scholarly journals Inhibitory Receptors Alter Natural Killer Cell Interactions with Target Cells Yet Allow Simultaneous Killing of Susceptible Targets

1999 ◽  
Vol 190 (7) ◽  
pp. 1005-1012 ◽  
Author(s):  
Mikael Eriksson ◽  
Guenther Leitz ◽  
Erik Fällman ◽  
Ove Axner ◽  
James C. Ryan ◽  
...  

Inhibitory receptors expressed on natural killer (NK) cells abrogate positive signals upon binding corresponding major histocompatibility complex (MHC) class I molecules on various target cells. By directly micromanipulating the effector–target cell encounter using an optical tweezers system which allowed temporal and spatial control, we demonstrate that Ly49–MHC class I interactions prevent characteristic cellular responses in NK cells upon binding to target cells. Furthermore, using this system, we directly demonstrate that an NK cell already bound to a resistant target cell may simultaneously bind and kill a susceptible target cell. Thus, although Ly49-mediated inhibitory signals can prevent many types of effector responses, they do not globally inhibit cellular function, but rather the inhibitory signal is spatially restricted towards resistant targets.

Blood ◽  
2010 ◽  
Vol 115 (6) ◽  
pp. 1166-1174 ◽  
Author(s):  
Cyril Fauriat ◽  
Martin A. Ivarsson ◽  
Hans-Gustaf Ljunggren ◽  
Karl-Johan Malmberg ◽  
Jakob Michaëlsson

Abstract Expression of inhibitory killer cell immunoglobulin-like receptors (KIRs) specific for self–major histocompatibility complex (MHC) class I molecules provides an educational signal that generates functional natural killer (NK) cells. However, the effects of activating KIRs specific for self-MHC class I on NK-cell education remain elusive. Here, we provide evidence that the activating receptor KIR2DS1 tunes down the responsiveness of freshly isolated human NK cells to target cell stimulation in donors homozygous for human leukocyte antigen (HLA)–C2, the ligand of KIR2DS1. The tuning was apparent in KIR2DS1+ NK cells lacking expression of inhibitory KIRs and CD94/NKG2A, as well as in KIR2DS1+ NK cells coexpressing the inhibitory MHC class I–specific receptors CD94/NKG2A and KIR2DL3, but not KIR2DL1. However, the tuning of responsiveness was restricted to target cell recognition because KIR2DS1+ NK cells responded well to stimulation with exogenous cytokines. Our results provide the first example of human NK-cell education by an activating KIR and suggest that the education of NK cells via activating KIRs is a mechanism to secure tolerance that complements education via inhibitory KIRs.


1993 ◽  
Vol 178 (3) ◽  
pp. 961-969 ◽  
Author(s):  
M S Malnati ◽  
P Lusso ◽  
E Ciccone ◽  
A Moretta ◽  
L Moretta ◽  
...  

Natural killer (NK) cells provide a first line of defense against viral infections. The mechanisms by which NK cells recognize and eliminate infected cells are still largely unknown. To test whether target cell elements contribute to NK cell recognition of virus-infected cells, human NK cells were cloned from two unrelated donors and assayed for their ability to kill normal autologous or allogeneic cells before and after infection by human herpesvirus 6 (HHV-6), a T-lymphotropic herpesvirus. Of 132 NK clones isolated from donor 1, all displayed strong cytolytic activity against the NK-sensitive cell line K562, none killed uninfected autologous T cells, and 65 (49%) killed autologous T cells infected with HHV-6. A panel of representative NK clones from donors 1 and 2 was tested on targets obtained from four donors. A wide heterogeneity was observed in the specificity of lysis of infected target cells among the NK clones. Some clones killed none, some killed only one, and others killed more than one of the different HHV-6-infected target cells. Killing of infected targets was not due to complete absence of class I molecules because class I surface levels were only partially affected by HHV-6 infection. Thus, target cell recognition is not controlled by the effector NK cell alone, but also by polymorphic elements on the target cell that restrict NK cell recognition. Furthermore, NK clones from different donors display a variable range of specificities in their recognition of infected target cells.


