Expression of TAP 1, TAP 2, and HLA class I in HD-derived cell lines. Five H-RS lines plus an LCL and BL cell line from donor DH were analyzed by Western blotting for expression of TAP 1 and TAP 2 (A). Viable cells from the H-RS cell lines plus an LCL were also analyzed by FACScan for surface expression of HLA class I using the MoAb W6/32 (B). Clear profile, staining with second step antibody alone; shaded profile, W6/32 staining. Results shown are representative of those observed in several repeated assays.