Retinoic acid (RA) is known to have several functions that lead to a potent mucosal IgA response. Nevertheless, its exact role in human IgA synthesis has yet to be elucidated. Thus, we investigated the role of RA in promoting IgA isotype switching in human B cells. We found that RA increased IgA production and the expression of germ-line IgA1 and IgA2 transcripts (GLTα1 and GLTα2). This induction occurred alongside an increase in the frequency of IgA1-secreting B cell clones, as assessed by limiting dilution analysis. Under the same conditions, RA did not increase IgM and IgG production. Am80, an agonist of RA receptor α (RARα), increased IgA production. In addition, RA activity was abrogated by LE540, an antagonist of RAR, suggesting that the RAR pathway is involved in RA-induced IgA production. Taken together, these results indicate that RA induces IgA isotype switching mainly through RARα in human B cells.
Bibliographical noteFunding Information:
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea Government (MEST) (No. 2013R1A1A2008536 to P.H.K. and No. 2011-0014492 to G.Y.S.). Studies were carried out in the Institute of Bioscience and Biotechnology at Kangwon National University.
All Science Journal Classification (ASJC) codes
- Immunology and Allergy