A method of generating antibodies against exogenously administered self-antigen by manipulating CD4+CD25+ regulatory T cells.

The generation of antibodies against self-antigens or antigens having a high degree of structural homology with self-antigens is a difficult task because of immunological tolerance. CD4(+)CD25(+) regulatory T cells play an important role in maintaining peripheral tolerance. Sakaguchi et al. previously reported that the transfusion of CD25(+) cell-depleted mouse splenocytes into syngeneic nude mice results in a breaking of peripheral tolerance that leads to the development of autoimmunity. In this study, we attempted to apply this mouse model to the generation of antibodies against self-antigens. We depleted CD25(+) cells from BALB/c mouse splenocytes and transferred the rest of the cells into syngeneic nude mice. The animals were immunized with mouse thyroglobulin. We observed a significant increase of the anti-mouse thyroglobulin antibody titer in the group of mice immunized twice within 10 days after the cell transfer (P<0.05). From these mice, we established hybridoma cell lines producing anti-mouse thyroglobulin monoclonal antibodies, including a clone with a dissociation constant of 10(-8)M. Control nude mice which received CD25(+) cell-containing BALB/c splenocytes did not produce anti-mouse thyroglobulin antibodies. When the CD25(-)cell-transferred nude mice were immunized with mouse Gα12, another self-antigen, anti-Gα12 antibodies were produced in the sera. This method should prove highly useful in the generation of antibodies against self-antigens or antigens for which the structure is highly conserved across species.