title: Selective stimulation of thymocyte precursors mediated by specific cytokines. Different CD3+ subsets are generated by IL-1 versus IL-2.
abstract: The sequence of activation signals that stimulate proliferation, differentiation, and selection of mature T cell subsets from immature, dull-CD5+/CD4-, CD8- double negative (bCD5), (dCD5/DN) thymocytes are still unclear. However, it is likely that cytokines play integral roles in these events. Here we report that IL-1, in the presence of Con A, supports the proliferation and differentiation of highly purified dCD5/DN precursors into bright-CD5+ DN, CD2- lymphocytes with an apparently mature phenotype. These cells express CD3 and preferentially express the products of two TCR gene families, V beta 8 and V beta 6, whose expression is dependent on the allelic expression of the Mls-1 locus. Experiments, using DN thymocytes mixed with purified dCD5 subset of DN cells from a congenic strain of mice (i.e., expressing two different alleles of CD5) have shown that the cells that are stimulated by IL-1 and comitogen are derived from the immature dCD5 subset and not from the mature bCD5 cells contained within the DN subset. In contrast, IL-2 with the co-mitogen stimulates three- to fourfold higher levels of proliferation, from the same purified immature precursor population, and nearly a twofold increase in cell yield. However, the cells that were generated from precursor thymic cells stimulated with IL-2 represent a completely different T cell subset compared to IL-1-generated cells; these IL-2-stimulated cells express comparable levels of CD3, but also express substantial levels of CD2 and the TCR-gamma/delta, and a subset expresses CD8. These data suggest that these two TCR-alpha/beta and TCR-gamma/delta subsets of mature thymocytes use different cytokines and therefore possibly different stromal interactions to initiate differentiation.
authors.affiliation: Biological Carcinogenesis Development Program, Program Resources Inc., Frederick, MD.
authors.forename: W H
authors.initials: WH
authors.lastname: Gotlieb
authors.forename: S K
authors.initials: SK
authors.lastname: Durum
authors.forename: T A
authors.initials: TA
authors.lastname: Gregorio
authors.forename: B J
authors.initials: BJ
authors.lastname: Mathieson
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D000943:Antigens, Differentiation / Q000032:analysis; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis; D018801:CD2 Antigens; D015704:CD4 Antigens / Q000032:analysis; D018956:CD5 Antigens; D016827:CD8 Antigens; D002454:Cell Differentiation / Q000187:drug effects; D005434:Flow Cytometry; D015870:Gene Expression; D066298:In Vitro Techniques; D007375:Interleukin-1 / Q000494:pharmacology*; D007376:Interleukin-2 / Q000494:pharmacology*; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D011948:Receptors, Antigen, T-Cell / Q000145:classification / Q000235:genetics; D011971:Receptors, Immunologic / Q000032:analysis; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D013950:Thymus Gland / Q000166:cytology
chemical_list: D000911:Antibodies, Monoclonal; D000943:Antigens, Differentiation; D000945:Antigens, Differentiation, T-Lymphocyte; D018801:CD2 Antigens; D015704:CD4 Antigens; D018956:CD5 Antigens; D016827:CD8 Antigens; D007375:Interleukin-1; D007376:Interleukin-2; D011948:Receptors, Antigen, T-Cell; D011971:Receptors, Immunologic