The blocking effects of complement-dependent sperm immobilizing antibodies in the sera of infertile women and monoclonal antisperm antibodies against humans and mice on fertilization were investigated. The hemizona assay (HZA) and sperm penetration assay (SPA) were used to study the inhibitory effects of sera from 22 infertile patients positive for sperm immobilizing antibodies. Use of these tests allowed us to differentiate whether the antibody blocked sperm-zona pellucida tight binding and/or sperm penetration into the ooplasm. The zona pellucida penetration assay (ZPA) was also used to study the effects of four monoclonal antibodies (mAbs) on human sperm penetration into the zona pellucida. Seven mAbs against murine spermatozoa were tested for their inhibitory effects on in-vitro fertilization (IVF) and HZA in mice. Of 22 patient sera with sperm immobilizing antibodies, 21 (95.5%) inhibited HZA attachment and penetration, whereas this did not occur in any of 13 patient sera without these antibodies. However, 19 of 22 (86.4%) patient sera with sperm immobilizing antibodies and eight of 13 (61.5%) patient sera without these antibodies inhibited the SPA. Two (2C6, 1G12) of four mAbs against human spermatozoa showed strong inhibitory effects in all the assays (HZA, ZPA and SPA). One mAb (3B10) did not inhibit HZA but blocked ZPA and SPA. Another mAb (H6-3C4) seemed to have no inhibitory effects on fertilization. Two (Vx 5 and Vx 8) of seven mAbs against murine spermatozoa inhibited IVF in mice but did not block mouse HZA. These findings suggest that antisperm antibodies block fertilization at specific stages. Some of them may inhibit sperm capacitation and thus prevent all processes of fertilization that follow. Some other antibodies may not affect capacitation and sperm binding to zona pellucida but inhibit the acrosome reaction, followed by the blocking of sperm penetration through zona pellucida and ooplasm.

Simian immunodeficiency virus (SIV) can cross the intact vaginal epithelium to establish a systemic infection in macaques (mac). Using this SIVmac model, we found that subcutaneous progesterone implants, which could mimic hormonally based contraceptives, thinned the vaginal epithelium and enhanced SIV vaginal transmission 7.7-fold over that observed in macaques treated with placebo implants and exposed to SIV in the follicular phase of the menstrual cycle. Progesterone treatment also increased the number of SIV DNA-positive cells in the vaginal lamina propria as detected by in situ polymerase chain reaction analysis. Moreover, plasma viral RNA was elevated for the first three months in macaques with progesterone implants, and three of the progesterone-treated macaques developed relatively rapid disease courses. This study shows that SIV genital infection and disease course are enhanced by subcutaneous implants containing progesterone when compared with the rate of vaginal transmission in the follicular phase.

BACKGROUND:Despite the fact that human immunodeficiency virus (HIV) is transmitted by sexual contact, the biology of this mode of transmission remains largely undefined. HIV is present in semen in both cell-free and cell-associated forms and can be isolated from asymptomatic individuals and AIDS patients. The source of HIV in semen and the target cells for HIV transmission to men are unknown. Epidemiologic studies have shown that in men, the presence of an intact foreskin is associated with increased risk of HIV infection.EXPERIMENTAL DESIGN:The reproductive tracts from 13 chronically simian immunodeficiency virus (SIV)-infected adult male rhesus macaques were examined for this study. Routine histologic examination was undertaken to characterize the reproductive tract pathology. In situ hybridization and immunohistochemistry were used to localize SIV-infected cells and determine the immunophenotype of inflammatory infiltrates.RESULTS:SIV-infected cells (macrophages, T cells) were found at all levels of the reproductive tract and were commonly associated with inflammatory lesions. Infected cells were found most consistently in the epididymis. In one animal, SIV-infected cells (presumably Langerhans cells) were present in the stratified squamous epithelium of the foreskin. Testicular atrophy and degeneration were relatively common findings. The most common lesion in the accessory glands was mild lymphocytic inflammation. In addition, atrophy of the glandular elements and interstitial fibrosis in the prostate gland were found. One animal had a granulomatous epididymitis with multinucleate giant cells that may have been a primary SIV lesion.CONCLUSIONS:The reproductive tract pathology in chronically SIV-infected male rhesus macaques and AIDS patients is similar. SIV-infected cells can be found at all levels of the male rhesus macaque reproductive tract and SIV can infect cells in the mucosal epithelium of the foreskin. This latter finding indicates that target cells for HIV transmission may be present in the foreskin epithelium of uncircumcised men.

