACHES
 CYTOTOXIC FUNCTION AND INDUCING...
 ACKNOWLEDGEMENTS
 REFERENCES
 
Natural killer (NK) cells are lymphocytes with an innate ability to recognize and kill infected cells and tumour cells. Unlike B and T cells, NK cells do not express an antigen receptor. Instead, NK cells detect changes in the phenotype of the target cell surface; malignant transformation or infection resulting in the loss or gain of particular molecules that are detected by inhibitory or activating receptors on the NK cell surface. The identification and characterization of NK cells and their receptors was made possible by monoclonal antibody technology. The ease with which genes and gene products can now be identified and manipulated has accelerated our understanding of NK cell function. Furthermore, gene and protein profiling studies are beginning to refine our understanding of NK cells, their interactions with other cells and their effector mechanisms. This review illustrates some of the basic features of NK cell biology and highlights the contribution made by post-genomic technology in defining the molecular mechanisms by which NK cells identify and kill susceptible targets.

Keywords: NK cells, immune response, protease, granzyme, protease substrate


   INTRODUCTION
TOP
 ABSTRACT
 INTRODUCTION
IDENTIFICATION OF NK CELL...
 IDENTIFICATION OF NK CELL...
 GLOBAL APPROACHES
 CYTOTOXIC FUNCTION AND INDUCING...
 ACKNOWLEDGEMENTS
 REFERENCES
 
Natural killer (NK) cells are lymphocytes with an innate ability to seek out and destroy infected cells and malignant cells [1, 2]. The B and T lymphocyte populations perform these functions via expression of B and T cell antigen receptors. However, NK cells do not express antigen receptors but rely instead upon an array of cell surface receptors to detect changes in expression of host cell surface molecules that are indicative of intracellular infection or malignant transformation [1, 2]. The decision to kill is made based on the net balance of signals delivered by inhibitory and activating receptor molecules. For example, many viruses such as members of the Herpes and Adenovirus family reduce the cell surface expression of Major Histocompatibility Complex (MHC) class I molecules during infection [3] and tumour cells frequently lose expression of MHC class I molecules during malignant progression [4]. This allows infected cells or tumour cells to escape the attention of cytotoxic T cells. However, NK cells express Killer Inhibitory Receptor (KIR) molecules that recognize MHC class I. Loss of MHC class I on the target cell surface thus results in a failure to deliver these inhibitory signals and the NK cell is activated [1, 2]. Activation signals on the target cell include the stress inducible ligands of the NK cell activation receptor NKG2D [5]. Infection can induce the expression of NKG2D ligands via the activation of Toll-Like receptors [6]. In addition, DNA damage and signalling via the ATM pathway has been shown to induce NKG2D ligand expression, thus coupling DNA damage to immune activation [7]. Numerous NK cell activation receptors have been identified and several ligands have also been characterized [1, 2].


   IDENTIFICATION OF NK CELL RECEPTORS
TOP
 ABSTRACT
 INTRODUCTION
 IDENTIFICATION OF NK CELL...
IDENTIFICATION OF NK CELL...
 GLOBAL APPROACHES
 CYTOTOXIC FUNCTION AND INDUCING...
 ACKNOWLEDGEMENTS
 REFERENCES
 
If a single technique had to be identified as making the major contribution towards understanding NK cells, it would probably be the ability to make monoclonal antibodies against cell surface antigens, the so-called cluster of differentiation (CD) antigens [8]. NK cell receptor molecules were initially defined as surface antigens in the rat and mouse [9]. Many CD antigens have been defined on NK cells of mouse, rat and human, allowing the identification and characterization of the corresponding gene product, either via expression cloning used, for example, to identify the CD94 and NKp30 molecules [10, 11], or via affinity purification of the antigen and protein sequencing, as used to identify DNAX Accessory Molecule (DNAM)-1 [12]. Following the identification of prototype receptors, it became possible to identify related molecules using bioinformatics approaches and genome-based technologies. For example, several NK cell receptors are type II transmembrane molecules belonging to the C-type lectin superfamily, and are encoded by the NK cell receptor gene complex on mouse chromosome 6 and human chromosome 12. Searching EST databases, coupled with cDNA cloning and genomic contig mapping allowed numerous NK cell receptor genes to be identified, sometimes using cross-species approaches [13–16].


   IDENTIFICATION OF NK CELL RECEPTOR LIGANDS
TOP
 ABSTRACT
 INTRODUCTION
 IDENTIFICATION OF NK CELL...
 IDENTIFICATION OF NK CELL...
GLOBAL APPROACHES
 CYTOTOXIC FUNCTION AND INDUCING...
 ACKNOWLEDGEMENTS
 REFERENCES
 
The binding of NKG2D to MHC class I related stress inducible ligands emerged from a study to define a receptor for the MHC class I chain-related gene product, MICA [17]. Recombinant soluble MICA (sMICA) and flow cytometry were used to identify cells that bound to sMICA (and hence expressed a receptor). Cells that bound to sMICA included most {gamma}{delta} T cells, CD8+ T cells and NK cells, but relatively low numbers of CD4+ T cells. Representational difference analysis (RDA) was then used to compare mRNA species in CD4+ T cells classified (using sMICA flow cytometry) as either receptor expressing or non-expressing. After multiple rounds of RDA, a single transcript predominated that encoded the NK cell receptor NKG2D. Transfection of NKG2D was sufficient to confer sMICA binding on cells that did not normally bind to this molecule and the monoclonal antibodies that blocked sMICA binding were found to be specific for NKG2D [17]. Other NKG2D ligands were identified during a study of an open reading frame (UL16) from human cytomegalovirus (HCMV), which was proposed to possess immune evasion activity. Using an expression cloning strategy, soluble UL16 was found to interact with a family of molecules that included MICB (related to MICA, already shown to interact with NKG2D) and several glycosylphosphatidylinositol (GPI)-linked molecules with extracellular domains related to MICA [18]. Like MICA, UL16 binding proteins (ULBPs) bind directly to NKG2D. This study thus identified a family of NKG2D ligands and importantly led to the discovery that the HCMV UL16 reduced the cell surface expression of NKG2D ligands, thus allowing HCMV infected cells to evade NK cell mediated attack [19]. Additional ligands of NKG2D have been identified using bioinformatics-based approaches and the prototype sequences of MICA, MICB and the ULBPs [20].

