Biochemical characterization of the T-cell alloantigen RT-6.2.

This study presents the partial molecular characterization of the alloantigenic rat T-cell marker RT-6. In contrast to most lymphocyte surface membrane proteins, RT-6 proved to be resistant to short-term (15 min) solubilization by TX-100 at 4 degrees, but could be efficiently solubilized by long-term (16 hr) exposure at 4 degrees or short-term (15 min) exposure at 37 degrees. SDS-PAGE analyses of RT-6.2 immunoprecipitates under non-reducing conditions revealed two bands with apparent molecular weights of 21,000 and 24,000 (25,000 and 28,000 under reducing conditions). Radiolabelled sugars failed to be incorporated metabolically into RT-6.2, neither endoglycosidase-F and 0-glycanase digestion nor NaOH treatment caused any detectable decrease in the molecular weight of RT-6.2, and RT-6.2 failed to bind to any of a series of agarose-coupled lectins with a wide of sugar-binding specificities. These observations suggest that RT-6.2 may lack carbohydrate moieties.