The role of individual spleen cells in the interferon response of the intact mouse.

A method is described for the detection of interferon production by individual spleen cells of mice after intravenous virus infection. Although mouse spleen plays a major role in the total interferon response to Newcastle disease virus, the number of spleen cells participating is a small fraction of the total, suggesting that interferon formation is to some extent a specialized cell function. Monolayers of mouse embryo cells, after brief contact with agar-suspended spleen cells from interferon-producing mice, have roughly circular foci of cells remaining after removal of agar and vesicular stomatitis virus challenge. The numbers of such foci correlate directly with the number of spleen cells, concentration of inducing virus in the inoculum, duration of contact of cells with mouse-embryo indicator monolayers, time after interferon induction, and serum interferon titer. With this technique, evolution of the interferon-forming cell response in spleens of virus-infected mice has been studied.