Cell-Mediated Lympholysis of Fluorescein Isothiocyanate-Conjugated Autologous Human Cells: Evidence for Hapten-Specific Altered-Self Reactive Human Cytotoxic T Lymphocytes

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Abstract
The combined stimulus of FITCI-conjugated autologous cells plus either allogeneic cells, soluble antigens, or T cell-derived helper factor(s) triggers the in vitro differentiation of FITCI altered-self-reactive human CTL. Fractionation of responder cells into highly purified lymphocyte subpopulations and complement-mediated lysis of FITCI altered-self-reactive killer cells with rabbit anti-human T cell antibodies demonstrated that both the precursor and effector cell responsible for FITCI altered-self-cytolysis are T lymphocytes. Killer cell specificity was investigated in three experimental protocols: 1) the CTL generated were found to efficiently lyse FITCI but not TNP-modified autologous targets, whereas in reciprocal experiments, TNP altered-self-reactive CTL lyse TNP but not FITCI-derivitized autologous cells; 2) T cell-mediated lysis of 51Cr-labeled FITCI-derivitized autologous targets was specifically inhibited by nonradiolabeled FITCI but not TNP-modified autologous cells; and 3) FITCI altered self-reactive CTL specifically lyse some but not other FITCI-modified allogeneic targets. Taken together, these results show that although the FITCI altered-self-reactive human CTL generated are hapten specific, they appear to recognize more than hapten alone on the target cell surface. Moreover, the observation that soluble antigens, allogeneic cells, and T cell helper factor(s) can facilitate hapten-specific CTL responses to both TNP and FITCI-conjugated autologous cells suggests that these helper stimuli act by preferentially triggering the differentiation of CTL precursors that have specifically interacted with chemically modified autologous stimulators.