Abstract

In addition to the standard therapies of chemotherapies and surgical interventions, viral therapy for tumor treatment has provided a new option for cancer patients. Whether the effects are safe, however, remains to be fully evaluated. Accordingly, we explored the immunological mechanisms of viral action against the H₂₂ ascitic tumor, using both the Newcastle disease virus (NDV) and the parainfluenza virus (PIV). We measured IL-2 levels, NK (Natural killer) cell activity, lymphocyte proliferation rates, and the CD4⁺/CD8⁺ cell numbers' ratio. All indicators were superior in the virus-treatment group compared with the control group. Tumor cells infected by either virus induced the expression of the tumor-associated antigen, which stimulated the host immune system.

Key words:Immunologic mechanism, tumor immunity, viral immunotherapy, tumor-associated antigen.