HLA antigen expression on uveal melanoma cells in vivo and in vitro

Immunotherapy with cytokines may be an additional option in the treatment of primary uveal melanoma or melanoma metastases. A study of the effect of cytokines on cultured uveal melanoma cells may predict the effect that cytokines may have in vivo. Knowledge about the influence of cytokines on HLA expression may be especially beneficial, as HLA expression is essential for immune recognition. However, little is known about the normal expression of the HLA antigens on uveal melanoma cells in tissue culture. We therefore determined the HLA expression on short-term cultures of uveal melanoma cells and compared the results to the expression on tissue sections of the original tumors. In vivo and in vitro expression of the monomorphic HLA class I determinants and of HLA-A (R = 0.77) correlated well. A slightly lower agreement was observed for expression of HLA-B (R = 0.68). In vitro growth was associated with a decrease in expression of the class II determinant HLA-DR. We conclude that expression of HLA class I on cultured melanoma cells corresponds to the expression on the original tumor, allowing the applicability of cultured cells as predictors of responsiveness to cytokines in vivo.