1,721,115 research outputs found
HLA class-I-specific NK receptors belong to two distinct molecular families and display inhibitory or activating function.
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CD3-negative lymphokine-activated cytotoxic cells express the CD3 epsilon gene.
No full textThe expression of genes encoding different polypeptide chains of the TCR-CD3 complex was analyzed in a panel of cloned MHC-unrestricted cytotoxic cells. The clones were derived from CD3+ and CD3- human PBL. After expansion in rIL-2, all clones were able to lyse the NK-sensitive target cell line K562. In contrast, lysis of fresh tumor cells was achieved almost exclusively by CD3- clones. To test whether a known TCR-CD3 complex may be involved in MHC-unrestricted cytotoxicity, total RNA from nine CD3+ and 11 CD3- clones was isolated and hybridized with DNA probes for the TCR alpha-, beta-, and gamma-chains and for the CD3 gamma-, delta-, and epsilon-chains. TCR gamma transcripts were present at high levels in CD3+CD4- CD8- clones but were undetectable in all CD3- clones. Lysis of fresh tumor cells is an activity which can be independent of the TCR alpha beta and TCR gamma complexes because the CD3- clones did not express these TCR genes. Interestingly, all CD3- clones expressed CD3 epsilon transcripts, but not CD3 gamma- or delta-transcripts. CD3- lymphokine-activated cytotoxic cells may therefore be derived from immature T cells which do not yet express a complete CD3 complex. The CD3 epsilon chain, if expressed in CD3- cells in association with other molecules, could be involved in the activation and lytic function of these MHC-unrestricted cytotoxic cells
Reciprocal expression of CD70 and of its receptor, CD27, in human long term-activated T and natural killer (NK) cells: inverse regulation by cytokines and role in induction of cytotoxicity.
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The human natural cytotoxicity receptors (NCR) that induce HLA class I-independent NK cell triggering
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Cyclosporin-A inhibits IL-2 production by all human T-cell clones having this function, independent of the T4/T8 phenotype or the coexpression of cytolytic activity.
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