1) Rapid generation of dendritic cells (DC) for use as anti-tumor vaccine reagents- Current protocols for the generation of dendritic cells from blood monocytes involve a variety of time-consuming physical manipulations as well as extended incubations with cytokine cocktails designed to both differentiate and mature monocyte precursors. In our group we are developing and testing a new methodology for the extremely efficient production of tumor-loaded DC, and utilizing these reagents in diseases directly relevant to dermatology- including CTCL, melanoma and squamous cell carcinoma, and potentially useful for any solid malignancy. We are presently optimizing a closed extracorporeal system for the production of DC-based vaccines in = 48 hrs and, in association with the Ag delivery system described below, will be testing this “transimmunization” procedure in pre-clinical and clinical trials.
2) Biodegradable polymers as Ag delivery vehicles for whole tumor lysates and tumor-associated Ag- One attractive strategy for next-generation vaccine development involves antigen delivery in vivo utilizing biodegradable nanoparticles (NP). Soluble macromolecules are less stable and less efficiently taken up by phagocytes such as macrophages and dendritic cells (DC) than particulate forms. Therefore, particulate systems, such as live recombinant vectors and virus-like particles, have been developed to deliver antigen to DCs in vivo. However, these vectors are often immunogenic and could be sequestered by pre-existing antibodies, as failure of recent adenovirus-based cancer and HIV vaccines illustrate. NP prepared from the biodegradable polymer poly(D, L-lactide-co-glycolide) (PLGA) can potentially overcome these delivery obstacles, since their pathogen-mimicking size and surface characteristics, as well as their biocompatibility and safety (FDA approved in humans more than 30 years), make them promising Ag delivery vehicles. NP can encapsulate a broad spectrum of macromolecules- including peptides, proteins, and cell lysates, and through an ongoing collaboration with Mark Saltzman and Tarek Fahmy of Yale Biomedical Engineering my group has optimized a system of delivering tumor-associated Ag (TAA) to DC in vitro and in vivo. We have successfully shown in human melanoma and head and neck carcinoma that NP-mediated delivery of autologous tumor lysates and TAA could optimally stimulate patient-derived CD8 T cells, an important proof-of-principle in their planned use as an immunotherapeutic vaccine. And in a project completed in association with the YCC TARE program, our group and those of Susan Kaech of Yale Immunobiology and Gil Mor of Reproductive Immunology are characterizing CD8+ circulating and tumor infiltrating T cells from epithelial ovarian cancer (EOC) patients and determining whether “tumor stem cells” can be specifically targeted with our NP reagents.