Self-recognition and the biased mature repertoire in TCR beta transgenic mice: the exception that supports the rule.

Detailed sequence analysis of the companion alpha chains in several T-cell receptor (TCR) beta chain transgenic mice have shown that the mature alpha chain repertoires of CD4+ T cells are biased toward the parental TCR alpha chain sequences. These studies further indicate that it is self-peptide-self-MHC recognition during positive intrathymic selection that biases the structure of the mature TCR alpha chain repertoire. To further establish the causative relationship, it is important to examine whether such a bias can be abolished when positive selection is absent. The human collagen IV-I-A(s) complex-specific KB TCR cannot be positively selected on the self-peptide-self-MHC complexes present in the I-A(s) strain. Therefore, the KB TCR beta chain transgenic mice offer a unique opportunity for addressing this issue.