Is beta t a component of HLA-A,B,C in thymus derived cells?

beta t, the 12,000 molecular weight polypeptide originally found in HTA 1, a thymus specific differentiation antigen, is a major labelled component of surface iodinated HLA-A,B,C purified by monoclonal antibody W6/32 from the T leukaemia cell line Molt 4. A correlation between the amount of beta t in HLA-A,B,C and the level of HTA 1 expression in Molt 4 and variants derived from it was established. The presence of beta t in the HLA-A,B,C complexes is not due to cross contamination with HTA 1. However, analysis of a large scale HLA-A,B,C preparation using Coomassie blue staining shows that, under conditions of surface iodination, beta t is over-represented by a factor of about 100 times relative to beta 2 microglobulin. The significance of beta t as a minor component of HLA-A,B,C in thymus derived cells remains uncertain.