Enzymic removal and re-expression of a histocompatibility antigen, HL-A 2, at the surface of human peripheral lymphocytes ( 31 Cr-labeled cells-papain-puromycin-actinomycin D).

The removal by papain of a histocompatibility antigen, HL-A 2, from the surface of intact peripheral blood lymphocytes has been examined. Up to 80% of the antigenic determinant can be removed within 90 minutes. If the cells are reincubated in nutritive medium, re-expression of HL-A 2 is complete within 6 hours. Re-expression is reversibly inhibited by puromycin (50 mug/ml), but actinomycin D (6 mug/ml) only partially inhibited re-expression after 2 hours of prior incubation with the drug.