Molecular basis for the nonexpression of V beta 17 in some strains of mice.

The TCR alpha/beta variable element V beta 17a is expressed in all strains of mice carrying the V beta a complex in which about half of the V beta elements have been lost due to a large deletion. The mAb KJ23a detects V beta 17a containing alpha/beta receptors in these mice. Mouse strains with the V beta b complex carry a full complement of V beta genes including a structural gene for V beta 17 (V beta 17b), but no T cells reactive with KJ23a are present in these mice. Among random peripheral T cell hybridomas prepared from V beta b mice, occasional V beta 17b transcripts are found. The sequence of one of these transcripts reveals a single base difference from V beta 17a which results in a termination codon within the coding region inactivating the gene.