Murine thymic CD4+ T cell subsets: a subset (Thy0) that secretes diverse cytokines and overexpresses the V beta 8 T cell receptor gene family.
We demonstrate here the presence of a distinct mature CD4+8- T cell subset in mouse thymus. This subset, termed "Thy0," is delineated by the absence of 3G11 expression from about half of the 6C10-/HSAlow/- fraction of CD4+8- thymic cells. Thy0 is detectable from the neonatal period and largely contributes the Th0-type diverse cytokine production previously reported for the HSAlow/-CD4+ thymic population. Further, cells expressing the T cell receptor V beta 8 gene family are found at increasing frequency in Thy0 with age, comprising 40-60% of Thy0 in adult BALB/c mice. This alteration of V beta 8+ cell frequency is unique to Thy0, since no other CD4+ subset in thymus or spleen shows such V beta 8 overusage. All functional CD4+ T cell subsets, including Thy0, show appropriate V beta clonal deletion associated with endogenous superantigens. Thus, it appears that Thy0 is an intrathymically generated secondary cell subset produced after CD4+ T cell selection.
Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111.
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D000367:Age Factors; D000818:Animals; D000954:Antigens, Surface / Q000032:analysis; D015704:CD4 Antigens / Q000032:analysis; D015496:CD4-Positive T-Lymphocytes / Q000502:physiology*; D016827:CD8 Antigens / Q000032:analysis; D016207:Cytokines / Q000096:biosynthesis*; D005260:Female; D015870:Gene Expression; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics*
D000954:Antigens, Surface; D015704:CD4 Antigens; D016827:CD8 Antigens; D016207:Cytokines; D016693:Receptors, Antigen, T-Cell, alpha-beta