Activity Test of Silkworm (Tubifex sp.) on Lymphocyte Proliferation and Interleukin-2 Levels as an Immunostimulatory Agent

Background: Infection remains a health problem that requires strengthening the immune response. Lymphocytes are important components of the adaptive immune system, while IL-2 plays a role in lymphocyte activation and proliferation. Silkworm (Tubifex sp.) contains amino acids and bioactive compounds that have potential immunomodulatory activity, making it a promising natural material for supporting infection therapy. Objective: To analyze the activity of silkworm extract on lymphocyte proliferation and Interleukin-2 (IL-2) levels in male rats as indicators of immunostimulatory activity. Methods: This experimental study used silkworm extract at several doses. Lymphocyte proliferation activity was evaluated using the MTT assay by measuring absorbance and determining the EC50, while serum IL-2 levels were measured using the ELISA method with a microplate reader at a wavelength of 450 nm. Results: Silkworm extract increased IL-2 levels in a dose-dependent manner. IL-2 levels at doses of 50, 100, 200, and 400 mg/kg BW were 415.31 ± 2.52, 506.52 ± 3.01, 623.11 ± 3.02, and 766.01 ± 3.24 pg/mL, respectively, which were higher than the negative control (194.73 ± 8.02 pg/mL). In the lymphocyte proliferation assay, the EC50 value of silkworm extract was 4.327 µg/mL, close to that of Imboost® (4.182 µg/mL). The absorbance value of the silkworm extract also increased from 0.383 ± 0.05 at a concentration of 3.125 µg/mL to 0.502 ± 0.01 at 25 µg/mL. Conclusion: The results indicate that silkworm extract has potential as a natural immunostimulatory/immunomodulatory agent by increasing lymphocyte proliferation and IL-2 levels.