CD1dhiCD5+ B cells differentiate into antibody-secreting cells under the stimulation with calreticulin fragment

Abstract

Calreticulin (CRT) is a multifunctional molecule in both intracellular and extracellular environment. We have previously found that a recombinant CRT fragment (rCRT/39-272) could modulate T cell-mediated immunity in mice via activation and expansion of CD1dhiCD5+ B cells as well as induction of CRT-specific regulatory antibodies. Antibody secreting cells (ASCs) are terminally differentiated B cells responsible for producing antibodies to participate in positive immune response as well as immune regulation. In this study, we demonstrate that rCRT/39-272 differentiates murine CD1dhiCD5+ B cells into ASCs marked by increased expression of plasma cell-associated transcription factors and production of polyreactive antibodies against DNA and CRT in vitro. Intraperitoneal administration of rCRT/39-272 augmented differentiation of CD1dhiCD5+ B cells into ASCs in naïve mice or mice with experimental autoimmune encephalomyelitis. Thus, we propose that ASC differentiation and subsequent antibody production of CD1dhiCD5+ B cells are key steps in CRT-mediated immunoregulation on inflammatory T cell responses. © 2013 Higher Education Press and Springer-Verlag Berlin Heidelberg.