SummaryIntraperitoneal injection of (BALB/c × C57BL/6) F1 mice with live, but not killedSalmonella enteritidis11RX (11RX) induced T cells in the spleen and peritoneal cavity which were able to proliferatein vitroin response to two different forms of 11RX antigens. The majority of cells which proliferated were L3T4+T cells and most of the response was restricted by theI‐Alocus of theH‐2major histocompatibility complex, although a smallerKregion restricted response was also detected. T cells able to respond to 11RX antigens could only be demonstrated when non‐adherent lymphoid cell suspensions from immunized mice were used, and usually a limited response was obtained unless small numbers of adherent cells present in normal peritoneal cell suspensions were added. Cells culturedin vitrofor 3 days were able to mediate local transfer of delayed type hypersensitivity and secondary immunization did not enhance the reactivity of responding cells to 11RX antigens.