A dissociated induction of MCF-producing and MAF-producing T cells specific for <em>Listeria monocytogenes</em> in the <em>in vitro</em> primary culture system.

Using an in vitro primary culture system which we had previously established, the induction phase of Listeria monocytogenes-specific effector cells was analysed with respect to their abilities to produce effector lymphokines, macrophage chemotactic factor (MCF) and macrophage-activating factor (MAF). Listeria-specific effector cells generated after in vitro culture of normal spleen cells with viable L. monocytogenes for 5 days conveyed L3T4⁺, Lyt-2 , Thy-1⁺ surface antigens and produced MCF and MAF in response to the secondary stimulation with heat-killed L. monocytogenes. The cells required for the induction of Listeria-specific effector cells, which produce effector lymphokines, MCF and MAF, were L3T4⁺, Lyt-2^-, Thy-1⁺ cells. The kinetic analysis revealed that the ability of these effector cells to produce MCF was generated earlier than that to produce MAF. Furthermore, using passive transfer of cells, the effector cells producing only MCF, which were generated early in culture, conferred delayed-type hypersensitivity (DTH) alone, but MCF- and MAF-producing effector cells generated late in culture conferred sufficient levels of DTH and acquired cellular resistance (ACR). These results indicate a dissociated production of MCF and MAF by L. rnonocytogenes-specific T cells generated in the primary in vitro culture system. [ABSTRACT FROM AUTHOR]