The Third Cell Type Required for the Immune Response of Spleen Cells in vitro

Abstract

Abstract Cells that adhere to glass or plastic surfaces, obtained from spleens of nor mal and immunized mice, were compared for the ability to interact synergistically with nonadherent cells in the in vitro response to sheep erythrocytes. Adherent cells obtained from normal and immunized mice were equally x-ray resistant at several levels of x-irradiation and equally effective in enhancing the response of nonadherent cells. The plaque-forming cell response of cultures that contained dilutions of adherent cells from immunized mice were equivalent to responses of cultures containing corresponding dilutions of normal adherent cells. Adherent cells, therefore, did not appear to increase in number or change in function following in vivo antigenic stimulation. Adherent cells, whether derived from normal or immunized mice, were required for the in vitro response of non-adherent cells obtained from immunized animals. Spleen cell cultures obtained from immunized mice, however, required higher dilutions of non-adherent cells to interact synergistically with adherent cells. The enhanced responsiveness of non-adherent cells from immunized mice was consistent with an increase in number or change in function of non-adherent cells as a result of antigenic stimulation in vivo.