Immunomagnetic separation of antibody-labelled from antibody-free human spermatozoa as a treatment for immunologic infertility. A preliminary report

Bovine reproductive immunoinfertility: pathogenesis and immunotherapy

Infertility is one of the primary factors for cattle reproduction in the present scenario. Reproduction-related immunoinfertility mainly involves immunization against the antigens related to reproductive hormones (LHRH, GnRH, Gonadal steroids, PGF2α and oxytocin), spermatozoa, seminal plasma and ovum. Anovulation, delayed ovulation, sperm immobilization, failure of fertilization, prolonged uterine involution, extended calving interval, prolonged post-partum estrus and reduced conception rate could be a result of immunoinfertility that occur due to the blockage of receptor site by antibodies formed against hormones, sperm and ovum. Immunoinfertility can be treated in the animal by giving sexual rest to females, by using various reproductive technologies such as in-vitro fertilization, gamete intra fallopian tube transfer, and intracytoplasmic sperm injection, sperm washing and by treating the animals with immunomodulators such as LPS, Oyster glycogen, etc. This review summarizes the different causes of bovine reproductive immunoinfertility and amelioration strategies to overcome it.

Sex difference in anti-sperm antibodies

Background

Some diseases have sex differences. There have been no reports on the relationship between anti-sperm antibodies (ASA) and sex differences.

Methods

ASA are detected by sperm-immobilization test using patients' sera in women. In men, the ASA testing is generally performed by direct-immunobead test.

Main findings

Sperm-immobilizing antibodies in women inhibit sperm migration in their genital tract and exert inhibitory effects on fertilization. ASA bound to sperm surface in men also show inhibitory effect on sperm passage through cervical mucus. The fertilization rate of IVF significantly decreased when sperm were coated with higher numbers of ASA. For women with the antibodies, it is important to assess individual patients' SI50 titers. In patients with continuously high SI50 titers, pregnancy can be obtained only by IVF. For men with abnormal fertilizing ability by ASA, it is necessary to select intracytoplasmic sperm injection. Production of sperm-immobilizing antibodies is likely to occur in women with particular HLA after exposure to sperm. The risk factors for ASA production in men are still controversial.

Conclusion

Attention to sex differences in specimens, test methods and the diagnosis of ASA should be paid. For patients with ASA, treatment strategies have been established by considering sex difference for each.

Utility of magnetic cell separation as a molecular sperm preparation technique

Assisted reproductive techniques (ARTs) have become the treatment of choice in many cases of infertility; however, the current success rates of these procedures remain suboptimal. Programmed cell death (apoptosis) most likely contributes to failed ART and to the decrease in sperm quality after cryopreservation. There is a likelihood that some sperm selected for ART will display features of apoptosis despite their normal appearance, which may be partially responsible for the low fertilization and implantation rates seen with ART. One of the features of apoptosis is the externalization of phosphatidylserine (PS) residues, which are normally present on the inner leaflet of the sperm plasma membrane. Colloidal superparamagnetic microbeads ( approximately 50 nm in diameter) conjugated with annexin V bind to PS and are used to separate dead and apoptotic spermatozoa by magnetic-activated cell sorting (MACS). Cells with externalized PS will bind to these microbeads, whereas nonapoptotic cells with intact membranes do not bind and could be used during ARTs. We have conducted a series of experiments to investigate whether the MACS technology could be used to improve ART outcomes. Our results clearly indicate that integrating MACS as a part of sperm preparation techniques will improve semen quality and cryosurvival rates by eliminating apoptotic sperm. Nonapoptotic spermatozoa prepared by MACS display higher quality in terms of routine sperm parameters and apoptosis markers. The higher sperm quality is represented by an increased oocyte penetration potential and cryosurvival rates. Thus, the selection of nonapoptotic spermatozoa by MACS should be considered to enhance ART success rates.

Antisperm antibodies: etiology, pathogenesis, diagnosis, and treatment

OBJECTIVE

To critically review the English-language literature and describe the current diagnosis, prevalence, etiology, and treatment of antisperm antibodies (ASA).

DESIGN

A comprehensive literature search of the English-language literature published between 1966 and December 1997 was performed on MEDLINE. Articles were also located via bibliographies of published works.

RESULT(S)

Data were excerpted from articles identified by MEDLINE search. The diagnosis, prevalence, etiology, and treatment of ASA are described.

CONCLUSION(S)

There is sufficient evidence that ASA impair fertility in couples with unexplained infertility. A number of different methodologies are available, which may be used in their detection. However, in many cases, test interpretation is subjective. Although there is not enough evidence to support systemic treatment for ASA, application of a variety of assisted reproductive technologies improves outcome.

Infertility due to antisperm antibodies

Immunoinfertility is an important problem, involving a significant number of infertile couples. Although the presence of antibodies on sperm has better prognostic value than those in serum or seminal plasma, it may not be the sole authentic evidence of immunoinfertility. Infertility from antisperm antibodies is likely only when they bind to a relevant sperm antigen involved in a specific fertility function. The variance in functional deficits seen in immunologic infertility is most likely related to antibodies directed at different sperm antigens or different class, subclass, or isotypes. Antibodies to FA-1 seem to be of significant importance in human immunoinfertility. In approaching couples with infertility, a high index of suspicion for antibodies is necessary to avoid misdiagnosis. In the optimal situation, all semen analyses should be screened for sperm-bound antibodies, but if this is impractical, testing should be performed on high-risk individuals (Table I). In couples in which the man has sperm-bound antibodies, and in whom there is no identifiable female factor, treatment should be instituted. Most treatments for immunoinfertility have been disappointing because of poor results, adverse effects, or high cost. Corticosteroid therapy has shown some promise in published reports (mostly poorly designed studies), but increase in pregnancy rate is modest and adverse effects may be significant. In our opinion, informed consent should be documented prior to institution of corticosteroid therapy, and subjects should be closely monitored. Advanced reproductive technologies offer a higher safety profile, and, with increasing technology, higher pregnancy rates. We recommend progressing from "low-tech" procedures, such as IUI and reserving the higher level procedures, such as IVF and ICSI, for those couples in whom pregnancy does not occur. The highest level reproductive technologies give the best current prospects for pregnancy in patients with this difficult problem but also are invasive and costly. It is hoped that further work in the laboratory will give rise to newer, safer, and less expensive effective treatments in the very near future.