Gamma-interferon upregulates transferrin receptors and decreases membrane microviscosity in K562 cells.

We investigated the effect of gamma-interferon (gamma-IFN) on three cellular parameters: cell membrane fluidity and expression of two antigens that have been associated with cell proliferation, namely transferrin receptor (Tf-R: a cell surface protein) and Ki-67 antigen (Ki-67: a nuclear protein). We observed small, yet significant changes in the first two parameters, but not the third parameter. These were investigated in K562 cells, a human chronic myelocytic leukemia cell line. These results suggest that the microviscosity changes and the surface Tf-R density were closely associated, and that gamma-IFN was involved in increasing proliferative activity of the cells by decreasing membrane fluidity and upregulating Tf-R expression.