Capacitated sperm cells react with different types of antisperm antibodies than fresh ejaculated sperm

Abstract

To determine if sera of some women have antibodies against capacitated but not freshly ejaculated sperm. The sera of 66 women undergoing in vitro fertilization (IVF) were tested for sperm antibodies after 1 hour and 18 hours of sperm incubation in the maternal sera. Subsequently, 5 sera were tested with capacitated versus noncapacitated sperm cells. The study was carried out in a university hospital department. The patients were 66 consecutive couples undergoing IVF. Sera and semen that were taken for routine tests as part of the IVF procedures were used. A case with IVF failure associated with late appearance of sperm antibodies prompted us to study the detection of sperm antibodies after 1 hour and 18 hours incubation. Of 37 cases negative for sperm antibodies after 1 hour incubation, 7 demonstrated high levels of antibodies after 18 hours incubation. In 21 of 23 cases with low or intermediate levels of antibodies after 1 hour incubation, significantly higher levels (P less than 0.05) of antibodies were found after 18 hours. Different and higher levels of sperm antibodies were observed in five sera after incubation of 1 hour with capacitated sperm as compared with noncapacitated controls. Major antigenic differences may exist between capacitated and noncapacitated sperm. In some women sperm antibodies are reactive against capacitated sperm only. This has no certain clinical significance but may explain certain cases of IVF failure, unexplained infertility, and part of the variation in sperm antibodies testing methods.