Acquisition of non-MHC restricted cytotoxic function by IL 2 activated thymocytes with an "immature" antigenic phenotype.
Culture of human thymocytes in interleukin 2 (IL 2) results in the generation of cytotoxic T lymphocytes (CTL) that kill tumor cell targets without major histocompatibility complex (MHC) restriction. Thymic non-MHC restricted CTL expressed Leu-19 antigen, but were generated from thymic precursor cells that lacked expression of Leu-19. In contrast, short term culture in Il 2 of peripheral blood lymphocytes depleted of Leu-19+ lymphocytes did not result in the generation of cytotoxic activity. IL 2 was necessary and sufficient for the generation of cytotoxic thymocytes and induction of Leu-19 antigen expression. Thymic non-MHC restricted CTL were generated from precursor cells expressing CD1, an antigen present on the majority of thymocytes. Furthermore, cytotoxic activity was detected in IL 2 cultured thymocyte populations with an "immature" antigenic phenotype, i.e. CD1+ and CD4+, CD8+. Upon subsequent culture, thymic non-MHC restricted CTL lost expression of CD1, and developed an antigenic phenotype similar to peripheral blood non-MHC-restricted CTL, suggesting that peripheral non-MHC-restricted CTL may originate from these thymic precursors.
D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface / Q000276:immunology*; D002454:Cell Differentiation; D002469:Cell Separation; D005434:Flow Cytometry; D006801:Humans; D007376:Interleukin-2 / Q000494:pharmacology*; D010641:Phenotype; D011994:Recombinant Proteins / Q000494:pharmacology; D013602:T-Lymphocytes, Cytotoxic / Q000187:drug effects / Q000276:immunology*; D013950:Thymus Gland / Q000166:cytology
D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D007376:Interleukin-2; D011994:Recombinant Proteins