EXPRESSION OF 2 ALPHA-CHAINS ON THE SURFACE OF T-CELLS IN T-CELL RECEPTOR TRANSGENIC MICE

CD8+ T cells taken directly from mice expressing a K(b)-specific T cel l receptor (TCR) transgene expressed the transgenic TCR in a bimodal p rofile as detected by flow cytometric analysis using a clonotype-speci fic monoclonal antibody. Those cells expressing the lower density of t he transgenic TCR expressed the transgenic beta chain and two differen t alpha chains on their surface. One alpha chain was the product of th e alpha transgene, whereas the other was derived by endogenous rearran gement. This report provides the first demonstration that T cells isol ated directly from mice may express two different TCR clonotypes on th eir surface. The potential consequences of this finding for studies us ing TCR transgenic mice and for the induction of autoimmunity are disc ussed.