In this work the effect of the natural complex of cytokines on the generation of active forms of oxygen (AFO) by mouse peritoneal macrophage in different in vivo and in vitro systems were studied. Intact mice of various strains were found to have differences in the AFO production of their macrophages: BALB/c (H-2d) > CBA (H-2k) > C57BL/6 (H-2b), as well as in the degree of the prestimulation of the macrophage oxygen metabolism with the complex of cytokines BALB/c > CBA. The in vivo and in vitro infection of macrophages of mice, oppositely reacting to Leishmania donovani, led to the gradual suppression of the capacity of macrophages for AFO generation. The preliminary introduction of the complex of immunocytokines into mice before their infection led to a decrease in AFO generation by macrophages of resistant strains CBA and C57BL/6 and its enhancement by macrophages of the sensitive strain BALB/c.