The immune system can initiate two kinds of adaptive immune responses: the humoral response and the cell-mediated response.
Most vaccines, currently on the market or under-development, mainly stimulate the humoral response of the immune system which is not fully effective against some pathogens (HIV, HCV, TB…): the induction of a cellular immune response may be required to more effectively treat or prevent those diseases.
Dendritic cells are the key cells of cellular immunity. They trigger immune responses by metabolizing pathogens turning them into antigens, which they will subsequently present on their surfaces to the T lymphocytes inside the lymphatic ganglions. This antigen presentation induces a specific cellular response via clonal proliferation of T lymphocytes.
Consequently, DCs have become a major target for new vaccines intended to induce a cellular immune response. However, as DCs are non-dividing, and remain therefore difficult to stimulate.