EXPRESSION OF 2 T-CELL RECEPTOR-ALPHA CHAINS ON THE SURFACE OF NORMALMURINE T-CELLS

We have previously reported that a subset of T cells in T cell recepto r (TCR)-transgenic mice may express two different a chains on their su rface. The expression of two functional a chains has also been demonst rated for human peripheral blood T cells. In this report, we show that a proportion of normal murine lymph node T cells express two function al a chains on their surface. The extrapolated frequency of these cell s present in the normal repertoire ranges from 7-21 %, with an average of 15 %. Our analysis of a small number of antigen-specific T cell cl ones suggests that the frequency of antigen-responsive cells expressin g two surface a chains is relatively low. This raises the possibility that dual a chain T cells may have a selective disadvantage in respond ing to specific antigen.