Conjugation of immunogenic fraction separated from microbial cells of BCG strain with stimulating component proved to be a promising direction in the creation of antituberculosis drugs. One of such components is KIM-M2, a complex of thermostable soluble antigens extracted from microbial cells of BCG strain incubated with formalin and conjugated with polyvinyl pyrrolidone and polyethyleneglycol. To study the impact of KIM-M2 on the morphology of lymph nodes, spleen, lungs and liver of guinea pigs, the animals of group 1 (control, n = 5) were injected subcutaneously with a virulent culture of M. bovis strain 8 at a dose of 0.001 mg/ml. Animals of group 2 (n = 5 subjects) were injected subcutaneously with KIM-M2 at a dose of 0.5 mg/ml of protein, then 30 days later they were injected with a virulent culture of M. bovis strain 8, subcutaneously at a dose of 0.001 mg/ml. Animals of group 3 (n = 5 subjects) were injected subcutaneously with a virulent culture of M. bovis strain 8 at a dose of 0.001 mg/ml, 14 days later they were injected with KIM-M2 at a dose of 0.5 mg/ml of protein. Histomorphologic changes in animals of group 1 can be considered as morphological equivalent of immune suppression reaction. At the same time, the animals from group 2 and especially from experimental group 3 showed an increase of immunogenesis that can be proved by a profound proliferation of lymphocytes and macrophages.