title: Rotavirus-specific CD5+ B cells in young children exhibit a distinct antibody repertoire compared with CD5- B cells.
abstract: Antiviral antibody responses in infants are limited in quality. One reason for this finding could be that the majority of B cells in infants are CD5+ cells, a subset of B cells that is thought to contain cells expressing polyreactive, low-affinity B cell receptors. We analyzed the rotavirus (RV)-specific antibody heavy chain variable region (VH) repertoire in CD5+ and CD5- B cells of four RV-infected children between 10 and 19 months of age. We found that the RV-specific B cell repertoire in CD5+ cells was VH3 family biased, in contrast to the VH1/VH4 dominance seen in CD5- B cells. The immunodominant RV-specific gene segment in CD5- B cells was VH1-46, which is the dominant segment used in RV-specific peripheral blood B cells from infants and adults. In contrast, the immunodominant gene segment was VH3-23 in RV-specific CD5+ B cells, which is the dominant gene segment in randomly selected B cells. Both RV-specific CD5+ and RV-specific CD5- B cells from all children studied demonstrated very low frequencies of somatic mutations. In conclusion, CD5+ B cells in infants responding to RV use an antibody gene repertoire that differs from the virus-specific repertoire of CD5- B cells, and both CD5+ and CD5- RV-specific B cells exhibit a low frequency of somatic mutations.
authors.affiliation: Department of Pediatrics, Vanderbilt University Medical Center, and Monroe Carell Jr. Children's Hospital at Vanderbilt, Division of Neonatology, Nashville, TN 37232-9544, USA. hendrik.weitkamp@vanderbilt.edu
authors.forename: Jörn-Hendrik
authors.initials: JH
authors.lastname: Weitkamp
authors.forename: Bonnie J
authors.initials: BJ
authors.lastname: Lafleur
authors.forename: James E
authors.initials: JE
authors.lastname: Crowe
mesh_terms: D000914:Antibodies, Viral / Q000235:genetics*; D000917:Antibody Formation / Q000235:genetics*; D016175:B-Lymphocyte Subsets / Q000276:immunology*; D001483:Base Sequence; D018956:CD5 Antigens / Q000032:analysis*; D022801:Complementarity Determining Regions / Q000235:genetics; D005260:Female; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000235:genetics; D007135:Immunoglobulin Variable Region / Q000235:genetics; D007223:Infant; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation; D012401:Rotavirus / Q000276:immunology*; D012400:Rotavirus Infections / Q000235:genetics / Q000276:immunology*
chemical_list: D000914:Antibodies, Viral; D018956:CD5 Antigens; D022801:Complementarity Determining Regions; D007143:Immunoglobulin Heavy Chains; D007135:Immunoglobulin Variable Region