Monocytes as a Cellular Vaccine Platform to Induce Antitumor Immunity

We recently developed a monocyte-based cellular vaccine platform for cancer treatment. In contrast to the traditional utilization of monocytes as precursors to generate dendritic cells (DC) for vaccination purposes, we find that freshly isolated monocytes with no differentiation process can be loaded with tumor antigens (Ag) and trigger robust antitumor cytotoxic T lymphocyte (CTL) responses. In this chapter, we describe methods to prepare, administer, and evaluate murine Ly-6C^hi monocyte-based cellular vaccines for their therapeutic efficacy. This includes procedures for isolation, purity determination, Ag loading, administration of bone marrow (BM)-derived monocytes, as well as methods to determine vaccine efficacy through the examination of Ag-specific CD8⁺ T cell expansion and antitumor responses in murine melanoma models. As a vaccine platform, undifferentiated monocytes can be easily adapted to different tumor models with a multitude of target antigens. The method described here seeks to facilitate preclinical research of monocyte-based vaccination as a strategy for cancer immunotherapy.