Staphylococcus aureus protein A as a means of assessing sperm penetrability in cervical mucus in vitro

Objective: The effectiveness of Staphylococcus protein A (SPA) in improving the penetration ability of sperm and reducing antisperm antibody (ASA) titers in immunologically infertile males was evaluated. Methods: Seminal fluid samples were obtained from 15 infertile men, and ASA titers were assessed with the latex agglutination test. Identification of immunoglobulin (Ig) classes and characterization of the antigens involved in the immune response were performed using indirect immunofluorescence. Local ASAs typically present as a mixture of IgG and IgA classes. The capillary tube penetration method was used to assess the capability of spermatozoa to penetrate the cervical mucus (CM). Results: ASAs associated with the neck region of sperm showed a significantly lower migration distance in the CM of infertile females than ASAs associated with the head or tail segments. ASA-positive seminal fluid exhibited significant increases in the mean migration distance (2.6 +/- 1.4 cm vs. 1.54 +/- 1.1 cm, respectively; p < 0.001) and sperm concentration (174 +/- 121.0x 10(3)/mL vs. 101 +/- 93.7 x 10(3)/mL, respectively; p=0.033) after treatment with SPA compared to pre-treated samples. A significant reduction (p < 0.01) in the recorded ASA titer was detected. Conclusion: These results indicate that SPA can be used as a sorting regimen for insemination programs. However, further studies are warranted to assess its influence on pregnancy rate.