Both intrathymic and peripheral selection modulate the differential expression of Vβ5 among CD4 and CD8 T cells

Abstract

Murine T cells expressing Vβ5 are characterized by (a) intrathymic deletion in the presence of I-E and products of endogenous mouse mammary tumor viruses, and (b) a greater representation in CD8+ relative to CD4+ peripheral T cells, thought to be due to more efficient intrathymic positive selection on class I rather than class II major histocompatibility complex antigens. We have engineered mice that are transgenic for a rearranged gene encoding a Vβ5+ β chain of the T cell receptor for antigen. Deletion is not predicted in I-E- Vβ5+ transgenic mice, and until the age of 2 wk, the CD4/CD8 ratio of peripheral T cells is >3:1 and indistinguishable between transgenic and nontransgenic mice. Tra..