INTERFERON MODULATES CELL STRUCTURE AND FUNCTION

ABSTRACT Interferon treatment alters the structure of the plasma membrane and the cytoskeleton in a variety of cells. These structural changes are associated with modulation of specific functions in human epidermoid carcinoma (HeLa-S3) cells, human skin fibroblasts (FS-4 and ME), transformed mouse fibroblasts (L-929), and thioglycolate-elicited mouse peritoneal macrophages, all treated with homologous beta interferon. The rigidity of the plasma membrane lipid bilayer is increased within 30 min from the beginning of treatment of HeLa cells growing in suspension, but returns tc control level within a few hr. The rigidity increases again by 24 hr after beginning of treatment and persists. Increased abundance of submembranous actin filaments in interferon-treated HeLa-S3 cells is associated with impairment of the mobility and the endocytosis of receptor-bound concanavalin A, slowing of cell proliferation, increased cell size, and increased frequency of multinucleated cells. In interferon-treated human fibroblasts, increased organization of actin-containing microfilaments into bundles is associated with decreased cell locomotion, membrane ruffling, and intracellular movement of organelles, with prolongation of the intermitotic interval, increased cell size, and increased frequency of abortive mitosis giving rise to multinucleated cells. Increased organization of microfilaments in mouse L-929 cells is associated with a marked rise in the frequency of abortive mitoses.