1995 ◽  
Vol 181 (3) ◽  
pp. 1133-1144 ◽  
Author(s):  
J E Gumperz ◽  
V Litwin ◽  
J H Phillips ◽  
L L Lanier ◽  
P Parham

Although inhibition of natural killer (NK) cell-mediated lysis by the class I HLA molecules of target cells is an established phenomenon, knowledge of the features of class I molecules which induce this effect remains rudimentary. Using class I alleles HLA-B*1502 and B*1513 which differ only at residues 77-83 which define the Bw4 and Bw6 serological epitopes, we tested the hypothesis that the presence of the Bw4 epitope on class I molecules determines recognition by NKB1+ NK cells. HLA-B*1513 possesses the Bw4 epitope, whereas B*1502 has the Bw6 epitope. Lysis by NKB1+ NK cell clones of transfected target cells expressing B*1513 as the only HLA-A, -B, or -C molecule was inhibited, whereas killing of transfectants expressing B*1502 was not. Addition of an an anti-NKB1 monoclonal antibody reconstituted lysis of the targets expressing B*1513, but did not affect killing of targets bearing B*1502. The inhibitory effect of B*1513 could be similarly prevented by the addition of an anti-class I monoclonal antibody. These results show that the presence of the Bw4 epitope influences recognition of HLA-B molecules by NK cells that express NKB1, and suggest that the NKB1 molecule may act as a receptor for Bw4+ HLA-B alleles. Sequences outside of the Bw4 region must also affect recognition by NKB1+ NK cells, because lysis of transfectants expressing HLA-A*2403 or A*2501, which possess the Bw4 epitope but are in other ways substantially different from HLA-B molecules, was not increased by addition of the anti-NKB1 antibody. Asparagine 86, the single site of N-linked glycosylation on class I molecules, is in close proximity to the Bw4/Bw6 region. The glycosylation site of the Bw4-positive molecule B*5801 was mutated, and the mutant molecules tested for inhibition of NKB1+ NK cells. Inhibition that could be reversed by addition of the anti-NKB1 monoclonal antibody was observed, showing the presence of the carbohydrate moiety is not essential for class I recognition by NKB1+ NK cell clones.


1993 ◽  
Vol 178 (4) ◽  
pp. 1321-1336 ◽  
Author(s):  
V Litwin ◽  
J Gumperz ◽  
P Parham ◽  
J H Phillips ◽  
L L Lanier

Prior studies using polyclonal populations of natural killer (NK) cells have revealed that expression of certain major histocompatibility complex (MHC) class I molecules on the membrane of normal and transformed hematopoietic target cells can prevent NK cell-mediated cytotoxicity. However, the extent of clonal heterogeneity within the NK cell population and the effect of self versus non-self MHC alleles has not been clearly established. In the present study, we have generated more than 200 independently derived human NK cell clones from four individuals of known human histocompatibility leukocyte antigens (HLA) type. NK clones were analyzed for cytolytic activity against MHC class I-deficient Epstein Barr virus (EBV) transformed B lymphoblastoid cell lines (B-LCL) stably transfected with several HLA-A, -B, or -C genes representing either self or non-self alleles. All NK clones killed the prototypic HLA-negative erythroleukemia K562 and most lysed the MHC class I-deficient C1R and 721.221 B-LCL. Analysis of the panel of HLA-A, -B, and -C transfectants supported the following general conclusions. (a) Whereas recent studies have suggested that HLA-C antigens may be preferentially recognized by NK cells, our findings indicate that 70% or more of all NK clones are able to recognize certain HLA-B alleles and many also recognize HLA-A alleles. Moreover, a single NK clone has the potential to recognize multiple alleles of HLA-A, HLA-B, and HLA-C antigens. Thus, HLA-C is not unique in conferring protection against NK lysis. (b) No simple patterns of HLA specificity emerged. Examination of a large number of NK clones from a single donor revealed overlapping, yet distinct, patterns of reactivity when a sufficiently broad panel of HLA transfectants was examined. (c) Both autologous and allogeneic HLA antigens were recognized by NK clones. There was neither evidence for deletion of NK clones reactive with self alleles nor any indication for an increased frequency of NK clones recognizing self alleles. (d) With only a few exceptions, protection conferred by transfection of HLA alleles into B-LCL was usually not absolute. Rather a continuum from essentially no protection for certain alleles (HLA-A*0201) to very striking protection for other alleles (HLA-B*5801), with a wide range of intermediate effects, was observed. (e) Whereas most NK clones retained a relatively stable HLA specificity, some NK clones demonstrated variable and heterogeneous activity over time. (f) NK cell recognition and specificity cannot be explained entirely by the presence or absence of HLA class I antigens on the target cell.(ABSTRACT TRUNCATED AT 400 WORDS)


2003 ◽  
Vol 10 (2-4) ◽  
pp. 183-192 ◽  
Author(s):  
Mali Salmon-Divon ◽  
Petter Höglund ◽  
Ramit Mehr

Natural killer (NK) cells lyse only cells that do not express sufficient levels of self class I MHC molecules. Inhibition of lysis is mediated by inhibitory receptors expressed by NK cells, such as the murine Ly49 receptors, that bind to MHC class I molecules. Since inhibitory receptor genes and MHC class I genes are located on different chromosomes, and are hence not automatically co-inherited, NK cells apparently adapt to the MHC environment during their development. Two models have been proposed to account for this “education” process of NK cells. Thetwo-step selectionmodel postulates that developing NK cells initiate the stable expression of a random set of Ly49 genes, and then undergo two selection steps, one for cells that express a sufficient number of self-MHC receptors, and one against cells that express too many inhibitory receptors. Thesequentialmodel postulates that a cell keeps initiating the stable expression of additional inhibitory receptors until a sufficient expression level of self-MHC specific receptors is reached, and the cell matures. In this study we implement both models in computer simulations, and compare simulation results to experimental data, in order to evaluate the relative plausibility of the two models.


