The protein nature of the Thy-1.2 alloantigen as expressed by the murin lymphoblastoid line S-49.1 TB-2-3.

This preliminary study was undertaken to investigate the chemical nature of the Thy-1.2 antigen expressed on the murine cell line S-49.1 TB-2-3 (S-49). The presence of the Thy-1.2 antigen was indicated by the inhibition of AKR anti-C3-Thy-1.2 serum induced lysis of 51Cr-primed target cells. It was found that limited digestion of S-49 cells with crude papain yielded a Thy-1.2-containing solution. The protein nature of the Thy-1.2 antigen obtained in this manner was indicated by changes after proteolytic digestion. Separate digestions with crystalline papain, insolubilized papain, and insolubilized protease all destroyed the Thy-1.2 activity. These results suggest that the protein moiety is necessary for Thy-1.2 activity.