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 macro-phages. 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. Les effets de l'interaction entre les lymphocytes de souris, les macrophages péritonéaux et les mitogènes de Mycoplasma pulmonis sur la multiplication de M. pulmonis virulentes en culture ont été étudiés. Il a été démontré une interaction directe entre les lymphocytes sensibilisés et les macrophages, en présence de M. pulmonis mitogènes inhibant non seulement la phagocytose des organismes viables, mais accroissant également la multiplication de M. pulmonis. Les cultures de macrophages associés à des lymphocytes insensibilisés de même que les cultures sporulées de macrophages n'ont pas provoqué ces résultats. On peut donc conclure que le pouvoir mycoplasmastatique ou mycoplasmacidique des macrophages péritonéaux de souris n'est pas intensifié par l'interaction entre macrophages et lymphocytes sensibilisés par les mitogènes de M. pulmonis, ni par la décharge de lymphokines.