RESUMO
AIM: To evaluate the effect of B. subtilis IMV B-7724 lectin on the functional activity of macrophages (Mph), natural killer (NK) cells and cytotoxic lymphocytes (CTL) of mice bearing Lewis lung carcinoma (LLC). MATERIALS AND METHODS: The studies were performed on C57Bl/6J mice; LLC was used as an experimental transplantable tumor. The lectin from B. subtilis IMV B-7724 was administered to LLC-bearing mice subcutaneously at a dose of 1 mg/kg of body weight for 10 days. The immunological testing was performed on days 14, 21, and 28 after tumor grafting. The cytotoxic activity of Mph, NK, and CTL was estimated in MTT-assay; the content of the stable metabolites of nitric oxide (NO) was measured by a standard Griess reaction; the arginase activity (Arg) was determined based on the measurement of urea. RESULTS: The administration of the B. subtilis IMV B-7724 lectin to LLC-bearing mice exerted its antitumor and antimetastatic effects partially via a significant (p < 0.05) increase of Mph and NK activities after the completion of the treatment. In the group of animals injected with lectin, the NO/Arg ratio increased significantly, indicating the prevalence of Mph with proinflammatory and antitumor properties. The cytotoxic activity of Mph exceeded the indices of untreated mice and intact control by 1.8 times and 5.3 times respectively; of NK - by 2.8 and 1.3 times respectively. The effect of treatment on the CTL activity was less pronounced. CONCLUSION: Antitumor and antimetastatic activity of the lectin from B. subtilis IMV B-7724 ensured the preservation of the cytotoxic activity of the main effectors of antitumor immunity (Mph, NK, and CTL) throughout LLC growth.