Western blot analysis with MoAb TP25.99 of HLA class I heavy chains immunoprecipitated with MoAb W6/32 from RBC-30, RBC-5, W-RBC, LD-RBC, and PLT (lanes 1, 2, 3, 4, 5, respectively) and from PBMC lysate as control (lane 6). Densitometric analysis of the bands is shown in the lower panel.