Immunoplacental therapy, a potential multi-epitope cancer vaccine

Abstract

The field of tumor immunology has made great advancements in recent years. A retrospective analysis of previous vaccine strategies combined with present knowledge may provide additional insight in this treatment modality. This article provides a review of immunoplacental therapy (IPT), a cancer vaccine consisting of chorionic villi extractions from the human placenta after a live full-term delivery. This therapy was first introduced in the 1970s by Valentin I. Govallo, M.D., Ph.D., who noted the immunological similarities between pregnancy and cancer. The goal of cancer immunotherapy, according to Govallo, is to view the fetal allograft as an "impregnating tumor" and create an immunological state in the oncological patient analogous to a spontaneous abortion in a pregnant women. The placenta shares identical growth mechanisms, antigenic determinants, and immune-escape properties with cancer cells; this includes numerous tumor-associated antigens, angiogenic growth factors, complement regulatory proteins, and defective apoptotic mechanisms which aid in their survival. Placental vaccination may function as a multi-epitope vaccine; the body recognizes the placental antigens of this vaccine as foreign, and thus stimulates a cross reactive humoral and cell-mediated immune response targeting cancer tumor-associated antigens as well as proteins that aid in cancer angiogenesis, complement regulation, and apoptotic resistance. With recent advancements in molecular and cellular cancer immunology, the model introduced by Govallo may provide an important strategic approach to cancer immunotherapy.