FIG. 7.

HLA-DR surface expression on transferents and their presentation of WI-1 to T cells. (A) Flow cytometric analysis of HLA-DR expression on a DR-null mutant cell line and on HLA-DR transferents described in reference 18, as illustrated by MAb L243 staining of an HLA-DR 6 transferent. An HLA-DR 15 transferent expressed an amount of DR (not shown) similar to that on HLA-DR 6 and presented antigen (see below). (B) HLA-DR transferents matched with the haplotype of the patient T-cell clones were used in antigen presentation assays. Only the HLA-DR 15 transferent presented WI-1 to noncytolytic T-cell clones K4D and K20F. nWI-1, native WI-1; APC, antigen-presenting cell.