Proliferation and autoantibody production by mouse thyroglobulin (MTg)-specific B cells activated in vitro by MTg and MTg-specific T cells.

Immunization of genetically susceptible strains of mice with mouse thyroglobulin (MTg) and adjuvant results in sensitization of MTg-specific CD4+ T cells that can induce experimental autoimmune thyroiditis (EAT) after in vitro activation with MTg. These MTg specific CD4+ T cells also provide help to MTg-specific B cells which produce anti-MTg autoantibodies in vivo. This study was undertaken to develop a system with which to measure MTg-specific helper function in vitro. MTg-activated T cells were shown to provide help to MTg-primed B cells in vitro as assessed by B-cell proliferation and anti-MTg autoantibody production. These responses were MTg-specific and required MTg priming of both the T- and B-cell populations. An MTg-specific CD4+ T-cell line also induced MTg-specific B-cell proliferation and was capable of inducing IgG1, IgG2a and IgG2b synthesis in MTg- primed B cells.