ABLE 11-2 PROPERTIES OF THYMUS-DEPENDENT AND THYMUS-INDEPENDENT ANTIGENS Tl an Property TD antigens Ty pe 1 Type 2 Chemical nature Soluble protein Bacterial cell-wall Polymeric protein antigens components(e g. LPS) capsular polysaccharides Humoral response Isotype switching Yes Limited Affinity maturation Yes No Immunologic memory Polyclonal activation Yes(high doses ITA ABLE 11-7 COMPARISON OF NAIVE AND MEMORY B CELLS Properties Naive B cell Memory B cell Membrane markers Immunoglobulin IgM, IgD IgM, IgD(?), IgG, IgA, IgE Complement receptor L High Anatomic location Spl Bone marrow, lymph node, spleen Life span Short-lived May be long-lived Recirculation Receptor aflinity Lower average affinity Higher average affinity due to affinity maturation Adhesion molecules Low ICAM-1 High ICAM-I "Allinity maturation results from somatic mutation during proliferation of centroblasts and subsequent antigen selection of centrocytes bearing high-afinity mlg