Aim: To clarify the subsets and location of B cells responsible for the production of natural anti-keratin autoantibody (AK auto Ab), and analyze the function of each subset.
Methods: Cells isolated from spleen and peritoneal cavity of C57BL/6 mice were cultured in vitro. FACS was employed to detect keratin reactive B cell subsets. The anti-keratin IgM level in supernatant was analyzed by ELISA, while ELISPOT was utilized to detect the B cells which can secrete AK auto Ab.
Results: Keratin reactive B cells were mainly marginal zone B cells in spleen, while they were mainly B-1a cells in peritoneal cavity. There were more B cells producing AK auto Ab in peritoneal cavity than in spleen. The anti-keratin IgM level in the supernatant of cultured peritoneal cells was much higher than that of splenocytes.
Conclusion: There are three subsets of keratin-reactive B cells: B-1 B cells, follicular B cells and marginal zone B cells. B-1 B cells are active in secreting AK auto Ab.