| Abstract: |
Antigen-specific cytotoxlc killer lymphocytes (CTLs) represent one of the major effector functions of the immune system. It is well established that, as a consequence of TCR recognition of the antigen-bearing target cell, resting T lymphocytes develop Into fully active antigen-specific CTLs. In contrast, natural killer (NK) cells are immediately tytic upon contact with an appropriate target cell. The tytic machinery of CTLs and NK cells Is thought to include the contents of their cytoplasmlc granules, in particular the pore-forming protein perforin. Here we report direct cytolytic activity by resting peripheral CD3+CD8+ T cells as a result of TCR-CD3 binding to the target cell; the murine OKT3 hybridoma (anti-human CD3) was used as a target. The cytotoxicity was more pronounced In the CD8+CD45RO+ population, which contains 'memory' T cells, than In the reciprocal CD8+CD45RA+ subset; CD8+CD4- mature thymocytes were non-cytotoxlc. The cytolytic potential of these populations correlated with the presence or absence of perforin. The results demonstrate that the cytolytic machinery of T cells develops post-thymically and can be Immediately triggered by TCR-CD3 stimulation. © 1992 Oxford University Press. |
| Keywords: |
adult; human cell; comparative study; cd3 antigen; antigens, cd3; cells, cultured; cytotoxicity; tumor cells, cultured; t lymphocyte receptor; lymphocyte activation; antibodies, monoclonal; antigens; receptors, antigen, t-cell; membrane glycoproteins; cytotoxic t lymphocyte; t-lymphocytes, cytotoxic; natural killer cell; killer cells, natural; perforin; cytotoxicity, immunologic; immunophenotyping; t-lymphocyte subsets; antigens, cd; cell separation; thymocyte; centrifugation, density gradient; normal human; antigens, differentiation, t-lymphocyte; t cell receptor; tumor stem cells; cytoplasmic granules; human; priority journal; article; support, u.s. gov't, p.h.s.; t ceil activation; t cell maturation
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