Loss of HLA-C locus specificities from stored lymphocytes and de novo synthesis following incubation at 37 degrees C.

Abstract

The variable expression of the C locus specificities at the cell surface is a major problem in HLA typing and the phenomenon was clearly documented by the International Cell Exchange Program. In contrast with HLA-A and -B, the C locus specificities are readily lost from cells following storage at room temperature for a few days or in overnight incubation at 37 degrees C in the presence of protein synthesis inhibitors. These specificities can be made to reappear by making the cells metabolize at 37 degrees C for 8 to 20 h in nutrient medium. Sixty-nine per cent of the positive C locus reactions lost after 7-day storage at room temperature were recovered after overnight incubation at 37 degrees C. The reappearance was dependent on protein synthesis since presence of cyclohexamide during incubation completely blocked the recovery. A simple overnight incubation is very useful in enhancing C locus expression on older cells.