title: IL-10 production by B cells expressing CD5 with the alternative exon 1B.
abstract: B lymphocytes are divided into two subpopulations, B1 and B2 cells based on expression of the T cell-associated protein CD5. Natural B1 cells are further divided into B1a cells that express CD5 on their membrane and B1b cells that do not but share most other biological characteristics of B1a cells. Recent studies from our laboratory have revealed, in humans, the existence of two alternative isoforms of the CD5 protein. A cell surface CD5 isoform which uses exon 1A (E1A) of the gene in B1a cells, and an intracellular isoform which uses exon 1B (E1B) mainly in human B1b cells. Indeed, the protein isoform encoded by transcripts containing E1B lack the leader peptide and is, thus, retained in the cytoplasm of B cells. The restriction of interleukin (IL)-10 to B1 lymphocytes in the mouse raises the possibility that the human CD5-E1B-expressing B cells produce IL-10. This prediction was confirmed in the CD5 negative Jok-1 B cells transfected with cDNA for either isoforms resulted in high level IL-10 production. Our data indicate that E1B-CD5-expressing B cells have the capacity to interfere with the immune response through their ability to produce high levels of IL-10.
authors.affiliation: EA2216 Immunology and Pathology IFR 148, Université Européenne de Bretagne, France.
authors.forename: Soizic
authors.initials: S
authors.lastname: Garaud
authors.forename: Christelle
authors.initials: C
authors.lastname: Le Dantec
authors.forename: Agnès Revol
authors.initials: AR
authors.lastname: de Mendoza
authors.forename: Rizgar A
authors.initials: RA
authors.lastname: Mageed
authors.forename: Pierre
authors.initials: P
authors.lastname: Youinou
authors.forename: Yves
authors.initials: Y
authors.lastname: Renaudineau
mesh_terms: D017398:Alternative Splicing; D015703:Antigens, CD / Q000378:metabolism; D000945:Antigens, Differentiation, T-Lymphocyte / Q000378:metabolism; D001402:B-Lymphocytes / Q000378:metabolism*; D051940:B7-2 Antigen / Q000378:metabolism; D015153:Blotting, Western; D018956:CD5 Antigens / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D004797:Enzyme-Linked Immunosorbent Assay; D005091:Exons / Q000235:genetics; D005434:Flow Cytometry; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D016753:Interleukin-10 / Q000235:genetics / Q000378:metabolism*; D037181:Lectins, C-Type; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection; D000099192:CD69 Antigens
chemical_list: D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D051940:B7-2 Antigen; D018956:CD5 Antigens; D049452:Green Fluorescent Proteins; D016753:Interleukin-10; D037181:Lectins, C-Type; D020033:Protein Isoforms; D011993:Recombinant Fusion Proteins; D000099192:CD69 Antigens