Activin A stimulates IgA expression in mouse B cells.
In this study, a potential role for activin A in mouse immunoglobulin (Ig) regulation was investigated. We observed that activin A increased IgA secretion in B lymphoma cells. In contrast, little effect was observed on IgM and IgG2b secretion. Activin A also significantly increased surface IgA expression and Ig germ-line alpha transcript (GLT(alpha)) levels. In parallel, activin A increased GLT(alpha) and post-switch transcripts alpha (PST(alpha)) expression in normal B cells, which was augmented by IL-5. An increase in IgA production by surface IgA negative B cells by activin A was apparent. Finally, the increase of IgA secretion by activin A was blocked by an activin receptor inhibitor (SB431542). The increase of GLT(alpha) by activin A was augmented by Smad3/4 overexpression and abolished by Smad3 dominant negative overexpression. These results suggest that activin A induces IgA isotype switching via Smad3/4-mediated germ line alpha transcription.
Lee
Hwa-Joung
HJ
Department of Molecular Bioscience, School of Bioscience & Biotechnology, Kangwon National University, Chunchon 200-701, Republic of Korea.
Seo
Goo-Young
GY
Kim
Hyun-A
HA
Kim
Pyeung-Hyeun
PH
D028341:Activins / Q000008:administration & dosage*; D000818:Animals; D001402:B-Lymphocytes / Q000187:drug effects / Q000378:metabolism*; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D015870:Gene Expression / Q000187:drug effects / Q000502:physiology; D007070:Immunoglobulin A / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*
D007070:Immunoglobulin A; C422405:activin A; D028341:Activins