An association between actin and the major histocompatibility antigen H-2

P815 cells spontaneously shed material (exfoliate) in which actin is the major protein. The exfoliate also contains H-2. The association between actin and H-2 is stable even in the presence of detergent, indicating that protein-protein interactions exist between the actin and H-2. The exfoliate probably consists of highly purified microvilli.