The simian immunodeficiency virus (SIV)-rhesus macaque model of heterosexual human immunodeficiency virus transmission consists of atraumatic application of cell-free SIVmac onto the intact vaginal mucosa of mature female rhesus macaques. This procedure results in systemic infection, and eventually infected animals develop the clinical signs and pathologic changes of simian AIDS. To achieve 100% transmission with the virus stocks used to date, multiple intravaginal inoculations are required. The current titration study utilized two stocks of SIVmac and demonstrated that a single intravaginal dose of cell-free SIV can reliably produce infection in rhesus macaques. This study also demonstrated that some animals intravaginally inoculated with cell-free SIVmac develop transient viremia characterized by a limited ability to isolate virus from peripheral blood mononuclear cells and lymph node mononuclear cells and no seroconversion to SIV antigen. SIV could be isolated from the peripheral lymph nodes of transiently viremic animals only during periods of viremia and not at times when SIV was not detected in circulating mononuclear cells. Thus, peripheral lymphoid tissues were not reservoirs of infection in the transiently viremic animals. Taken together, these results suggest either that the SIV infection was cleared in the transiently viremic animals or that SIV infection is limited to a compartment of the genital mucosal immune system that cannot be assessed by monitoring SIV infection in peripheral blood mononuclear cells and peripheral lymphoid tissue.

Relevant research efforts in male contraception involve: 1) hormonal approaches to block sperm production by inhibiting the hypothalamic-pituitary-gonadal axis, 2) disruption of sperm production by drugs that act directly on the testes, 3) interruption of sperm transport, and 4) alteration of secretions of the accessory sex glands and their subsequent effect on the spermatozoa. Both agonistic and antagonistic synthetic analogs of the hypothalamic gonadotropin releasing hormone (GnRH) factor cost too much and lack an effective mode of administration. Recent studies indicate that over 90% of Chinese and Indonesian men can develop complete azoospermia following either a testosterone or a progestin and an androgen combination treatment. Vaccines that utilize GnRH and follicle stimulating hormone as the active antigens have been introduced in clinical studies in the US and India. Drugs such as sulfasalazine, pyrimethamine, nitrofurane, and bis(di-chloracytal) diamines reduce male fertility but side effects make them unacceptable. Dinitropyrroles, halopropanedils, chlorosugars, and indazole carboxylic acids have been tried in laboratory animals. Gossypol rendered men infertile in large-scale clinical studies conducted in China but synthesis of safer analogs has not succeeded. Extracts of another plant, tripterigium wilfordii, are used in China as a popular herbal medicine. Vasectomy has improved with no-scalpel vasectomy and by the novel technique of blocking the vas with cured in situ polymeric plugs. Preliminary data suggest that men prefer condoms made from polyurethane as opposed to latex rubber increasingly used to protect against AIDs and sexually transmitted diseases. The antifungal agents, imidazoles, have spermicidal activity and synthetic variants may reduce undesirable side effects. Research on male-oriented methods has intensified during the last 10-15 years, but a new product is not likely to appear in the next 5-10 years.

The ability of two nonoxynol-9 spermicide preparations to prevent the genital transmission of SIV in rhesus macaques was compared. Administration of one mL of contraceptive foam before the intravaginal inoculation of cell-free SIV prevented the genital transmission of SIV to three of six animals, and using one mL of contraceptive gel prevented the genital transmission of SIV to two of six animals. Thus, both contraceptive foams and gels containing nonoxynol-9 provided protection against the genital transmission of SIV.

Despite the fact that human immunodeficiency virus (HIV) is transmitted primarily by sexual contact, the biology of the sexual transmission of HIV is poorly understood Simian immunodeficiency virus (SIV) can be transmitted to female rhesus macaques by placing cell-free virus in to the vaginal canal, and SIV can be isolated from the vaginal secretions of infected rhesus macaques. The authors examined the genital tracts from 16 chronically infected female rhesus macaques and localized SIV-infected cells using in situ hybridization and immunohistochemistry. SIV-infected cells were found in the genital tract of 13 of the 16 animals examined, and in most cases the SIV-infected cells were located in the submucosa of the cervix and vagina However SIV-infected cells were also found in the vaginal epithelium. SIV-infected cells were more common in sites of inflammation than in normal areas. These findings suggest that SIV gains access to genital tract secretions from the cervix and vaginal epithelium.

