Quantitative isolation of mouse thymus leukemia antigen, TL.

This report describes the purification of TL from papain digests of a tumor line (ASL1) and of an established cell line (L251A). Through the use of gel filtration and ion-exchange chromatography, the TL was purified approximately 100-fold with respect to the original digest. It was noted that the TL isolated from ASL1 had a specific activity 1.4 times higher than that isolated from L251A. The reason for this anomaly is unexplained. However, this work indicates that classical methods of protein chemistry can be used in the purification of these membrane components which are present in only small amounts on the cell surface.