Suppression of Ehrlich subcutaneous solid tumor growth by immunization with ganglioside GT1b of its origin, its IgM antibody or anti-idiotype antibody.

Mice vaccinated with purified Ehrlich tumor-plasma GT1b admixed with Freund's adjuvant suppressed subcutaneous growth of the same tumor cells inoculated in vivo by 37.9%. The suppression was dose-dependent and was a result of humoral immune response against GT1b. Further, when mice were injected with varying doses of rabbit polyclonal anti-GT1b IgM antibody and challenged with Ehrlich tumor cells subcutaneously, a significant reduction in tumor growth (47.3%) was observed. Again, the suppression was dose-dependent. To strengthen furthier the observed therapeutic potential of this immunogenic GT1b, mice were immunized with anti-idiotype antibodies to GT1b raised in female Sprague Dawley rats by immunization with rabbit anti-GT1b IgM, which is expected to carry the structural image of GT1b. Immunization of mice with this anti-idiotype antibody was observed to suppress Ehrlich subcutaneous solid tumor growth by 60%. The results indicated therapeutic potential of immunogenic tumor-associated ganglioside in solid tumor model.