Reduction of fertility in male mice immunised with pSG.SS.C3d3.YL.Bin1b recombinant vaccine

Objectives: To study the anti-fertility effect of a DNA vaccine using Bin1b as the target antigen in male mice.

Methods: A novel recombinant eukaryotic vector containing a fusion gene sequence of mouse Bin1b in tandem with three copies of C3d fragment (C3d3) was used to construct pSG.SS.C3d3.YL.Bin1b. The correct expression of the Bin1b-C3d3 protein was confirmed in transfected HEK293 cells by indirect immunofluorescence and western blot analysis. The fertility of immunised mice was determined by a mating experiment and sperm motility test. Anti-Bin1b antibody titres in sera were examined by ELISA assays. Binding activity of C3d3 fragment of the fusion protein was verified in C3d receptor-expressing Raji cells and flow cytometric analysis.

Results: Immunisation of pSG.SS.C3d3.YL.Bin1b recombinant DNA vaccine significantly decreased sperm motility and compromised fertility in male mice. ELISA results showed that the titres of anti-Bin1b IgG in sera of immunised mice increased markedly with the immunisation process. Further, the anti-fertility effect of pSG.SS.C3d3.YL.Bin1b was significantly better than that of pSG.SS.YL.Bin1b DNA vaccine and generated higher titres of anti-Bin1b antibody.

Conclusions: Our results show that recombinant DNA vaccine targeting Bin1b can markedly reduce fertility in male mice, providing an alternative approach for birth control.