The NKG2D molecule binds to ligands that are strongly induced in infected or malignant cells. However, healthy cells also express ligands of NK cell activating receptors. For example, the ligands of DNAM-1 were identified using monoclonal antibodies that blocked NK cell activation [21]. These antibodies were then used to affinity purify the corresponding antigens from membrane fractions. The purified proteins were then partially sequenced using mass spectrometry and found to correspond to the poliovirus receptor (PVR/CD155) and Nectin-2 (CD112). This analysis identified the antigens but not their cognate receptor on NK cells. This was performed by generating secreted fusion proteins of the extracellular domains of PVR and Nectin-2 fused to an immunoglobulin constant region. These reagents were then used like antibodies to identify their corresponding receptor on NK cells using a candidate approach. The fusion proteins were used to stain COS-7 cells transiently transfected with NK cell activation receptors. Whilst the natural cytotoxicity receptor (NCR) molecules NKp30 and NKp46 were excluded as receptors for these molecules, both PVR and Nectin-2 were found to bind to the DNAM-1 molecule [21]. Thus, both DNAM-1 and its cognate ligands were identified using monoclonal antibodies that blocked the function of cytotoxic lymphocytes [12, 21]. Both Nectin-2 and PVR are expressed by healthy cells [22, 23]. Despite this, DNAM-1 has been shown to play an important role in the NK cell-mediated killing of numerous tumour-derived cell lines as well as tumour cells derived from patients [12, 21, 24–27]. Thus, DNAM-1 is unlikely to be a ‘decision-making’ receptor but supplies an accessory role in NK cell activation (such as cell adhesion). Interestingly, PVR has been shown to be inducible by RAS signalling pathways and control proliferation in RAS transformed cells [28]. Thus, tumour cells with mutant RAS may have increased PVR expression and thus be more susceptible to NK cell lysis, especially if this occurs in cells in which cell surface MHC class I expression is reduced. However, this remains untested. A role for DNAM-1 in tumour immune surveillance in vivo has been elegantly demonstrated by showing that tumour cells expressing DNAM-1 ligands were more readily rejected than matched cells lacking DNAM-1 ligands and that this rejection was mediated by both NK and T cells [29]. The importance of DNAM-1 in mediating NK cell responses to viral infection is highlighted by the HCMV gene, UL141, whose product blocks the expression of PVR at the infected cell surface and prevents NK cell recognition and killing [30]. In fact, HCMV encodes multiple proteins that mediate evasion from NK cells [31]. In addition, HCMV encodes at least one microRNA (miR-UL112) that reduces expression of the NKG2D ligand MICB at the infected cell surface and inhibits NK cell-mediated killing [32]. Studying the HCMV genome, including clinical isolates as well as common laboratory strains, has proved to be extremely fruitful in understanding the mechanisms by which NK cells recognize their targets.

One of the most remarkable applications of post-genomic technologies in the NK cell field has emerged from the identification of ligands for the NK cell receptor NKRP1. NKRP1 molecules are encoded by a multigene family in the mouse but a single gene in humans. Iizuka et al. [33] used a system originally developed for the identification of T cell receptor ligands. Reporter cell lines were constructed in which the extracellular domain of mouse NKRP1 was fused via a transmembrane domain to a cytoplasmic tail with potent signalling activity. Ligation of this chimaeric receptor leads to signal transduction via the cytoplasmic tail and induction of a lacZ gene. A battery of cell lines was shown to express ligands by activating lacZ in the reporter cell line. Soluble NKRP1 tetramer molecules showed a similar pattern of binding to the cell lines, validating the results from the lacZ reporter cell line. The NKRP1 tetramers were then used in an expression cloning strategy using mRNA prepared from the cell lines shown to express NKRP1 ligands by both the lacZ reporter strategy and the tetramers. The mouse NKRP1 ligands were identified as members of the C-type lectin-related (Clr) gene family. The Clr gene family is related to the NKRP1 family and the NKRP1 and Clr genes are interspersed with each other in the mouse NK cell gene complex [33]. Furthermore, expression cloning showed that human NKRP1 bound to LLT1 (lectin-like transcript 1), a ligand encoded by a gene in the human NK cell gene complex [34, 35]. This theme of linked genes encoding receptor–ligand pairs in the NK cell gene complex is also found with the human NK cell receptor NKp80 and AICL (activation-induced C-type lectin, expressed by activated leucocytes) [36]. The linkage of receptor–ligand pairs presumably reflects evolutionary events, which allow coordinated cellular interactions within the immune system [33, 36].

