Protection from lysis by natural killer cells of group 1 and 2 specificity is mediated by residue 80 in human histocompatibility leukocyte antigen C alleles and also occurs with empty major histocompatibility complex molecules (original) (raw)
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Journal of Experimental Medicine, 1995
Natural killer (NK) cells have been shown to express a clonally distributed ability to recognize HLA class I alleles. The previously defined NK clones belonging to "group 1" recognize HLA-Cw*0401 (Cw4) and other HLA-C alleles sharing Asn at position 77 and Lys at position 80. Conversely, the "group 2" NK clones recognize HLA-Cw*0302 (Cw3) and other HLA-C alleles characterized by Ser at position 77 and Asn at position 80. We assessed directly the involvement of these two residues in the capacity of NK cell clones to discriminate between the two groups of HLA-C alleles. To this end, Cw3 and Cw4 alleles were subjected to site-directed mutagenesis. Substitution of the amino acids typical of the Cw3 allele (Ser-77 and Asn-80) with those present in Cw4 (Ash-77 and Lys-80) resulted in a Cw3 mutant that was no longer recognized by group 2 NK cell clones, but that was recognized by group I clones. Analysis of Cw3 or Cw4 molecules containing single amino acid substitutions indicates roles for Lys-80 in recognition mediated by group I clones and for Ser-77 in recognition mediated by group 2 clones. These results demonstrate that NK-mediated specific recognition of HLA-C allotypes is affected by single natural amino acid substitutions at positions 77 and 80 of the heavy chain.
The Binding Site of NK Receptors on HLA-C Molecules
Immunity, 1997
Biassoni et al., 1996). NK cell inhibitory receptors (NKIR, p58 or p70 molecules) have an uncharged trans-Mar Valé s-Gó mez, Daniel M. Davis, Laszlo Pazmany, and Jack L. Strominger membrane anchor and a long cytoplasmic tail containing two ITIM motifs. Binding of the NKIR to class I MHC Department of Molecular and Cellular Biology Harvard University proteins leads to the recruitment of protein tyrosine phosphatases such as PTP1C and PTP1D and the gen-Cambridge, Massachusetts 01238 eration of a negative signal, which blocks NK cell killing (Burshtyn et al., 1996; Campbell et al., 1996; Fry et al., 1996; Olcese et al., 1996). NK cell-activating receptors Summary (NKAR, p50 molecules) have a transmembrane domain containing a lysine residue and a truncated cytoplasmic The protection of cells expressing class I HLA moledomain lacking the two ITIM motifs (Wagtmann et al., cules from NK lysis is mediated by natural killer cell 1995; Biassoni et al., 1996). Engagement of NKAR by inhibitory receptors (NKIR). Using site-directed mutaclass I MHC protein results in activation of the cell by genesis, residues on HLA-C that determine the locus an as yet uncharacterized signaling pathway. Moreover, specificity (␣Val-76), allotype group specificity (a dithe distribution of these molecules is not limited to NK morphism ␣Asn-80/Lys-80), and affinity of NKIR bindcells; their representation on subsets of T cells results ing (a second pair of dimorphisms, ␣Ala-73, Asp-90 or in novel inhibitory or activating functions (Phillips et al., ␣Thr-73, Ala-90) have been identified. Thus the "foot-1995; Mandelboim et al., 1996a). print" of the NKIR on the ␣1 helix of the class I MHC A binding site of the NK receptor molecules on HLA molecule HLA-C and its associated  strands are simiwas first located by experiments that revealed that the lar in position to the site occupied by superantigens patterns of class I HLA-mediated inhibition of NK cells on and behind the ␣1 helix of the class II MHC molecule could be correlated with a dimorphism of amino acid HLA-DR1, but further toward its C-terminus. The interresidues 77 and 80 of the ␣1 helix of HLA-C molecules mediate affinity binding of NKIR to HLA-C, determined (Colonna et al., 1993a, 1993b). More specifically, the by ␣73 and ␣90, has an essential role in preventing residue at ␣80 divides HLA-C alleles into two groups cross-reactivity and ensuring the availability of NK encoding either ␣Asn-80 or ␣Lys-80, which are able to cells for immunosurveillance; low affinity and high afinhibit separate subsets of NK cell clones, NK1-and finity mutants are both physiologically impaired. NK2-specific cells that express p58 molecules NKIR1 and NKIR2 (Mandelboim et al., 1996b). The pattern of
Journal of Experimental Medicine, 1995
The natural killer (NK) cell-specific p58 molecules EB6 and GL183 have been shown to represent the putative surface receptors for two distinct groups of human histocompatibility leukocyte antigen (HLA) C alleles. Interaction between p58 receptors and class I molecules expressed on target cells results in inhibition of the NK-mediated cytolytic activity and thus in target cell protection. In the present study, we show that EB6 molecules may also act as receptors mediating NK cell triggering. Activatory EB6 molecules were found to be confined only to certain donors. Moreover, in these donors, only a fraction of EB6+ NK clones expressed the activatory form of EB6 molecules, while the remaining clones expressed the conventional inhibitory form. Biochemical analysis of the activatory EB6 molecules revealed a molecular mass of approximately 50 kD (p50), thus differing from the 58-kD inhibitory form. This difference was not due to differential glycosylation of the same protein, as revealed...
