title: Long-term maintenance of polysaccharide-specific antibodies by IgM-secreting cells.
abstract: Many bacteria-associated polysaccharides induce long-lived Ab responses that protect against pathogenic microorganisms. The maintenance of polysaccharide-specific Ab titers may be due to long-lived plasma cells or ongoing Ag-driven B cell activation due to polysaccharide persistence. BALB/c and V(H)J558.3 transgenic mice respond to α1→3-dextran (DEX) by generating a peak anti-DEX response at 7 d, followed by maintenance of serum Ab levels for up to 150 d. Analysis of the cellular response to DEX identified a population of short-lived, cyclophosphamide-sensitive DEX-specific plasmablasts in the spleen, and a quiescent, cyclophosphamide-resistant DEX-specific Ab-secreting population in the bone marrow. BrdU pulse-chase experiments demonstrated the longevity of the DEX-specific Ab-secreting population in the bone marrow. Splenic DEX-specific plasmablasts were located in the red pulp with persisting DEX-associated CD11c(+) dendritic cells 90 d after immunization, whereas DEX was not detected in the bone marrow after 28 d. Selective depletion of short-lived DEX-specific plasmablasts and memory B1b B cells using cyclophosphamide and anti-CD20 treatment had a minimal impact on the maintenance of serum anti-DEX Abs. Collectively, these findings demonstrate that the maintenance of serum polysaccharide-specific Abs is the result of continuous Ag-driven formation of short-lived plasmablasts in the spleen and a quiescent population of Ab-secreting cells maintained in the bone marrow for a long duration.
authors: Department of Microbiology, University of Alabama, Birmingham, AL 35294, USA.
authors: Jeremy B
authors: JB
authors: Foote
authors: Tamer I
authors: TI
authors: Mahmoud
authors: Andre M
authors: AM
authors: Vale
authors: John F
authors: JF
authors: Kearney
mesh_terms: D000818:Animals; D000918:Antibody Specificity / Q000187:drug effects / Q000502:physiology*; D001853:Bone Marrow / Q000276:immunology / Q000378:metabolism; D039521:CD11c Antigen / Q000276:immunology; D003911:Dextrans / Q000276:immunology* / Q000494:pharmacology; D007114:Immunization; D007075:Immunoglobulin M / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D007156:Immunologic Memory / Q000187:drug effects / Q000502:physiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008822:Mice, Transgenic; D010950:Plasma Cells / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D013154:Spleen / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D013997:Time Factors
chemical_list: D039521:CD11c Antigen; D003911:Dextrans; D007075:Immunoglobulin M