Despite the success of post-genomic technology in identifying ligands of NK cell receptors, one set of receptor ligands has been elusive. In humans, NK cell cytotoxicity is potently activated by the natural cytotoxicity receptors (NCRs) NKp30, NKp44 and NKp46 [1, 2]. A single NCR molecule has been identified in the mouse (NCR1). Human NKp44 and NKp46 can bind directly to viral haemagglutinin molecules [37, 38] and NCR1 knock-out mice are highly susceptible to influenza virus infection [39]. This indicates that NK cells can recognize virus infected cells directly and places these NCR molecules in the family of pathogen pattern receptor molecules characteristic of innate immunity. In addition, the HCMV protein pp65 (UL83) interacts with NKp30 and blocks its activity, mediating NK cell evasion [40]. Experiments with blocking antibodies indicate that the NCR molecules are important in the NK cell-mediated killing of tumour cells implying the existence of cellular ligands. However, these remain somewhat elusive. It has been shown that NKp30 and NKp46 recognize heparan sulphate structures on target cells [41]. However, binding of NKp30 to these structures was not supported in a separate study [42]. It has been suggested that this discrepancy is due to the fact that the different recombinant NKp30 molecules used in these studies have different patterns of glycosylation and that this affects binding to heparan sulphate [43]. Two studies have identified proteins that normally reside within cells as potential NCR ligands; the intermediate filament protein vimentin as an NKp46 binding protein [44] and the nuclear factor BAT3 as an NKp30 interacting partner [45]. Under certain conditions, these NCR interacting proteins could be found at the cell surface or were released from cells, and both were demonstrated to play a role in NK cell cytotoxicity. Many issues remain unresolved, such as why and how these normally intracellular proteins become visible to a cell surface receptor. However, the HCMV pp65 (UL83) protein, which binds to NKp46, also has an intracellular localization and has been proposed to interact with NKp46 following cell lysis [31, 40]. Thus, NCR molecules may detect damaged cells. Interestingly, certain intracellular molecules (such as the high mobility group box 1 protein, HMGB1) when released as a result of cell damage, can activate immune responses [46, 47]. The importance of identifying NCR ligands is further emphasized by evidence which suggests that, as well as being important in regulating NK cell activation by tumour cells or infected cells, NKp30 plays a role in the interaction between NK cells and healthy dendritic cells during an immune response [48, 49].


   GLOBAL APPROACHES
TOP
 ABSTRACT
 INTRODUCTION
 IDENTIFICATION OF NK CELL...
 IDENTIFICATION OF NK CELL...
 GLOBAL APPROACHES
CYTOTOXIC FUNCTION AND INDUCING...
 ACKNOWLEDGEMENTS
 REFERENCES
 
Our knowledge of the NK cell surface comes largely from the focused studies described earlier in which individual cell surface molecules (and their ligands) have been identified. Global approaches have also been used to identify proteins present on the NK cell surface. For example, proteomic studies have been used to identify proteins on membrane fractions of NK cells [50–54]. New features of NK cell biology have been identified from these studies. Comparison of proteins present on resting and activated NK cells indicated upregulation of MHC class II and co-stimulatory molecules following NK cell activation [53], in agreement with microarray work from the same laboratory [55]. These molecules are normally found on the surface of professional antigen presenting cells such as dendritic cells or B-cells and present endocytosed antigen to CD4+ T cells. Functional studies confirmed that NK cells could not only kill target cells, but endocytose antigen and present them to CD4+ T cells, eliciting T cell responses [53]. These results imply a hitherto unknown function of NK cells, that of antigen presentation. The expression of MHC class II molecules by activated NK cells had been known for many years [56], but its functional significance was not known.

NK cells in human peripheral blood are classified into two principal subsets based on the expression of the CD56 antigen [57]; 90% of NK cells have a CD56dim phenotype and are believed to be the major cytotoxic population, whilst 10% have a CD56bright phenotype and are major producers of interferon (IFN)-{gamma} following stimulation with monokines such as IL-12 [57, 58]. However, CD56dim NK cells can preferentially produce IFN-{gamma} in response to tumour targets [59]. Gene expression analysis revealed that the SET gene was upregulated in monokine stimulated NK cells [60]. Furthermore, SET was highly expressed in the CD56bright population. Functional studies confirmed that upregulation of SET protein was associated with increased IFN-{gamma} production and that SET inhibited protein phosphatase type 2A (PP2A); PP2A inhibits transcription factors required for IFN-{gamma} expression and, by antagonizing PP2A, SET allows IFN-{gamma} expression [60]. Microarray-based studies have been used to compare the gene expression profiles in CD56dim and CD56bright NK cells [55, 61]. These studies have provided clues to the differences in cytotoxic activity and tissue distribution of the different NK cell subsets as well as hints as to how NK cells might interact with other immune cell types.

A third population of NK cells exists in the decidua, the tissue at the interface between the mother and the developing fetus. These NK cells have a CD56bright cell surface phenotype and are important in allowing the invasion of the foetal tissue into maternal tissue (representing a mixing of mismatched tissue types). Microarray studies revealed that the decidual NK cells are very different to either peripheral blood-derived NK cell subset [62]. This raised the possibility that decidual NK cells represent a distinct lineage. However, it was subsequently shown that TGF-β (which is produced by decidual stromal cells) could promote the in vitro differentiation of CD56dim NK cells into cells with a phenotype resembling decidual NK cells [63].

Post-genomic technology will no doubt advance our definition and understanding of NK cell subsets beyond simple cell surface phenotypes towards molecular profiles of different subsets. This will provide both phenotypic and functional information. Cell surface expression of NKp46 is a defining feature of NK cells from multiple species, unlike CD56 or other species-specific markers [64]. By defining genes with a similar pattern of expression to NKp46, Walzer et al. [65] identified a ‘transcriptional signature’ of human NK cells comprising 79 expressed genes. The signature included genes that could be predicted, such as NK cell receptors and cytotoxic effector molecules, as well as cytokines, chemokines, signalling molecules, transcription factors and a host of genes with, as yet, unknown function. The application of global profiling approaches will no doubt continue to enhance of our understanding of NK cells and the mechanisms by which they function in the immune response.


   CYTOTOXIC FUNCTION AND INDUCING APOPTOSIS
TOP
 ABSTRACT
 INTRODUCTION
 IDENTIFICATION OF NK CELL...
 IDENTIFICATION OF NK CELL...
 GLOBAL APPROACHES
 CYTOTOXIC FUNCTION AND INDUCING...
ACKNOWLEDGEMENTS
 REFERENCES
 
NK cells kill their targets via the induction of apoptosis. This is achieved using one of two pathways; the ligation of death receptors (such as Fas, TRAILR or TNF{alpha}R) on the target cell surface or via the granule exocytosis pathway [66]. This latter pathway is believed to play the dominant role in target cell killing. The NK cell, like cytotoxic (CD8+) T cells, contains cytotoxic granules. These granules are secretory lysosomes, capable of efficient fusion with the plasmamembrane and exocytosis of their contents.

