Structural analysis of thymus-leukemia (TL) antigens in the mouse

Thymus-leukemia (TL) antigens have been sequentially immunoprecipitated from glycoprotein pools prepared from lysates of biosynthetically labeled ASL-1w leukemia cells with a monoclonal antibody and a standard alloantiserum. Results suggest that on leukemia cells from Tlaa mice, as previously reported for thymocytes from these mice, all the alloantiserum-defined TL specificities (TL.1, 2, 3, 5, 6) as well as the specificity defined by the monoclonal antibody (TL.m3) are carried by a single molecular species. The degree of structural homology between the 45,000-m.w. heavy chains of TL and H-2 was investigated by the technique of comparative tryptic peptide mapping. Results indicate that TL is more distantly related at the primary structural level to H-2 than H-2 antigens are to one another.