The aim of the study is to evaluate the functional state of the aerobic and anaerobic bactericidal systems of neutrophils in guinea pigs treated with experimental conjugates of BCG antigens with betulinic and betulonic acids after infection with Mycobacterium smegmatis. The experiment was conducted on 20 guinea pigs, divided into 4 groups of 5 animals each. Individuals of groups 1–3 were infected with M. smegmatis subcutaneously at a dose of 5 mg/ml. Then, 14 days later, animals of group 2 were administered a conjugate of BCG antigens with betulinic acid subcutaneously at a dose of 0.5 ml, and animals of group 3 were administered a conjugate of BCG antigens with betulonic acid subcutaneously at the same dose. The control group consisted of intact guinea pigs. On the 14th, 28th and 42nd days from the start of the experiment, blood samples were taken to perform an indirect immunofluorescence reaction (IIFR) and assess the functional state of neutrophils. The studies revealed that infection of animals with M. smegmatis enhances the activity of intracellular bactericidal components of neutrophils, as evidenced by a significant increase in the average cytochemical coefficient (ACC) of cationic proteins from days 14 to 28 by 30–53 % and the ACC of myeloperoxidase by 16–62.5 % throughout the entire experiment. Both experimental conjugates exerted an additional stimulating effect on the function of intracellular antibacterial components of phagocytes, promoting the rapid elimination of mycobacteria 14 days after drug administration, as confirmed by the results of the IIFR. The BCG antigen conjugate with betulonic acid, compared to the betulinic acid-only preparation, exhibited a more pronounced effect on myeloperoxidase enzymatic activity both 14 and 28 days after administration. Thus, the positive results suggest the potential use of these experimental preparations in veterinary medicine for the prevention and treatment of mycobacterioses caused by rapidly growing non-tuberculous mycobacteria.
Vlasenko et al. (Thu,) studied this question.