Proteomic analysis of the NK cell cytotoxic granule revealed the identity of proteins associated with the granule membrane [54]. These proteins include pro-apoptotic molecules, molecules regulating the killing machinery as well as proteins involved in the exocytosis pathway itself. This study provides a platform for future investigation of the NK cell cytotoxic function as well as highlighting the relationship between NK cell exocytosis and related events in other, non-immune cell types [54]. The granules contain the pro-apoptotic serine protease molecules granzymes A, B, H, K and M as well as the perforin molecule. Upon exocytosis, perforin allows the granzyme molecules to access the target cell cytoplasm and other organelles where, via protease cleavage events, they stimulate the induction of apoptosis.

Granzyme B is the most intensively studied granzyme molecule and has aspartase (aspase) activity, similar to members of the caspase family [67, 68]. Granzyme B can cleave pro-caspases and trigger the apoptotic pathway. In addition, granzyme B can rapidly cleave the pro-apoptotic molecule Bid to a truncated form tBid; tBid then translocates from the cytoplasm to the mitochondrial membrane where it induces the release of pro-apoptotic molecules from the mitochondria and amplifies the apoptotic pathway [67, 68]. Following the definition of aspase activity [67, 68], the refined substrate specificity of granzyme B was determined using libraries of synthetic substrates and phage display technology that allowed phage to be released from a column only when a synthetic granzyme B site was cleaved [69]. Definition of a consensus sequence for granzyme B cleavage has allowed the design of software, which can predict potential granzyme B (and caspase) cleavage sites in individual proteins [70]. Granzyme B cleaves Bid in an exposed loop and database searches of sequences related to this Bid loop identified a granzyme B cleavage site in the Hsc70 interacting protein HIP and functional studies suggest that HIP has anti-apoptotic activity which is counteracted by granzyme B cleavage [71].

A number of proteomic approaches have been developed, which do not require prior knowledge of the substrate specificity and which are applicable to any protease molecule. Comparison of untreated lysates and protease treated lysates by one-dimensional SDS-PAGE [72] or 2D gel electrophoresis [73] allows potential substrates to be revealed and subsequently identified by mass spectrometry. These conceptually simple approaches have identified {alpha}-tubulin as a granzyme B substrate [72, 73]. Two-dimensional difference gel electrophoresis (2D-DIGE) has also been used. Bredermeyer et al. [74] labelled untreated cell lysates with the fluorecescent dye Cy3 (green) and granzyme B treated lysates with Cy5 (red). Most proteins are unaffected by protease digestion and are present with both red and green labels (and appear yellow on overlaid images), whereas new cleavage products appear red (and leave a green-labelled species without a red-labelled partner). These experiments revealed the known granzyme B substrate caspase-3 and identified new substrates including the chaperone protein HOP (Hsp70/Hsp90-organizing protein). The ability of granzyme B to cleave chaperone molecules (HIP, HOP and others) suggests that granzyme B induced apoptosis may inactivate normal stress responses [75, 76]. This study also highlights some important general features of analysis of protease cleavage sites. First, the number of granzyme B targets detected was very low in comparison to the number predicted from the frequency of the consensus sequence in the databases. This indicates that the presence of a consensus sequence alone is insufficient and that interactions between the protease and the correctly folded and displayed substrate are important for determining cleavage. Second, granzyme B activates caspases and some cleavage products were only detected in the absence of caspase inhibitors indicating that they are not direct targets of granzyme B cleavage. Direct cleavage by granzyme B can only be ascertained using recombinant granzyme B and purified candidate molecules [74]. The importance of caspases in mediating the apoptotic response to granzyme B was highlighted in another study using conventional 2D gel electrophoresis. Comparison of protein spots obtained from granzyme B treated lysates and granzyme B treated lysates depleted of either caspase-3 or caspase-7 indicated that the majority of granzyme B-mediated cleavage events occurred via activation of caspase-3 [77]. One note of caution, it is tempting to extrapolate findings in one mammalian species with another. However, analysis of the substrate specificities of mouse and human granzyme molecules has indicated that the two enzymes have different specificities and that apoptosis induction via mouse and human granzyme B may have different requirements for Bid cleavage [78–80].

Studies to identify protease substrates using cell lysates and gel-based approaches are limited by factors such as protein abundance, extraction and gel mobility. In an alternative approach, Loeb et al. [81] used cDNA as a starting material for screening. A cDNA library (~200 000 clones) was sub-divided into pools of 100 clones and the pools transcribed and translated in vitro. Radiolabelled proteins were then incubated with or without granzyme B and run on SDS-PAGE. Pools showing evidence of cleavage were then further subdivided until individual cDNA clones were identified. This approach identified cleavage sites within the cytoplasmic tail of cell surface receptor molecules Notch1 and FGFR1, which would not be expected to be easily identified using cell lysates. These results suggest that granzyme B cleavage may halt proliferation of target cells by interfering with receptor signalling, revealing a new facet of granzyme-mediated cell death. The utility of this technique was proven nearly a decade before whilst identifying caspase substrates [82, 83]. Covalent coupling of mRNA to its protein product enabled Ju et al. [84] to identify novel caspase substrates. In this technique, mRNA is synthesized with a puromycin tag that links the mRNA to the encoded protein. The protein is biotinylated at the C-terminus allowing the protein–nucleic acid conjugate to be held on a column. Treatment with a protease then releases the nucleic acid and residual protein if a cleavage site is present. Eluted nucleic acid is amplified and the process can be repeated. Using this technique, a number of caspase substrates were identified and the authors reported that a similar screen has been performed to identify granzyme B substrates [84], although these studies were not detailed. Human NK cells express granzymes A, B, H, K and M. Granzyme A has a number of well characterized substrates [85–87] and data is emerging on the substrates of other granzyme molecules [88–91]. Application of these technologies will no doubt uncover new substrates and provide insight into the mechanisms of granzyme-mediated apoptosis.


