T cell receptor expression by T cells that mature extrathymically in nude mice

The expression of TCR by T cells that mature extrathymically in nude mice was determined by staining Ig- cells from B10 nude mice that were 5 months of age or older with mAbs specific for CD3, alpha/beta or gamma/delta TCR. Although the majority of Ig- cells in older nude mice express TCR, the distribution of alpha/beta and gamma/delta TCR in relation to CD4 and CD8 expression is markedly different compared to T cells from euthymic mice. Approximately half of the CD3+ T cells found in the spleen and lymph nodes of nude mice express gamma/delta TCR that is equally distributed between CD4-8- double-negative and CD8+ single-positive T cells. These data provide the first quantitative measure of the expression of TCR by T cells that mature in the absence of a thymus and suggest that the extrathymic environment, although not efficient, is permissive for the maturation of T cells that express alpha/beta and gamma/delta TCR.