Betulinic Acid Amide Effect on the Immune Status of Guinea Pigs Infected With BLV

The aim of the study is to evaluate the effectiveness of immune responses in guinea pigs infected with bovine leukemia virus after administration of betulinic acid amide. The experiment was conducted on 25 guinea pigs divided into 5 groups of 5 animals each. Individuals of groups 1–4 were infected with BLV intraperitoneally with a suspension of lymphocytes isolated from a cow with leukemia. Animals of groups 1–3 were administered a betulinic acid derivative subcutaneously at a dose of 40 μg/ml: group 1 – 2 hours before infection, group 2 – 2 hours before and 7 days after infection, group 3 – 2 hours before and 7 and 14 days after pathogen inoculation. Group 4 served as a positive control (without drug administration), and group 5 – as a negative control (intact). On days 45 and 90 from the start of the experiment, blood samples were collected to assess immune status and perform direct and indirect immunofluorescence assays (IFAs). Immunological adaptations to BLV infection in guinea pigs were accompanied by a significant increase in leukocyte count by day 90 from the start of the experiment, by a factor of 1.25, as well as a 1.5- to 5.5-fold increase in lymphoid cells due to the proliferation of B-lymphocytes and cytotoxic T-lymphocytes. Administration of the experimental drug to animals prior to infection inhibited B-cell and cytotoxic T-lymphocyte proliferation, enhanced the activity of the aerobic and anaerobic bactericidal systems of neutrophils by 1.18–1.68 times, and reduced antibody titers in the indirect immunofluorescence assay. The immunomodulatory effect was most pronounced with three administrations, as confirmed by the absence of BLV in 80% of guinea pigs and a 1.86-fold decrease in the geometric mean antibody titer. These positive results suggest the potential use of betulinamide in veterinary medicine for the development of new methods for the non-specific prevention of bovine leukemia.