CpG-oligodeoxynucleotides stimulate immunoglobulin A secretion in intestinal mucosal B cells.
Bacterial DNA motifs (such as CpG-oligodeoxynucleotides: CpG-ODN) induce innate immune responses via binding to Toll-like-receptor-9 (TLR-9). In murine intestinal mucosa treatment with CpG-ODN worsens chronic intestinal inflammation, whereas it prevents or ameliorates colitis when given in a prophylactic setting. In tonsils B cells have been reported to express TLR-9, especially after activation. Whether B cells in the human intestinal mucosa also express TLR-9 and whether their function can be influenced by CpG-ODN is, so far, unknown. Mucosal B cells were isolated according to a new protocol from surgical specimens of patients with inflammatory bowel disease and from controls by collagenase digestion followed by magnetic cell sorting using anti-CD19 antibody armed magnetic beads. TLR-9 mRNA and protein expression were quantified by real-time polymerase chain reaction (PCR) and Western blot, respectively. Immunoglobulin A (IgA) secretion was measured by enzyme-linked immunosorbent assay after stimulation of isolated B cells with CpG-ODN, control GpC-ODN or lipopolysaccharide (LPS). Flow cytometric analysis of the isolated lamina propria mononuclear cells showed a purification of 73% (+/-22%) CD19(+) cells. By quantitative reverse transcription-PCR and by Western blot TLR-9 expression in this cell population was evident. IgA secretion was increased significantly by CpG-ODN incubation compared with GpC-ODN and LPS. Compared with unstimulated controls, CpG-ODN up-regulated IgA secretion to 139% (+/-21%). These data demonstrate that CD19(+) mucosal B cells express TLR-9 and secrete increased levels of IgA upon stimulation with CpG-ODN, indicating an additional link between adaptive and innate intestinal immune responses.
Blaas
S H
SH
Department of Internal Medicine I, University of Regensburg, Regensburg, Germany. stefan.blaas@klinik.uni-regensburg.de
Stieber-Gunckel
M
M
Falk
W
W
Obermeier
F
F
Rogler
G
G
D018941:Antigens, CD19 / Q000276:immunology; D001402:B-Lymphocytes / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism; D015153:Blotting, Western / Q000379:methods; D015704:CD4 Antigens / Q000032:analysis; D002469:Cell Separation / Q000379:methods; D002478:Cells, Cultured; D003106:Colon / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005434:Flow Cytometry; D006801:Humans; D007113:Immunity, Innate; D007070:Immunoglobulin A / Q000032:analysis / Q000276:immunology*; D007413:Intestinal Mucosa / Q000276:immunology*; D008070:Lipopolysaccharides / Q000494:pharmacology; D009838:Oligodeoxyribonucleotides / Q000494:pharmacology*; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D013268:Stimulation, Chemical; D051217:Toll-Like Receptor 9 / Q000032:analysis / Q000235:genetics
D018941:Antigens, CD19; D015704:CD4 Antigens; C408982:CPG-oligonucleotide; D007070:Immunoglobulin A; D008070:Lipopolysaccharides; D009838:Oligodeoxyribonucleotides; D012333:RNA, Messenger; D051217:Toll-Like Receptor 9