Sperm–zona pellucida interaction and immunological infertility

Abstract

Immune reactions against gametes appear to be physiologically important for the maintenance of homeostasis in reproduction. In contrast, aberration of the immune homeostasis might give rise to 'immunological infertility'. Antisperm antibodies cause infertility by blocking fertilization. The mechanism can be explained as inhibiting the acrosome reaction of sperm by their blocking effect on capacitation through inhibiting an increase of fluidity of the sperm membrane. Autoantibodies against zona pellucida also cause infertility by blocking sperm-zona pellucida interaction, though the definitive mechanism has not been elucidated.Pretreatment of spermatozoa with D-mannnose completely inhibited sperm penetration through, but not binding to, the zona pellucida. Furthermore, very rapid kinetics between sperm extracts and D-mannnose by a BIAcore apparatus suggest that a D-mannose ligand of the sperm surface is easy to bind to and dissociate from a D-mannose residue in the sperm receptor site on the zona pellucida. Thus, D-mannnose on the human zona pellucida might be an essential molecule acting as a second sperm receptor, through which sperm penetrate into the zona pellucida.Because these antibodies appear to not cause any deleterious clinical symptoms, sperm and zona pellucida antigens are promising candidates in the development of an immunocontraceptive. (Reprod Med Biol 2006; 5: 95-104)

Survey of the year 2006 commercial optical biosensor literature

“…A number of review articles illustrate how optical biosensors, along with complementary biochemical and biophysical techniques, have furthered our understanding of protein interactions [50,[56][57][58]61,63,67,79,80,86], as well as the characterization of carbohydrates [55,78,82], oligonucleotides [91], membranes, lipids, films, and other biological interfaces [53,59,68,74,75,83,87,92]. Other reviews demonstrate the biosensor's contribution in basic research of small molecules [73] and antibodies [62,65,71,88], as well as the development of small-molecule drugs and protein therapeutics [49,52,54,89,90]. Several authors demonstrate the biosensor's escalating role in two areas: (1) food composition/contamination and environment/food safety [51,64,70,72] and (2) detection of viruses and bacteria as emerging disease elements and biological warfare agents [66,76,77,81,85].…”

Infertility and Immunocontraception based on zona pellucida

“…The authors performed careful and large-scale investigations and confirmed the existence of anti-ZP antibodies specifically reactive to human ZP proteins. They showed that the presence of anti-ZP antibodies was an etiological factor in infertility, although the incidence was very low [25]. Caudle suggested that, in a given individual, anti-ZP antibodies might coexist with other fertility disorders and that it is difficult to distinguish whether these antibodies are the real cause of concurrent fertility disorders [26].…”