B-1a B cells constitute a special B cell population with distinct ontogenic, phenotypic, and functional features. Through the production of polyreactive natural antibodies, B-1a B cells exert a central role in immune-system homeostasis. B-1a B cells can also present antigens to naïve T cells, thus controlling their activation and differentiation into different T cell linages (Th1, Th17 or Regulatory T cells). Our laboratory was pioneer in showing that B-1a B cells exert a dual role in controlling T cell differentiation in the context of pregnancy. Using an animal model of pregnancy disturbances, we recently demonstrated that B-1a B cells from animals suffering pregnancy complications induce the differentiation of naïve T cells into pro-inflammatory Th1 and Th17 T cells. Notably, B-1a B cells from animals undergoing normal pregnancies not only fail to induce pro-inflammatory T cell differentiation but strongly inhibit it.
The aim of this project is to further investigate this dual capacity of the B-1a B cells in the context of pregnancy making special emphasis on the possible mechanisms.