The activation of peritoneal macrophages in the course of primary
infection of mice with attenuated strain of Francisella tularensis is associated with 2.5 fold increase in spontaneous
INT reductase activity on day 5 after the immunization. The splenic cells of immunized mice pulsed in vitro by specific
antigen secrete lymphokine that is able to induce an increase in spontaneous
INT reductase activity of resident peritoneal cells. The production of spontaneous
superoxide anion by peritoneal phagocytes reaches the highest level on day 5 after the immunization. It does not correlate with the results of cytotoxic or phagocytic activities at this time interval. An enhanced
superoxide dismutase activity precedes an increase of
superoxide anion secretion. The production of
hydrogen peroxide is rising till day 7 and is related to the cytotoxic activity of peritoneal phagocytes. Concerning the testing of F. tularensis
antigen as immunization agent, no changes of oxidative metabolism were detected. This might be in connection with the insufficient protection effect of killed F. tularensis
vaccine. The production of reactive
oxygen metabolites, probably under the control of
superoxide dismutase, together with secreted
lymphokines during the first days after the
infection may play a regulatory role in the induction of immune response against intracellular pathogen F. tularensis.