In male mice of the strains FVB/N (haplotype H-2q) and 129/Sv (haplotype H-2b) aged 6-7 months, estimated indicators of the functioning of the thymus, bone marrow, spleen, pineal gland and adrenal glands, the number of CD3+ (Tlymphocytes ) and CD11b+ (macrophages) cells in the brain, and also studied the characteristics of changes in the values of indicators after administration of neurotoxin 1-methyl4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) to such mice (reproduction of parkinsonism). We have found that in intact mice of the FVB/N strain the thymulin level in the blood and the mass and cellularity of the thymus are lower, and the number of CD3+ cells, colony-forming progenitor cells for fibroblasts and granulocytes-macrophages in the bone marrow are greater than in mice of the 129/Sv strain. The number of CD3+ and CD11b+ cells in the brain of FVB/N strain mice exceeds their value in 129/Sv strain mice by 1.6 and 2.2 times, respectively. The level of melatonin in the blood of mice of the FVB/N strain was 2.4 times lower than in mice of the 129/Sv strain, while the mass of the adrenal glands was greater. The in vitro experiments have shown a decrease of the thymulin level in the supernatant of the cultured thymus stroma after incubation with corticosterone in mice of the 129/ Sv strain (from 5.8 ± 0.6 to 3.8 ± 0.4, log2) and no changes in the indicator in mice of the FVB/N strain. 18 days after MPTP administration there was a drop in the blood thymulin level, in the mass and cellularity of the spleen in mice of the 129/Sv strain, a decrease in the mass and cellularity of the thymus in mice of both strains, and an increase in the mass of the adrenal glands in mice of the FVB/N strain. Under the influence of the neurotoxin, the proportion of CD3+ cells in the brain of mice of the FVB/N strain has significantly increased compared to the control group, while in the mice of the 129/Sv strain the proportion of CD11b+ cells has increased significantly. Thus, the haplotype H-2 of mice has affected the functioning of the central and peripheral organs of the immune and endocrine systems, the number of T-lymphocytes and macrophages in the brain as well as the manifestations of changes in indicators after MFTP administration, which may be important for the formation of feature of morphofunctional disorders in the nervous system in such animals.