Antigen-Presenting Cell/Tumour Cell Hybrid Vaccines in Cancer Immunotherapy

Abstract

In recent years, there has been a considerable interest in the development of immuno-therapeutic approaches for treating cancers, including strategies for inducing antigen-specific cytotoxic T cells (CTLs) capable of killing tumour cells in situ. These approaches include both the active induction of CTLs by vaccination of tumour bearing patients, and the ex vivo expansion of tumour-specific CTLs for adoptive cellular transfer. One promising approach has been through the generation of hybrid cells, formed by fusion of professional antigen presenting cells (pAPCs) with tumour cells expressing relevant tumour associated antigens. Dendritic cells (DCs) represent the most potent form of pAPCs, and have been widely used in the generation of APC/tumour cell hybrid vac-cines, in the context of a range of tumour types. Studies of fusion cell vaccines in animals have demonstrated not only the induction of tumour-specific CTLs, but also protection against subsequent tumour challenge and regression of established tumours. Results of clinical trials in patients have been less dramatic, but have shown the ability of hybrid vaccines to induce tumour-specific T cell responses, in some instances associated with disease stabilization or tumour regression. In addition to dendritic cell fusion vaccines, a number of non-DC fusion vaccines have been described.