Fig. 1.

Tapasin influences HLA class I surface expression. (A) HLA expression levels in .220 cells before and after tapasin reconstitution were measured by flow cytometry using anti-FLAG mAb. MFI, median fluorescent intensity. Data for tapasin-positive cells represent the average MFI for R240 and T240 tapasin-expressing cells. (B) TD for each HLA allotype, defined as the ratio of MFI of tapasin-positive over tapasin-negative cells, is shown in log₁₀ scale. Error bars correspond to SDs calculated from multiple measurements as described in Methods.