   ACKNOWLEDGEMENTS
TOP
 ABSTRACT
 INTRODUCTION
 IDENTIFICATION OF NK CELL...
 IDENTIFICATION OF NK CELL...
 GLOBAL APPROACHES
 CYTOTOXIC FUNCTION AND INDUCING...
 ACKNOWLEDGEMENTS
REFERENCES
 
We are grateful to those authors who provided us with information prior to publication. NK cell research in our laboratory has been generously supported by the Wellcome Trust, Yorkshire Cancer Research and Candlelighter's.


   FOOTNOTES
 
Gina Scott and Josephine Meade are Senior Post-Doctoral Fellows.

Graham Cook is Head of the Immunology Laboratory, Leeds Institute of Molecular Medicine.


   REFERENCES
TOP
 ABSTRACT
 INTRODUCTION
 IDENTIFICATION OF NK CELL...
 IDENTIFICATION OF NK CELL...
 GLOBAL APPROACHES
 CYTOTOXIC FUNCTION AND INDUCING...
 ACKNOWLEDGEMENTS
 REFERENCES
 

  1. Lanier LL. NK cell recognition. Annu Rev Immunol (2005) 23:225–74.[CrossRef][Web of Science][Medline]
  2. Moretta L, Moretta A. Unravelling natural killer cell function: triggering and inhibitory human NK receptors. EMBO J (2004) 23:255–59.[CrossRef][Web of Science][Medline]
  3. Hewitt EW. The MHC class I antigen presentation pathway: strategies for viral immune evasion. Immunology (2003) 110:163–69.[CrossRef][Web of Science][Medline]
  4. Aptsiauri N, Cabrera T, Mendez R, et al. Role of altered expression of HLA class I molecules in cancer progression. Adv Exp Med Biol (2007) 601:123–31.[Web of Science][Medline]
  5. Raulet DH. Roles of the NKG2D immunoreceptor and its ligands. Nat Rev Immunol (2003) 3:781–90.[CrossRef][Web of Science][Medline]
  6. Hamerman JA, Ogasawara K, Lanier LL. Cutting edge: toll-like receptor signaling in macrophages induces ligands for the NKG2D receptor. J Immunol (2004) 172:2001–5.[Abstract/Free Full Text]
  7. Gasser S, Orsulic S, Brown EJ, et al. The DNA damage pathway regulates innate immune system ligands of the NKG2D receptor. Nature (2005) 436:1186–90.[CrossRef][Medline]
  8. Milstein C. The hybridoma revolution: an offshoot of basic research. Bioessays (1999) 21:966–73.[CrossRef][Web of Science][Medline]
  9. Yokoyama WM, Seaman WE. The Ly-49 and NKR-P1 gene families encoding lectin-like receptors on natural killer cells: the NK gene complex. Annu Rev Immunol (1993) 11:613–35.[Web of Science][Medline]
  10. Chang C, Rodriguez A, Carretero M, et al. Molecular characterization of human CD94: a type II membrane glycoprotein related to the C-type lectin superfamily. Eur J Immunol (1995) 25:2433–7.[Web of Science][Medline]
  11. Pende D, Parolini S, Pessino A, et al. Identification and molecular characterization of NKp30, a novel triggering receptor involved in natural cytotoxicity mediated by human natural killer cells. J Exp Med (1999) 190:1505–16.[Abstract/Free Full Text]
  12. Shibuya A, Campbell D, Hannum C, et al. DNAM-1, a novel adhesion molecule involved in the cytolytic function of T lymphocytes. Immunity (1996) 4:573–81.[CrossRef][Web of Science][Medline]
  13. Vance RE, Tanamachi DM, Hanke T, et al. Cloning of a mouse homolog of CD94 extends the family of C-type lectins on murine natural killer cells. Eur J Immunol (1997) 27:3236–41.[Web of Science][Medline]
  14. Ho EL, Heusel JW, Brown MG, et al. Murine Nkg2d and Cd94 are clustered within the natural killer complex and are expressed independently in natural killer cells. Proc Natl Acad Sci USA (1998) 95:6320–5.[Abstract/Free Full Text]
  15. Hanke T, Corral L, Vance RE, et al. 2F1 antigen, the mouse homolog of the rat "mast cell function-associated antigen", is a lectin-like type II transmembrane receptor expressed by natural killer cells. Eur J Immunol (1998) 28:4409–17.[CrossRef][Web of Science][Medline]
  16. Butcher S, Arney KL, Cook GP. MAFA-L, an ITIM-containing receptor encoded by the human NK cell gene complex and expressed by basophils and NK cells. Eur J Immunol (1998) 28:3755–62.[CrossRef][Web of Science][Medline]
  17. Bauer S, Groh V, Wu J, et al. Activation of NK cells and T cells by NKG2D, a receptor for stress-inducible MICA. Science (1999) 285:727–9.[Abstract/Free Full Text]
  18. Cosman D, Mullberg J, Sutherland CL, et al. ULBPs, novel MHC class I-related molecules, bind to CMV glycoprotein UL16 and stimulate NK cytotoxicity through the NKG2D receptor. Immunity (2001) 14:123–33.[CrossRef][Web of Science][Medline]
  19. Dunn C, Chalupny NJ, Sutherland CL, et al. Human cytomegalovirus glycoprotein UL16 causes intracellular sequestration of NKG2D ligands, protecting against natural killer cell cytotoxicity. J Exp Med (2003) 197:1427–39.[Abstract/Free Full Text]
  20. Eagle RA, Trowsdale J. Promiscuity and the single receptor: NKG2D. Nat Rev Immunol (2007) 7:737–44.[CrossRef][Web of Science][Medline]
  21. Bottino C, Castriconi R, Pende D, et al. Identification of PVR (CD155) and Nectin-2 (CD112) as cell surface ligands for the human DNAM-1 (CD226) activating molecule. J Exp Med (2003) 198:557–67.[Abstract/Free Full Text]
  22. Fuchs A, Colonna M. The role of NK cell recognition of nectin and nectin-like proteins in tumor immunosurveillance. Semin Cancer Biol (2006) 16:359–66.[CrossRef][Web of Science][Medline]
  23. Baury B, Masson D, McDermott BM Jr, et al. Identification of secreted CD155 isoforms. Biochem Biophys Res Commun (2003) 309:175–82.[CrossRef][Web of Science][Medline]
  24. Castriconi R, Dondero A, Corrias MV, et al. Natural killer cell-mediated killing of freshly isolated neuroblastoma cells: critical role of DNAX accessory molecule-1-poliovirus receptor interaction. Cancer Res (2004) 64:9180–4.[Abstract/Free Full Text]
  25. Carlsten M, Bjorkstrom NK, Norell H, et al. DNAX accessory molecule-1 mediated recognition of freshly isolated ovarian carcinoma by resting natural killer cells. Cancer Res (2007) 67:1317–25.[Abstract/Free Full Text]
  26. Pende D, Spaggiari GM, Marcenaro S, et al. Analysis of the receptor-ligand interactions in the natural killer-mediated lysis of freshly isolated myeloid or lymphoblastic leukemias: evidence for the involvement of the Poliovirus receptor (CD155) and Nectin-2 (CD112). Blood (2005) 105:2066–73.[Abstract/Free Full Text]
  27. El-Sherbiny YM, Meade JL, Holmes TD, et al. The requirement for DNAM-1, NKG2D, and NKp46 in the natural killer cell-mediated killing of myeloma cells. Cancer Res (2007) 67:8444–9.[Abstract/Free Full Text]
