Interactions of mycoplasmas with lymphocytes and macrophages.

The effects of interactions between mouse lymphocytes, peritoneal macrophages and Mycoplasma pulmonis mitogens on the growth of infective M. pulmonis in infected cultures were studied. Lymphocytes transformed into blast cells following in vitro exposure to either M. pulmonis mitogens or concanavalin A supported the multiplication of M. pulmonis to a greater extent than did unsensitized lymphocytes. Mitogenic stimulation of lymphocytes by M. pulmonis did not induce the release in vitro of lymphokines capable of enhancing the killing of infective organisms by mouse peritoneal macrophages. In addition, it has been shown that direct interactions of sensitized lymphocytes with macrophages in the presence of M. pulmonis mitogens not only did not enhance phagocytosis of the infecting organisms, but rather provided improved culture conditions for the replication of M. pulmonis as compared to cultures of macrophages with unsensitized lymphocytes or macrophages cultured alone. It can therefore be concluded that mycoplasmastatic or mycoplasmacidic capacities of mouse peritoneal macrophages are not enhanced due to the interactions of macrophages with lymphocytes sensitized by M. pulmonis mitogens.