ABSTRACT
Dendritic cells, one of the most potent of the antigen-presenting cells (APCs), have a unique ability to induce primary immune responses against microbial infection (1). They also play a major role in acquired immune responses (2). Immature dendritic cells capture antigen and then migrate to regional lymph nodes where they develop into mature cells. Mature APC are then able to activate antigenspecific naïve lymphocytes. Immature dendritic cells express low levels of major histocompatibility complex (MHC) class II, CD83, and costimulatory molecules such as CD80 (B7-1), CD86 (B7-2), and CD40; mature dendritic cells are characterized by high expression levels of these marker molecules (3,4). These cells may be thought of as architects of immunity (5). Dendritic cells not only present antigen extremely efficiently, determining the magnitude of the immune response, but also influence the quality of the response, contribute to deletional tolerance, promote cross-priming, and may be important in downregulation of effector responses and the maintenance of memory (6).