  28. Kono T, Imai Y, Yasuda SI, et al. The CD155/poliovirus receptor enhances the proliferation of ras-mutated cells. Int J Cancer (2007) 122:317–24.[CrossRef][Web of Science]
  29. Tahara-Hanaoka S, Shibuya K, Kai H, et al. Tumor rejection by the poliovirus receptor family ligands of the DNAM-1 (CD226) receptor. Blood (2006) 107:1491–6.[Abstract/Free Full Text]
  30. Tomasec P, Wang EC, Davison AJ, et al. Downregulation of natural killer cell-activating ligand CD155 by human cytomegalovirus UL141. Nat Immunol (2005) 6:181–8.[CrossRef][Web of Science][Medline]
  31. Wilkinson GW, Tomasec P, Stanton RJ, et al. Modulation of natural killer cells by human cytomegalovirus. J Clin Virol (2008;) doi:10.1016/j.jcv.2007.10.027.
  32. Stern-Ginossar N, Elefant N, Zimmermann A, et al. Host immune system gene targeting by a viral miRNA. Science (2007) 317:376–81.[Abstract/Free Full Text]
  33. Iizuka K, Naidenko OV, Plougastel BF, et al. Genetically linked C-type lectin-related ligands for the NKRP1 family of natural killer cell receptors. Nat Immunol (2003) 4:801–7.[CrossRef][Web of Science][Medline]
  34. Rosen DB, Bettadapura J, Alsharifi M, et al. Cutting edge: lectin-like transcript-1 is a ligand for the inhibitory human NKR-P1A receptor. J Immunol (2005) 175:7796–9.[Abstract/Free Full Text]
  35. Aldemir H, Prod'homme V, Dumaurier MJ, et al. Cutting edge: lectin-like transcript 1 is a ligand for the CD161 receptor. J Immunol (2005) 175:7791–5.[Abstract/Free Full Text]
  36. Welte S, Kuttruff S, Waldhauer I, et al. Mutual activation of natural killer cells and monocytes mediated by NKp80-AICL interaction. Nat Immunol (2006) 7:1334–42.[CrossRef][Web of Science][Medline]
  37. Arnon TI, Lev M, Katz G, et al. Recognition of viral hemagglutinins by NKp44 but not by NKp30. Eur J Immunol (2001) 31:2680–9.[CrossRef][Web of Science][Medline]
  38. Mandelboim O, Lieberman N, Lev M, et al. Recognition of haemagglutinins on virus-infected cells by NKp46 activates lysis by human NK cells. Nature (2001) 409:1055–60.[CrossRef][Medline]
  39. Gazit R, Gruda R, Elboim M, et al. Lethal influenza infection in the absence of the natural killer cell receptor gene Ncr1. Nat Immunol (2006) 7:517–23.[CrossRef][Web of Science][Medline]
  40. Arnon TI, Achdout H, Levi O, et al. Inhibition of the NKp30 activating receptor by pp65 of human cytomegalovirus. Nat Immunol (2005) 6:515–23.[CrossRef][Web of Science][Medline]
  41. Bloushtain N, Qimron U, Bar-Ilan A, et al. Membrane-associated heparan sulfate proteoglycans are involved in the recognition of cellular targets by NKp30 and NKp46. J Immunol (2004) 173:2392–401.[Abstract/Free Full Text]
  42. Warren HS, Jones AL, Freeman C, et al. Evidence that the cellular ligand for the human NK cell activation receptor NKp30 is not a heparan sulfate glycosaminoglycan. J Immunol (2005) 175:207–12.[Abstract/Free Full Text]
  43. Hershkovitz O, Jarahian M, Zilka A, et al. Altered glycosylation of recombinant NKp30 hampers binding to heparan sulfate: a lesson for the use of recombinant immuno-receptors as an immunological tool. Glycobiology (2008) 18:28–41.[Abstract/Free Full Text]
  44. Garg A, Barnes PF, Porgador A, et al. Vimentin expressed on Mycobacterium tuberculosis-infected human monocytes is involved in binding to the NKp46 receptor. J Immunol (2006) 177:6192–8.[Abstract/Free Full Text]
  45. Pogge von Strandmann E, Simhadri VR, von Tresckow B, et al. Human leukocyte antigen-B-associated transcript 3 is released from tumor cells and engages the NKp30 receptor on natural killer cells. Immunity (2007) 27:965–74.[CrossRef][Medline]
  46. Dumitriu IE, Baruah P, Manfredi AA, et al. HMGB1: guiding immunity from within. Trends Immunol (2005) 26:381–7.[CrossRef][Web of Science][Medline]
  47. Bianchi ME. DAMPs, PAMPs and alarmins: all we need to know about danger. J Leukoc Biol (2007) 81:1–5.[Abstract/Free Full Text]
  48. Ferlazzo G, Tsang ML, Moretta L, et al. Human dendritic cells activate resting natural killer (NK) cells and are recognized via the NKp30 receptor by activated NK cells. J Exp Med (2002) 195:343–51.[Abstract/Free Full Text]
  49. Vitale M, Della Chiesa M, Carlomagno S, et al. NK-dependent DC maturation is mediated by TNFalpha and IFNgamma released upon engagement of the NKp30 triggering receptor. Blood (2005) 106:566–71.[Abstract/Free Full Text]
  50. Lund TC, Anderson LB, McCullar V, et al. iTRAQ is a useful method to screen for membrane-bound proteins differentially expressed in human natural killer cell types. J Proteome Res (2007) 6:644–53.[CrossRef][Web of Science][Medline]
  51. Man P, Novak P, Cebecauer M, et al. Mass spectrometric analysis of the glycosphingolipid-enriched microdomains of rat natural killer cells. Proteomics (2005) 5:113–22.[CrossRef][Web of Science][Medline]
  52. Hanna J, Fitchett J, Rowe T, et al. Proteomic analysis of human natural killer cells: insights on new potential NK immune functions. Mol Immunol (2005) 42:425–31.[CrossRef][Web of Science][Medline]
  53. Hanna J, Gonen-Gross T, Fitchett J, et al. Novel APC-like properties of human NK cells directly regulate T cell activation. J Clin Invest (2004) 114:1612–23.[CrossRef][Web of Science][Medline]
  54. Casey TM, Meade JL, Hewitt EW. Organelle proteomics: identification of the exocytic machinery associated with the natural killer cell secretory lysosome. Mol Cell Proteomics (2007) 6:767–80.[Abstract/Free Full Text]
  55. Hanna J, Bechtel P, Zhai Y, et al. Novel insights on human NK cells’ immunological modalities revealed by gene expression profiling. J Immunol (2004) 173:6547–63.[Abstract/Free Full Text]
  56. Phillips JH, Le AM, Lanier LL. Natural killer cells activated in a human mixed lymphocyte response culture identified by expression of Leu-11 and class II histocompatibility antigens. J Exp Med (1984) 159:993–1008.[Abstract/Free Full Text]
  57. Cooper MA, Fehniger TA, Caligiuri MA. The biology of human natural killer-cell subsets. Trends Immunol (2001) 22:633–40.[CrossRef][Web of Science][Medline]
  58. Cooper MA, Fehniger TA, Turner SC, et al. Human natural killer cells: a unique innate immunoregulatory role for the CD56(bright) subset. Blood (2001) 97:3146–51.[Abstract/Free Full Text]
  59. Anfossi N, Andre P, Guia S, et al. Human NK cell education by inhibitory receptors for MHC class I. Immunity (2006) 25:331–42.[CrossRef][Web of Science][Medline]
