Cutting edge: CD4+ T cells kill CD8+ T cells via Fas/Fas ligand-mediated apoptosis.
To explore the possibility that CD4+ T cells, described to mediate the elimination of themselves or B lymphocytes, could also mediate the elimination of CD8+ T cells, we analyzed apoptotic phenomena in cocultures of CD4+ and CD8+ autologous T cell lines. The data show that CD8+ T cells were lysed by activated CD4+ helper T cells by a Fas/FasL-mediated mechanism. CD4+ T cells were not lysed by activated CD8+ T cells, although Fas and FasL were equally expressed and anti-Fas Abs induced apoptosis in both CD4+ and CD8+ T cell populations. The results allowed us to speculate that CD4+ T cells not only help CD8+ T lymphocytes to mature into effector killer cells and to sustain this function but can also limit their growth.
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Department of Cellular and Developmental Biology, University La Sapienza, National Research Council of Italy (CNR), Rome.
Gilardini Montani
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Moretti
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Cundari
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Piccolella
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D017209:Apoptosis / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002454:Cell Differentiation / Q000276:immunology; D002455:Cell Division / Q000276:immunology; D003602:Cytotoxicity, Immunologic; D053222:Fas Ligand Protein; D006801:Humans; D007694:Killer Cells, Natural / Q000166:cytology / Q000276:immunology; D008024:Ligands; D008213:Lymphocyte Activation; D008562:Membrane Glycoproteins / Q000494:pharmacology*; D019014:fas Receptor / Q000494:pharmacology*
C505661:FASLG protein, human; D053222:Fas Ligand Protein; D008024:Ligands; D008562:Membrane Glycoproteins; D019014:fas Receptor