INDUCTION OF A TUMOR-SPECIFIC CELLULAR-IM MUNITY BY IDIOTYPE-VACCINATION WITH THE MAB OC 125 FOR PATIENTS WITH OVARIAN CARCINOMAS

The concept of the oncological immnunotherapy is the induction of a ce llular antitumoral immunity by the modification of the tumor-host-inte raction. The network-structure of the immune system implicates the pos sibility of a selective immunization by the activation of the ''idioty pic cascade.'' The alternative approach is to initiate the idiotypic n etwork utilizing antibodies (named Ab1) against a tumor-associated ant igen (TAA), which induces the production of anti-idiotypic-antibodies (Ab2beta), mimicking the ''internal image'' of the tumor-associated an tigen. The principle is to transform the critical epitope of the TAA i nto an idiotypic determinant expressing the mirror image of the tumor- associated antigen on the surface of the antigen binding region of an antibody. The Ab1 may induce Ab2, which then are able to induce Id + ( Ab1+)B cells or Id+ T(H) cells, by the new antigen presentation and th e formation of the so-called MHC-associated ''idiopeptides.'' Our eval uation should demonstrate the induction of anti-tumoral immunity after the activation of the idiotypic network. In a retrospective analysis we evaluated the immunological reaction pattern by the leucocyte migra tion inhibition assay against autologous tumor material. In 82 % of th e patients, we detected a significant induction of a cellular immunity . Summarizing, we see a beneficial role of the induction of the idioty pic-network against a tumor-associated antigen showing delayed clinica l courses of the disease after vaccination of the patients with antibo dy-fragments of the OC 125, demonstrating a new and powerful way of a therapeutical influence on the immune system.