  60. Trotta R, Ciarlariello D, Dal Col J, et al. The PP2A inhibitor SET regulates natural killer cell IFN-{gamma} production. J Exp Med (2007) 204:2397–405.[Abstract/Free Full Text]
  61. Wendt K, Wilk E, Buyny S, et al. Gene and protein characteristics reflect functional diversity of CD56dim and CD56bright NK cells. J Leukoc Biol (2006) 80:1529–41.[Abstract/Free Full Text]
  62. Koopman LA, Kopcow HD, Rybalov B, et al. Human decidual natural killer cells are a unique NK cell subset with immunomodulatory potential. J Exp Med (2003) 198:1201–12.[Abstract/Free Full Text]
  63. Keskin DB, Allan DS, Rybalov B, et al. TGFbeta promotes conversion of CD16+ peripheral blood NK cells into CD16- NK cells with similarities to decidual NK cells. Proc Natl Acad Sci USA (2007) 104:3378–83.[Abstract/Free Full Text]
  64. Walzer T, Blery M, Chaix J, et al. Identification, activation, and selective in vivo ablation of mouse NK cells via NKp46. Proc Natl Acad Sci USA (2007) 104:3384–9.[Abstract/Free Full Text]
  65. Walzer T, Jaeger S, Chaix J, et al. Natural killer cells: from CD3(-)NKp46(+) to post-genomics meta-analyses. Curr Opin Immunol (2007) 19:365–72.[CrossRef][Web of Science][Medline]
  66. Russell JH, Ley TJ. Lymphocyte-mediated cytotoxicity. Annu Rev Immunol (2002) 20:323–70.[CrossRef][Web of Science][Medline]
  67. Lord SJ, Rajotte RV, Korbutt GS, et al. Granzyme B: a natural born killer. Immunol Rev (2003) 193:31–8.[CrossRef][Web of Science][Medline]
  68. Wowk ME, Trapani JA. Cytotoxic activity of the lymphocyte toxin granzyme B. Microbes Infect (2004) 6:752–8.[CrossRef][Web of Science][Medline]
  69. Harris JL, Peterson EP, Hudig D, et al. Definition and redesign of the extended substrate specificity of granzyme B. J Biol Chem (1998) 273:27364–73.[Abstract/Free Full Text]
  70. Backes C, Kuentzer J, Lenhof HP, et al. GraBCas: a bioinformatics tool for score-based prediction of caspase- and granzyme B-cleavage sites in protein sequences. Nucleic Acids Res (2005) 33:W208–13.[Abstract/Free Full Text]
  71. Caruso JA, Reiners JJ Jr. Proteolysis of HIP during apoptosis occurs within a region similar to the BID loop. Apoptosis (2006) 11:1877–85.[CrossRef][Web of Science][Medline]
  72. Goping IS, Sawchuk T, Underhill DA, et al. Identification of {alpha}-tubulin as a granzyme B substrate during CTL-mediated apoptosis. J Cell Sci (2006) 119:858–65.[Abstract/Free Full Text]
  73. Adrain C, Duriez PJ, Brumatti G, et al. The cytotoxic lymphocyte protease, granzyme B, targets the cytoskeleton and perturbs microtubule polymerization dynamics. J Biol Chem (2006) 281:8118–25.[Abstract/Free Full Text]
  74. Bredemeyer AJ, Lewis RM, Malone JP, et al. A proteomic approach for the discovery of protease substrates. Proc Natl Acad Sci USA (2004) 101:11785–90.[Abstract/Free Full Text]
  75. Bredemeyer AJ, Carrigan PE, Fehniger TA, et al. Hop cleavage and function in granzyme B-induced apoptosis. J Biol Chem (2006) 281:37130–41.[Abstract/Free Full Text]
  76. Hostetter DR, Loeb CR, Chu F, et al. Hip is a pro-survival substrate of granzyme B. J Biol Chem (2007) 282:27865–74.[Abstract/Free Full Text]
  77. Adrain C, Murphy BM, Martin SJ. Molecular ordering of the caspase activation cascade initiated by the cytotoxic T lymphocyte/natural killer (CTL/NK) protease granzyme B. J Biol Chem (2005) 280:4663–73.[Abstract/Free Full Text]
  78. Cullen SP, Adrain C, Luthi AU, et al. Human and murine granzyme B exhibit divergent substrate preferences. J Cell Biol (2007) 176:435–44.[Abstract/Free Full Text]
  79. Casciola-Rosen L, Garcia-Calvo M, Bull HG, et al. Mouse and human granzyme B have distinct tetrapeptide specificities and abilities to recruit the bid pathway. J Biol Chem (2007) 282:4545–52.[Abstract/Free Full Text]
  80. Kaiserman D, Bird CH, Sun J, et al. The major human and mouse granzymes are structurally and functionally divergent. J Cell Biol (2006) 175:619–30.[Abstract/Free Full Text]
  81. Loeb CR, Harris JL, Craik CS. Granzyme B proteolyzes receptors important to proliferation and survival, tipping the balance toward apoptosis. J Biol Chem (2006) 281:28326–35.[Abstract/Free Full Text]
  82. Cryns VL, Byun Y, Rana A, et al. Specific proteolysis of the kinase protein kinase C-related kinase 2 by caspase-3 during apoptosis. Identification by a novel, small pool expression cloning strategy. J Biol Chem (1997) 272:29449–53.[Abstract/Free Full Text]
  83. Li H, Zhu H, Xu CJ, et al. Cleavage of BID by caspase 8 mediates the mitochondrial damage in the Fas pathway of apoptosis. Cell (1998) 94:491–501.[CrossRef][Web of Science][Medline]
  84. Ju W, Valencia CA, Pang H, et al. Proteome-wide identification of family member-specific natural substrate repertoire of caspases. Proc Natl Acad Sci USA (2007) 104:14294–9.[Abstract/Free Full Text]
  85. Lieberman J, Fan Z. Nuclear war: the granzyme A-bomb. Curr Opin Immunol (2003) 15:553–9.[CrossRef][Web of Science][Medline]
  86. Chowdhury D, Beresford PJ, Zhu P, et al. The exonuclease TREX1 is in the SET complex and acts in concert with NM23-H1 to degrade DNA during granzyme A-mediated cell death. Mol Cell (2006) 23:133–42.[CrossRef][Web of Science][Medline]
  87. Zhu P, Zhang D, Chowdhury D, et al. Granzyme A, which causes single-stranded DNA damage, targets the double-strand break repair protein Ku70. EMBO Rep (2006) 7:431–7.[CrossRef][Web of Science][Medline]
  88. Andrade F, Fellows E, Jenne DE, et al. Granzyme H destroys the function of critical adenoviral proteins required for viral DNA replication and granzyme B inhibition. EMBO J (2007) 26:2148–57.[CrossRef][Web of Science][Medline]
  89. Zhao T, Zhang H, Guo Y, et al. Granzyme K directly processes bid to release cytochrome c and endonuclease G leading to mitochondria-dependent cell death. J Biol Chem (2007) 282:12104–11.[Abstract/Free Full Text]
  90. Zhao T, Zhang H, Guo Y, et al. Granzyme K cleaves the nucleosome assembly protein SET to induce single-stranded DNA nicks of target cells. Cell Death Differ (2007) 14:489–99.[CrossRef][Web of Science][Medline]
  91. Mahrus S, Kisiel W, Craik CS. Granzyme M is a regulatory protease that inactivates proteinase inhibitor 9, an endogenous inhibitor of granzyme B. J Biol Chem (2004) 279:54275–82.[Abstract/Free Full Text]

Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?


This article has been cited by other articles:


Home page
 Clin. Cancer Res.Home page
B. Boll, F. Eltaib, K. S. Reiners, B. von Tresckow, S. Tawadros, V. R. Simhadri, F. J. Burrows, K. Lundgren, H. P. Hansen, A. Engert, et al.
Heat Shock Protein 90 Inhibitor BIIB021 (CNF2024) Depletes NF-{kappa}B and Sensitizes Hodgkin's Lymphoma Cells for Natural Killer Cell-Mediated Cytotoxicity
Clin. Cancer Res., August 15, 2009; 15(16): 5108 - 5116.
[Abstract] [Full Text] [PDF]

Home page
 Anticancer ResHome page
A. Y. MAKINDE, X. LUO-OWEN, A. RIZVI, J. D. CRAPO, R. D. PEARLSTEIN, J. M. SLATER, and D. S. GRIDLEY
Effect of a Metalloporphyrin Antioxidant (MnTE-2-PyP) on the Response of a Mouse Prostate Cancer Model to Radiation
Anticancer Res, January 1, 2009; 29(1): 107 - 118.
[Abstract] [Full Text] [PDF]

This Article
Right arrow Abstract Freely available
Right arrow FREE Full Text (PDF) Freely available
Right arrow All Versions of this Article:
7/1/8    most recent
elm037v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Google Scholar
Right arrow Articles by Scott, G. B.
Right arrow Articles by Cook, G. P.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Scott, G. B.
Right arrow Articles by Cook, G. P.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?