Effective Delivery of Cancer Vaccines with Oxidatively Photo-Inactivated Transgenic Leishmania for Tumor Immunotherapy in Mouse Models

The parasitic protozoa in the genus of Leishmania have exceptionally favorable attributes for exploitation as a vehicle for safe and effective delivery of transgenically incorporated vaccines against infectious and malignant diseases. A dual suicidal mechanism was installed in Leishmania via genetic and chemical engineering in vitro for accumulation of photosensitizers, rendering them sensitive to dim light for inactivation. Leishmania so inactivated are non-viable, but immunologically competent to deliver vaccines for immune-prophylaxis and –therapy. We have begun to explore the utility of these Leishmania for immunization against tumors in experimental mouse models.