Impaired HLA-class-I stability in a sarcoma cell line which stimulates exclusively HLA-class-II-restricted autologous T cells

Defects in the generation and transport of antigenic peptides within tumor cells will lead to the expression of unstable HLA-class-I molecules on the cell surface. These defects will allow tumor cells to escape an MHC-class-I-restricted T-cell response. Recently, we described an exclusively HLA-class-II-restricted autologous T-cell response against a human sarcoma cell line MZ-MES-1 in vitro. Here, we show that surface HLA-class-I molecules of MZ-MES-1 cells are unstable at physiological temperature. HLA-class-I surface expression of MZ-MES-1 cells could be strongly enhanced by culture at low temperature in contrast to various other cell lines analyzed in parallel. Furthermore, culture at l…