2000 ◽  
Vol 191 (1) ◽  
pp. 129-138 ◽  
Author(s):  
Rickard Glas ◽  
Lars Franksson ◽  
Clas Une ◽  
Maija-Leena Eloranta ◽  
Claes Öhlén ◽  
...  

Natural killer (NK) cells can spontaneously lyse certain virally infected and transformed cells. However, early in immune responses NK cells are further activated and recruited to tissue sites where they perform effector functions. This process is dependent on cytokines, but it is unclear if it is regulated by NK cell recognition of susceptible target cells. We show here that infiltration of activated NK cells into the peritoneal cavity in response to tumor cells is controlled by the tumor major histocompatibility complex (MHC) class I phenotype. Tumor cells lacking appropriate MHC class I expression induced NK cell infiltration, cytotoxic activation, and induction of transcription of interferon γ in NK cells. The induction of these responses was inhibited by restoration of tumor cell MHC class I expression. The NK cells responding to MHC class I–deficient tumor cells were ∼10 times as active as endogenous NK cells on a per cell basis. Although these effector cells showed a typical NK specificity in that they preferentially killed MHC class I–deficient cells, this specificity was even more distinct during induction of the intraperitoneal response. Observations are discussed in relation to a possible adaptive component of the NK response, i.e., recruitment/activation in response to challenges that only NK cells are able to neutralize.


Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. SCI-25-SCI-25
Author(s):  
Peter Parham

Abstract Natural killer (NK) cells are phenotypically diverse lymphocytes that contribute to innate immunity, adaptive immunity and placental reproduction. Unlike B and T cells, NK cells do not use rearranging genes to make diverse antigen receptors that are clonally expressed. Instead, NK cells express diverse combinations of a variety of receptors that are encoded by conventional non-rearranging genes. Several of these receptors are specific for conserved and variable determinants of major histocompatibility complex (MHC) class I molecules. In humans, the killer-cell immunoglobulin-like receptors (KIR) are a diverse and polymorphic family of NK-cell receptors that recognize determinants of human leukocyte antigen (HLA)-A, B and C, the polymorphic human MHC class I molecules. HLA-A, B and C are the most polymorphic of human genes, and they correlate with susceptibility to a wide range of diseases and clinical outcomes, including allogeneic hematopoietic cell transplantation (HCT). During NK-cell development, interactions between epitopes of HLA class I and KIR educate the NK cells to recognize the normal expression of these epitopes on healthy cells, and to respond to unhealthy cells in which that expression is perturbed. In the context of HCT, certain types of HLA class I mismatch enable donor-derived NK cells to make an alloreactive and beneficial graft-versus-leukemia response. Although it is likely that all placental mammals have NK cells, only a small minority of these species has a diverse KIR family like that in humans. These comprise the simian primates: New World monkeys, Old World monkeys and the great apes. Under pressure from diverse and rapidly evolving pathogens, both the MHC class I and KIR gene families have been driven to evolve rapidly. Consequently, much of their character is species-specific. This is especially true for the human KIR gene family, which is qualitatively different from that of our closest relatives, the chimpanzees. Whereas chimpanzee KIR haplotype diversity represents variations on a theme of genes encoding robust MHC class I receptors, humans have an even balance between group A KIR haplotypes encoding robust HLA class I receptors and group B KIR haplotypes encoding receptors that, to varying degree, have been subject to natural selection for reduced functional recognition of HLA class I. A balance of A and B is present in all human populations and thus appears essential for the long-term survival and competitiveness of human communities. Whereas the A KIR haplotypes correlate with successful defense against viral infection, maternal B KIR haplotypes correlate with reproductive success and donor B KIR haplotypes improve the outcome of allogeneic HCT as therapy for acute myeloid leukemia. Disclosures No relevant conflicts of interest to declare.


1996 ◽  
Vol 184 (2) ◽  
pp. 505-518 ◽  
Author(s):  
D Pende ◽  
R Biassoni ◽  
C Cantoni ◽  
S Verdiani ◽  
M Falco ◽  
...  

