Antiacrosin antibodies and infertility. II. Gene immunization with human proacrosin to assess the effect of immunity toward proacrosin/acrosin upon protein activities and animal fertility

ObjectiveTo assess the effect of antiacrosin antibodies upon proacrosin/acrosin activities and animal fertility.DesignProspective study.SettingBasic research laboratory.Patient(s)A gene immunization (GI) model was developed; mice were injected with the sequence encoding human proacrosin (h-proacrosin), cloned in an expression vector.Intervention(s)Subcloning of h-proacrosin in a eukaryotic expression vector (promoter, CMV; leader sequence, α-1 antitrypsin; pSF2-Acro); GI of female mice with this plasmid.Main Outcome Measure(s)The following parameters were evaluated: [1] adequate conditions for GI protocols, [2] humoral response to GI with pSF2-Acro, [3] protein regions recognized by the antibodies, and [4] effect of antibodies upon proacrosin/acrosin–ZPA binding and amidase activity, and animal fertility.Result(s)Conditions of female mice GI with the proacrosin sequence were established (plasmid purification with anion exchange chromatography and 40 μg of pSF2-Acro per dose) to trigger an immune response, reaching maximum levels at week 9 after the first injection. Antibodies produced by GI recognized human and mouse sperm acrosin systems, inhibited human proacrosin/acrosin interaction with recombinant human ZPA and protease activity, and negatively affected mouse IVF and early embryonic development. In addition, mice immunized with SF2-Acro exhibited a significantly lower size of fetuses.Conclusion(s)Antiacrosin antibodies developed by using GI inhibit human proacrosin/acrosin activities and impair mouse fertility.