title: CD23b isoform expression in human schistosomiasis identifies a novel subset of activated B cells.
abstract: Resistance to schistosomiasis is associated with increased levels of serum parasite-specific IgE. IgE exerts its functions through its cellular receptors, FcεRI and FcεRII/CD23; however, its functional significance in humans requires further characterization. We previously reported that increased levels of CD23(+) B cells correlate with resistance to schistosomiasis in hyperexposed populations and sought to define their potential function and relationship with IgE. We found that CD23(+) B cells are a heterogeneous cell population with functional and phenotypic differences. Circulating CD23(+) B cells are uniquely activated in schistosomiasis and express the CD23b isoform and CXCR5, the homing receptor for lymphoid follicles. High CXCR5 expression by CD23(+) B cells was associated with the capacity to home to the cognate ligand CXCL13. CD23-bound IgE cross-linking increased surface expression of CXCR5, suggesting that CD23(+) B cells home directly into the lymphoid follicles upon antigen capture. As human schistosomiasis is an intravascular parasitic infection associated with a high antigenic burden in the blood, circulating CD23(+) B cells may play a role in the capture and shuttling of antigens directly to splenic follicles, highlighting a new role for circulating B cells. This function likely plays an important role in the development of protective immunity to infection with schistosomes.
authors.affiliation: Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya.
authors.forename: Daniel
authors.initials: D
authors.lastname: Onguru
authors.forename: YanMei
authors.initials: Y
authors.lastname: Liang
authors.forename: Jennifer
authors.initials: J
authors.lastname: Elliot
authors.forename: Pauline
authors.initials: P
authors.lastname: Mwinzi
authors.forename: Lisa
authors.initials: L
authors.lastname: Ganley-Leal
mesh_terms: D000328:Adult; D000818:Animals; D016175:B-Lymphocyte Subsets / Q000276:immunology*; D002478:Cells, Cultured; D054382:Chemokine CXCL13 / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D008213:Lymphocyte Activation; D008297:Male; D008875:Middle Aged; D020033:Protein Isoforms / Q000378:metabolism; D054380:Receptors, CXCR5 / Q000096:biosynthesis / Q000378:metabolism; D017455:Receptors, IgE / Q000096:biosynthesis / Q000276:immunology* / Q000378:metabolism; D012550:Schistosoma mansoni / Q000276:immunology*; D012555:Schistosomiasis mansoni / Q000276:immunology*; D013154:Spleen / Q000276:immunology
chemical_list: C110663:CXCL13 protein, human; C095085:CXCR5 protein, human; D054382:Chemokine CXCL13; D020033:Protein Isoforms; D054380:Receptors, CXCR5; D017455:Receptors, IgE; D007073:Immunoglobulin E