Effect of T-activin on Cellular Immune Response in Balb/c Mice with L-5178-y Lymphoma

T-activin is a complex of immunologically active peptides (MW 1.2-6 KDa) derived from the thymuses of different animal species. To study immunomodulatory and antitumor effect of T-activin and its relation with type 1 and type 2 cytokines, immunosuppressed mice with L-5178-Y lymphoma were treated with subcutaneous T-activin. T-activin treatment increased life span and reduced the increase in body weight observed in lymphoma-bearing mice. Effect of T-activin on cellular immune response was evaluated with delayed hypersensitivity test to DNFB and splenic lymphoproliferative response. Both depressed immune response to DNFB and depressed proliferative response observed in lymphoma-bearing mice were totally reverted with T-activin treatment to values observed in control mice treated. In order to know the relation between the above results and cytokine production and T cell subsets, concentrations of IFN- and IL-4 in culture supernatants were determined by ELISA and T cell subsets were determined using flow cytometric analysis. Recovery was not observed in IL-4 levels but complete recovery was observed in IFN- levels. On the other hand, T-activin reversed the lymphoma-induced increment of CD4+ T cells and with this the CD4/CD8 ratio was restored to control value. These findings suggest that the mechanism through which T-activin exerts its antitumor effect is by inducing a type 1 response through IFN- production, thereby promoting cellular immune response.