Development of an Antigen Delivery System for a B Cell-Targeted Vaccine as an Alternative to Dendritic Cell-Targeted Vaccines

Vaccines have contributed to the prevention of infectious diseases for a long time. Pathogen-derived antigens and adjuvants in vaccine formulations stimulate immune cells to elicit humoral and cellular immune responses against pathogens. Achieving highly immune responses with decreased adverse effects requires the development of a system that can deliver antigens to specific immune cells. Dendritic cells (DCs) are well-known professional antigen presenting cells (APCs) that initiate acquired immune responses by presenting antigens to T cells. Accordingly, DC-targeted vaccines have been investigated and applied in clinical trials for the treatment of infectious diseases and for chronic diseases such as cancers. In addition to DCs, B lymphocytes are regarded as professional APCs despite their primary role in humoral immunity. Therefore, B cell-targeted vaccines are also expected to elicit both humoral and cellular immune responses. In this review we summarize the basic functions of DCs and B cells as APCs. We also provide information on DC and B cell targeted vaccines in preclinical and clinical settings. Finally, we introduce our novel antigen delivery system that targets splenic marginal zone B cells and the ability of this system to act as a novel vaccine that elicits both humoral and cellular immune responses.