To understand the biologic processes involved in transmission of HIV, we examined the genital tracts of chronically infected female macaques and localized SIV-infected cells. SIV was found in the genital tract of 12 of 16 animals and SIV-infected cells were located in the cervix and vagina. Inoculation of cell-free SIV into the blind vaginal pouch of hysterectomized macaques resulted in systemic infection. We propose a hypothesis to explain the early events in the genital transmission of SIV.

Researchers collected serum samples from 23 infertile patients with sperm immobilizing antibodies (SI-Ab) and 1 pregnant patient from the Department of Obstetrics and Gynecology at the Hyogo Medical College in Japan to screen sera to determine whether they contained factors to inhibit sperm-zona pellucida tight binding. They used the recently developed hemizona assay (HZA) to test for this binding. The HZA assay showed that all 23 serum samples inhibited sperm-zona pellucida tight binding. The hemizona index (HZI) ranged from 3-53 with a mean of 18.1 (standard deviation of = or - 12) compared to a normal (HZI) of 100. Serum samples with titers 10 of SI50 inhibited sperm-zona binding as well as those with titers -or= 10 of SI50 (HZIs=17.3 vs. 18.9; p.1). All 23 serum samples bound to the surface of sperm plasma membrane after 1 hour coincubation as evidenced by the fact that they all demonstrated 50% IgG beads bound. Further the results of the indirect immunobead test (I-IBT) showed that positive sera (+or= 20% IgG beads) significantly inhibited binding more than negative sera (20% IgG beads bound) (HZIs=12.4 vs. 24.4; p.05). Yet serum with positive I-IBT for IgM did not affect sperm-zona binding (HZIs=17.1 vs. 19.4; p.1). No association existed between HZI and site of IB binding. The researchers interpreted theses results to mean that sera with both SI-Ab and antibodies recognized I-IBT for IgG and IgA may play a significant role to inhibit the sperm-zona pellucida tight binding. In conclusion, physicians should expect patients with low HZI to have more problems conceiving than those with normal HZI. In vitro fertilization using heat inactivated human cord serum or donor serum may help them to conceive.

Characterized WHO monoclonal antibodies (MAbs) to human sperm antigens were evaluated as to whether they inhibited sperm-zona pellucida tight binding as assessed by the hemizona assay (HZA). Of the 26 MAbs tested, only one inhibited zona binding. The whole sperm-specific MAb inhibited zona binding by 70%. The MAb also caused strong agglutination. Two procedures, Sephadex column chromatography and papain digestion, were used to determine whether agglutination or steric hindrance was a factor in the capability of MAb to inhibit zona binding. However, inhibition remained comparable to previous results. The MAb did not prevent capacitation, nor calcium influx and the resulting increase in hyperactivated motility and acrosome reaction. Since its inhibitory influence is not due to agglutination factors, steric hindrance or prevention of normal pre-fertilization maturation, the MAb may be blocking a portion of the zona binding receptor and may be useful in elucidating sperm antigens important to sperm-egg interaction. The approach used in this study allows definition of sperm surface antigens involved in zona pellucida binding.

Two synthetic magainins A and G are shown to have spermicidal activity. Transmission electron microscopic micrographs show that both magainins alter the plasma membranes of sperm and that these actions are rapid. Further studies will better delineate the contraceptive potential of synthetic magainins.

Few systemic approaches for treatment of the infertile male are available. Therefore, the focus has shifted to studies of sperm maturation in the female tract, tests of sperm function, and assisted reproduction. New methods of sperm evaluation allow a better determination of those samples that will and will not fertilize ova. These methods include the strict morphology examination, biochemical approaches such as evaluation of creatine kinase levels, and the hemizona assay. Computer assisted semen analysis has not yet proved important for diagnosis but has provided important research information. For example, the drug pentoxifylline significantly increases velocity and has also been shown to enhance in vitro fertilization. The term subfertile is extensively used in the literature but its clear definition and the prognosis for subfertile men have not been established. Approaches that may increase fertilization rates include reducing the gamete culture volume and removal of cumulus oophorus. Assisted reproductive technologies for patients with ejaculatory dysfunction have also been expanded. The use of improved semen processing techniques, advanced oocyte retrieval, and well-timed intrauterine insemination are enabling physicians to use decreasing numbers of viable sperm to achieve pregnancies.