Effects on fertility of immunizing mice with anti-idiotypic antibodies to porcine zona pellucida antigen

OBJECTIVE: To evaluate the effects on fertility by immunization with anti-idiotypic antibodies to porcine zona pellucida (PZP) antigen. METHOD: Anti-idiotypic antibodies (Ab(2)) were produced in New Zealand rabbits immunized with 17D3 monoclonal antibodies (mAbs) (IgG, Ab(1)) to PZP antigen. The antisera were first passed through immuno-affinity chromatography column linked to normal mouse IgG so as to remove the antibody bound to normal mouse IgG The passing elute was then purified by immuno-affinity chromatography using 17D3 mAbs to get the Ab(2). Female BALB/c mice, 5-week-old, were grouped and immunized with the Ab(2), PZP antigen, target antigen of the Ab(1) and normal rabbit IgG, respectively. The treated female mice were mated with male BALB/c mice and sacrificed at gestation day 10. Analyses included ELISA measurement of anti-ZP antibody titer, fetal number determination and evaluation of ovarian histomorphology. RESULTS: The Ab(2) appeared as a single protein band by SDS-PAGE. Shown by a competitive inhibition ELISA, the Ab(2) specifically bound to the variable region of the 17D3 Ab(1). Compared with controls, the female mice immunized with Ab(2) showed a decreased pregnancy rate and a statistically significant reduction in fetal numbers. Histological examination of ovaries demonstrated that Ab(2) exposure interfered less with follicular development than did exposure to PZP. CONCLUSION: Immunization of female mice with Ab(2) to PZP mAbs suppresses fertility and fetal numbers with minimal ovarian pathology.