On the contrary, anti-sperm immune response is part and parcel of coitus. Since reproductive immunology is just not part of the mainstream, its practitioners occupy a fringe space within the field, publishing in their own niche journals like Journal of Reproductive Immunology, American Journal of Reproductive Immunology or Placenta, etc. It’s not surprising then that findings that convulse this sub-field and turn long-held notions upside down are simply not well-known outside the niche. Such is the case with anti-sperm immune responses.
In my analysis, three women scientists, Sarah Robertson, Ashley Moffett and B. Anne Croy, have revolutionized reproductive immunology over the last few decades, upending long-held dogmas that never really fit with actual data anyway. Sarah Robertson is at the Robinson Research Institute, School of Paediatrics and Reproductive Health, University of Adelaide, Adelaide, SA, Australia.
Robertson and others showed that post-intercourse anti-seminal fluid immune response is a normal part of female reproductive tract physiology. This would be jarring only if we considered immune response synonymous with inflammation and in turn inflammation synonymous with damage. That’s far from the truth. Normal post-intercourse anti-seminal fluid immune response consists largely of immune cells with regulatory function. As such they damage neither sperm, seminal fluid nor the female reproductive tract. In fact, Robertson even proposes that proper ‘priming’ of female anti-seminal fluid immune response is important for a healthy pregnancy ().
Rather than presence/absence of anti-seminal fluid/sperm immune response, type of immune response distinguishes a healthy from an unhealthy female reproductive tract. Seminal fluid itself helps shape regulatory type responses against itself. Not just in humans but also in rodents and livestock, seminal fluid is one of the body’s richest sources of TGF-beta (Transforming Growth Factor-beta; TGF-b1, -b2, -b3) and prostaglandins (2, 3). This suggests they are evolutionarily highly conserved features of seminal fluid in general. In turn, such molecules are essential for conditioning T cells to differentiate towards regulatory function (, Tregs). We can also construe presence of such cells in female reproductive tract is important by the fact that women with recurrent miscarriages have far fewer anti-sperm Tregs (4).
1. Robertson, Sarah A., John J. Bromfield, and Kelton P. Tremellen. “Seminal ‘priming’ for protection from pre-eclampsia—a unifying hypothesis.” Journal of reproductive immunology 59.2 (2003): 253-265.
2. Kelly, R. W., and H. O. Critchley. “Immunomodulation by human seminal plasma: a benefit for spermatozoon and pathogen?.” Human Reproduction 12.10 (1997): 2200-2207.
3. Robertson, Sarah A., et al. “Transforming growth factor β—a mediator of immune deviation in seminal plasma.” Journal of reproductive immunology 57.1 (2002): 109-128.
4. Liu, Chaodong, Xian-Zhong Wang, and Xin-Bo Sun. “Assessment of sperm antigen specific T regulatory cells in women with recurrent miscarriage.” Early human development 89.2 (2013): 95-100.