Human natural killer (NK) cells express inhibitory receptors that are specific for different groups of HLA-C or HLA-B alleles. The majority of these receptors belong to the immunoglobulin (Ig) superfamily and are characterized by two or three extracellular Ig-like domains. Here we describe a novel inhibitory NK receptor that is specific for a group of HLA-A alleles. The HLA-A3-specific NK cell clone DP7 has been used for mice immunization. Two mAbs, termed Q66 and Q241, bound to the immunizing clone and stained only a subset of NK cell populations or clones. Among Q66 mAb-reactive clones, we further selected those that did not express any of the previously identified HLA-class I-specific NK receptors. These clones did not lyse HLA-A3+ (or -A11+) target cells, but lysis of these targets could be detected in the presence of Q66 or Q241 mAbs. On the other hand, target cells expressing other HLA-A alleles, including -A1, -A2, and -A24, were efficiently lysed. Moreover, none of the HLA-C or HLA-B alleles that were tested exerted a protective effect. Q66+, but not Q66- NK cell clones, expressed messenger RNA coding for a novel 3 Ig domain protein homologous to the HLA-C (p58) and HLA-B (p70) receptors. The corresponding cDNA (cl.1.1) was used to generate transient and stable transfectants in COS7 and NIH3T3 cell lines, respectively. Both types of transfectants were specifically stained by Q66 and Q241 mAbs. Since the cytoplasmic tail of Q66-reactive molecules was at least 11 amino acid longer than the other known p58/p70 molecules, we could generate an antiserum specific for the COOH-terminus of Q66-reactive molecules, termed PGP-3. PGP-3 immunoprecipitated, only from Q66+ NK cells, molecules displaying a molecular mass of 140 kD, under nonreducing conditions, which resolved, under reducing conditions, in a 70-kD band. Thus, differently from the other p58/p70 receptors, Q66-reactive molecules appear to be expressed as disulphide-linked dimers and were thus termed p140. The comparative analysis of the amino acid sequences of p58, p70, and p140 molecules revealed the existence of two cysteins proximal to the transmembrane region, only in the amino acid sequence of p140 molecules.


1998 ◽  
Vol 188 (10) ◽  
pp. 1841-1848 ◽  
Author(s):  
Russell E. Vance ◽  
Jennifer R. Kraft ◽  
John D. Altman ◽  
Peter E. Jensen ◽  
David H. Raulet

Natural killer (NK) cells preferentially lyse targets that express reduced levels of major histocompatibility complex (MHC) class I proteins. To date, the only known mouse NK receptors for MHC class I belong to the Ly49 family of C-type lectin homodimers. Here, we report the cloning of mouse NKG2A, and demonstrate it forms an additional and distinct class I receptor, a CD94/NKG2A heterodimer. Using soluble tetramers of the nonclassical class I molecule Qa-1b, we provide direct evidence that CD94/NKG2A recognizes Qa-1b. We further demonstrate that NK recognition of Qa-1b results in the inhibition of target cell lysis. Inhibition appears to depend on the presence of Qdm, a Qa-1b-binding peptide derived from the signal sequences of some classical class I molecules. Mouse NKG2A maps adjacent to CD94 in the heart of the NK complex on mouse chromosome six, one of a small cluster of NKG2-like genes. Our findings suggest that mouse NK cells, like their human counterparts, use multiple mechanisms to survey class I expression on target cells.


2001 ◽  
Vol 194 (10) ◽  
pp. 1519-1530 ◽  
Author(s):  
Anna Sjöström ◽  
Mikael Eriksson ◽  
Cristina Cerboni ◽  
Maria H. Johansson ◽  
Charles L. Sentman ◽  
...  

Murine natural killer (NK) cells express inhibitory Ly49 receptors specific for major histocompatibility complex (MHC) class I molecules. We report that during interactions with cells in the environment, NK cells acquired MHC class I ligands from surrounding cells in a Ly49-specific fashion and displayed them at the cell surface. Ligand acquisition sometimes reached 20% of the MHC class I expression on surrounding cells, involved transfer of the entire MHC class I protein to the NK cell, and was independent of whether or not the NK cell expressed the MHC class I ligand itself. We also present indirect evidence for spontaneous MHC class I acquisition in vivo, as well as describe an in vitro coculture system with transfected cells in which the same phenomenon occurred. Functional studies in the latter model showed that uptake of H-2Dd by Ly49A+ NK cells was accompanied by a partial inactivation of cytotoxic activity in the NK cell, as tested against H-2Dd-negative target cells. In addition, ligand acquisition did not abrogate the ability of Ly49A+ NK cells to receive inhibitory signals from external H-2Dd molecules. This study is the first to describe ligand acquisition by NK cells, which parallels recently described phenomena in T and B cells.


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