title: Human anti-pneumococcal polysaccharide antibodies are secreted by the CD5- B cell lineage.
abstract: To determine whether human antibody responses to T cell-independent pneumococcal polysaccharide antigens are derived from CD5+ or CD5- B cells, we utilized an ELISPOT assay to detect individual anti-polysaccharide antibody-secreting cells. Human anti-type IV pneumococcal polysaccharide antibody-secreting cells were found in the CD5- B cell subpopulation. An EBV transformed anti-pneumococcal antibody-secreting B cell line was also CD5-. The ontogeny of CD5 expressing B cells correlated with the age at which polysaccharide responsiveness is acquired (generally around age 2 years in humans). The CD5- B cell subset represents only 25-30% of the B cells in young children, but this fraction increases throughout childhood to a plateau of 70-80% of the B cells in adults. These results support the hypothesis that the developmental change in responsiveness to T cell-independent polysaccharide antigens in humans is associated with maturation of the CD5- B cell subset.
authors.affiliation: Department of Pediatrics, University of Florida, College of Medicine, Gainesville 32610.
authors.forename: D J
authors.initials: DJ
authors.lastname: Barrett
authors.forename: J W
authors.initials: JW
authors.lastname: Sleasman
authors.forename: D A
authors.initials: DA
authors.lastname: Schatz
authors.forename: M
authors.initials: M
authors.lastname: Steinitz
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000907:Antibodies, Bacterial / Q000096:biosynthesis*; D015703:Antigens, CD / Q000032:analysis*; D018951:Antigens, CD20; D000944:Antigens, Differentiation, B-Lymphocyte / Q000032:analysis; D001402:B-Lymphocytes / Q000276:immunology*; D018956:CD5 Antigens; D002648:Child; D002675:Child, Preschool; D006801:Humans; D007114:Immunization; D007223:Infant; D007231:Infant, Newborn; D008875:Middle Aged; D011135:Polysaccharides, Bacterial / Q000276:immunology*; D013296:Streptococcus pneumoniae / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D015703:Antigens, CD; D018951:Antigens, CD20; D000944:Antigens, Differentiation, B-Lymphocyte; D018956:CD5 Antigens; D011135:Polysaccharides, Bacterial