Description: The B21.5 monoclonal antibody reacts with the Vβ10 T-Cell Receptor (TCR) in mice of the β haplotype of the Tcrb gene complex, which includes AKR, BALB/c, CBA, C3H/He, C57BL, DBA/1 and DBA/2 mice. It does not react with mice having the a or bTcrb haplotype, including C57BR, C57L or SJL mice.