The study highlights the complicated relationship between anti-sperm antibodies and immunological infertility. It also draws attention to the ongoing advancements in topical ASA contraception and anti-fertility vaccines, advising on these changing health approaches.

Infertility is a disease of the reproductive system which can occur due to both male and female factors, or a combination of both. Immune infertility induced by anti-sperm antibodies (ASAs) is one such cause of infertility.

Aetiology of ASAs

In men, the aetiology of ASAs is speculated to be a result of impairment in the blood testis barrier because of trauma or infection. However, in many cases, the exact cause is not known. 

Women can develop ASAs as well, through damage to the cervical mucosa or from oral or anal intercourse with deposition of sperm into the GI tract, according to researchers writing in Vaccines. 

The mechanisms by which ASAs may lead to infertility include impaired sperm motility, impaired ability of the sperm to penetrate the cervical mucus, sperm agglutination, and impairment of the initial stages of embryo development. However, the causative mechanisms are still poorly understood and require further research.

Current controversy with ASAs

Sperm agglutination alone is not enough to diagnose immunological infertility, explain the authors of a review on ASA testing and male immunological infertility, but its presence may signify the existence of ASAs.

Furthermore, evidence to support the treatment of immunological infertility using steroids or intrauterine insemination is weak. This has created a wide range of protocols among physicians, with some clinics scrapping ASA testing in the preliminary phase of evaluation of male infertility, while others still use the testing routinely, offering treatment options that may not be based on proper evidence. 

Anti-fertility vaccines

As noted in the review article in Vaccines, the development of an anti-sperm vaccine for men is challenging due to the sheer number of spermatozoa present in the male reproductive tract.

The anti-sperm vaccines currently in development achieve their effect via IgA secretion in the prostate, which leads to the creation of antibodies in the male reproductive tract. At present, a number of anti-fertility vaccines are being used successfully to reduce fertility in experimental models.

Topical contraception using ASAs

A very interesting area of current research involving ASAs is that of contraception.[4] Passive immunity by means of introducing antibodies to the vaginal canal is not a new concept and has been studied using HIV and HSV-2. However, the use of ASAs applied vaginally for contraception has only more recently been the subject of research. 

Human contraception antibody (HCA) has been created using IgM anti-sperm mAb. The variable sequence of this antibody was combined with invariant IgG1 sequences to produce an IgG1 mAb. Preclinical testing of this antibody demonstrated sperm agglutination activity as well as sperm immobilisation in the presence of complement, and a phase 1 clinical trial is currently underway.

Disclaimer: This story is contributed by Courtney Manser and is a part of our Global Content Initiative, where we feature selected stories from our Global network which we believe would be most useful and informative to our doctor members.