Mitogen responses and interferon production after exposure of human macrophages to infectious and inactivated influenza viruses.

Human macrophages were exposed to two influenza A viruses representing different subtypes. The donors were likely to have been exposed to one subtype (H3N2) but not to the other (H0N 1). Similar effects upon the macrophages were observed for both subtypes: macrophage enhancement of mitogen-stimulated lymphocyte transformation responses was depressed, and the macrophages produced interferon. In contrast, macrophages exposed to inactivated virus exhibited normal enhancement of lymphocyte transformation response, yet produced interferon, although in lower titers than did macrophages exposed to infectious virus.