Requirement for a bone marrow-derived component in the expression of cell-mediated antibacterial immunity

Mice were X irradiated with 400 R and 1 week post-irradiation were found to be unable to develop antilisterial immunity after active or passive immunization with immunologically committed spleen lymphocytes from Listeria-immune donors. This consequence of irradiation disappeared spontaneously within 21 days of exposure to X rays. Mice irradiated with as much as 900 R could be passively protected by immunologically committed lymphoid cells from Listeria-immune donors 10 days after irradiation if they had been given normal bone marrow cells on the day or irradiation. It is concluded that, in addition to immunologically committed lymphocytes, a second cellular component is needed for the expression of antibacterial immunity. This second component is bone marrow derived.