Journal of Experimental Medicine, 1996
Natural killer cells express clonally distributed receptors specific for major histocompatibility complex class I molecules. The human leukocyte antigen (HLA)-C-specific receptors have been molecularly identified and cloned. They exist not only as inhibitory (p58) but also as activatory (1050) receptors. Here we show that p50 and p58 are highly homologous in their extracellular regions formed by two Ig-like domains. In contrast, major differences exist in their transmembrane and cytoplasmic portions. Whereas p58 displays a 76-84-amino acid cytoplasmic tail containing an unusual antigen receptor activation motif, p50 is characterized by a shorter 39-amino acid tail. In addition, whereas p58 has a nonpolar transmembrane portion, p50 contains the charged amino acid Lys. These data strongly suggest that receptors with identical HLA-C allele specificity can mediate functions of opposite sign owing to their different transmembrane/cytoplasmic portions.
Journal of immunology (Baltimore, Md. : 1950), 1998
Cytotoxicity of human NK cells is under negative control of killer cell Ig-like receptors (KIR) specific for HLA class I. To determine the specificity of five KIR containing two Ig domains (KIR2D), direct binding of soluble recombinant KIR2D to a panel of HLA class I transfectants was assayed. One soluble KIR2D, derived from an inhibitory receptor with a long cytoplasmic tail (KIR2DL1), bound to HLA-C allotypes containing asparagine 77 and lysine 80 in the heavy chain, as expected, since these allotypes inhibit lysis by NK cells expressing KIR2DL1. Surprisingly, another KIR2D (KIR2DL2), which inhibits NK lysis of cells expressing HLA-C molecules with serine 77 and asparagine 80, bound to HLA-C allotypes carrying either amino acid motif. Expression of the KIR2DL receptors in NK cells using recombinant vaccinia viruses confirmed these patterns of recognition, and identified KIR2DL3 as another KIR reacting with both groups of HLA-C allotypes. Mutagenesis of amino acid 44 in KIR2DL1 and...
Journal of Experimental Medicine, 1995
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 dass I molecules, is in dose 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.
Proceedings of the National Academy of Sciences, 1996
Natural killer (NK) cells express clonally distributed receptors for different groups of HLA class I alleles. The Z27 monoclonal antibody described in this study recognizes a p70 receptor specific for HLA-B alleles belonging to the Bw4 supertypic specificity. Single amino acid substitutions in the peptide-binding groove of HLA-B2705 molecules influenced the recognition by some, but not all, p7O/Z27+ clones. This suggests the existence of a limited polymorphism within the p7O family of receptors. The pattern of reactivity of monoclonal antibody Z27 revealed that Bw4-specific receptors may be expressed alone or in combination with different (GL183 and/or EB6) p58 molecules. Analysis of NK clones coexpressing p58 and p7O receptors allowed us to demonstrate that the two molecules represent physically and functionally independent receptors. The expression of p7O molecules either alone or in combination with EB6 molecules provided the molecular basis for understanding the cytolytic patter...