Interferon-γInduced Expression of Class I HLA Antigens on K-562 Cells Grown in Serum-Free Medium

Abstract

Human interferon-γ (IFN-γ), encoded in Escherichia coli by recombinant human DNA, induces the expression of HLA antigens in the pluripotent hematopoietic stem cell line K-562 grown in serum-free growth medium. Expression was noted in 90% of the cells within 4 days and there was a high density of expression per cell, as determined by cytofluorography. Upon subculture, the cells rapidly lose their ability to express HLA, indicating that the continued presence of IFN-γ is necessary for the expression. Reinduction of expression with IFN-γ occurs in a high percentage of cells (up to 90%), which is comparable to the induction in freshly treated control cells.