PathwayStep6499 PathwayStep6638 PathwayStep6613 PathwayStep6667 PathwayStep6661 PathwayStep6533 PathwayStep6562 Class I MHC mediated antigen processing & presentation B Cell Activation Rap1 signalling MHC class II antigen presentation Immunoregulatory interactions between a Lymphoid and a non-Lymphoid cell Costimulation by the CD28 family TCR signaling Adaptive Immune System Adaptive immunity refers to antigen-specific immune response efficiently involved in clearing the pathogens. The adaptive immune system is comprised of B and T lymphocytes that express receptors with remarkable diversity tailored to recognize aspects of particular pathogens or antigens. During infection, dendritic cells (DC) which act as sentinels in the peripheral tissues recognize and pick up the pathogen in the form of antigenic determinants and then process these antigens and present them to T cells. These T cells of appropriate specificity respond to the antigen, and either kill the pathogen directly or secrete cytokines that will stimulate B lymphocyte response. B cells provide humoral immunity by secreting antibodies specific for the pathogen or antigen. Authored: de Bono, B, Garapati, P V, Jupe, S, May, B, 2011-05-22 Edited: de Bono, B, Garapati, P V, Jupe, S, May, B, 2011-05-22 Pubmed11861602 Pubmed16551257 Pubmed21682741 Reactome Database ID Release 431280218 Reactome, http://www.reactome.org ReactomeREACT_75774 Reviewed: Trowsdale, J, Bluestone, JA, Elliott, T, Esensten, J, Heemskerk, JW, 2011-05-28