CD3/TI-GAMMA-A - A FUNCTIONAL GAMMA-RECEPTOR COMPLEX EXPRESSED ON HUMAN PERIPHERAL LYMPHOCYTES

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  • 1 March 1988
    • journal article
    • research article
    • Vol. 140  (5) , 1372-1379
Abstract
We have recently developed a mAb designated anti-Ti.gamma.A, which was found to immunoprecipitate from the well characterized CD3+ TCR .alpha./.beta.-F6C7 fetal clone a CD3-associated disulfide-linked .gamma.-glycoprotein. This antibody recognizes approximately 3% of adult peripheral lymphocytes and delineates a CD2+CD3+TCR .alpha./.beta.- CD4- NKH1- subset where expression of CD8 appears to vary widely from one individual to another. In the present study, we have used anti-Ti.GAMMA.A mAb to assess whether .gamma.-chains expressed on these adult lymphocytes are used as functional R. The two activities which have been associated thus far with TCR .gamma.+ cells, that is, IL-2-dependent proliferation and non-MHC-restricted cytotoxicity, were investigated here by using either resting or activated Ti.gamma.A+ lymphocytes. On the resting state, these cells (which appear as a very homogeneous population of granular lymphocytes) mediate little if any NK activity that could not be augmented by anti-Ti.gamma.A mAb. In contrast, after initial stimulation by PHA plus rIL-2 and subsequent culture in the presence of IL-2, activated Ti.gamma.A+ lymphocytes were strongly lytic against a series of conventional NK target cell lines. This cytotoxic function was either blocked or enhanced by anti-Ti.gamma.A mAb, depending upon experimental conditions. With respect to proliferation, it was possible to induce responses of resting Ti.gamma.+ lymphocytes with antibody-coated CNBr beads only in the presence of exogenous IL-2, whereas in culture, the same cells proliferated directly and secreted IL-2, after treatment by anti-Ti.gamma.A beads. Taken together, these data demonstrate that a major subset of circulating CD3+ TCR .alpha./.beta.- lymphocytes use protein products of T cell .gamma. rearranging genes as functional R structures.