Antigen presentation in vaccine development.

A variety of microorganisms, nutrients or toxins are generally intrude our body through mucosal tissues or skin, where equipment for both preventing their invasions and catching their information to activate internal immune systems for adapting surroundings is arranged. Among the equipment, cells in charge of innate immunity, particularly dendritic cells (DCs), having an excellent capacity for prompt recognition of invaded pathogens via toll-like receptors (TLRs) to alert B and T cells for establishing aquired/adaptive immunity by presenting their processed antigenic fragments, have been paid great attention. These TLR-activated, antigen captured DCs are divided into two groups; one is pathogen-retaining unit and the other is pathogen-controlling unit. The latter DCs present processed antigenic molecules from the pathogens to competent alphabeta T cells together with special containers, such as class I, class II MHC and CD1 to generate specific cellular immunity. The former two MHC molecules can present processed peptide antigens, whereas the last CD1 molecule can present glycolipid/lipid antigens. In contrast, B lymphocytes that captured antigens via their specific immunoglobulin (Ig) receptors present digested peptide fragments with their class II MHC to stimulate suitable CD4(+) helper T cells which in turn secrete various cytokines to efficiently expand and maintain antibody production from that partner B cells to establish humoral immunity. These alphabeta T cells and antibodies, recognize either processed antigenic peptide or glycolipid fragments, and thus, identification of these epitopes enables us to generate artificial pathogen-specific vaccines. Based on the recent findings about precise mechanisms of antigen processing and presentation orchestrated at the surface compartment, future development of vaccines against various pathogens are discussed.