Masaya Takikawa

β-Microseminoprotein/prostatic secretory protein is a member of immunoglobulin binding factor family

Human seminal plasma contains a factor that binds human IgG, designated as immunoglobulin binding factor (IgBF). Under reducing condition IgBF interacts with anti-Leu-11b, a murine monoclonal antibody raised against human FcgammaRIII/CD16. IgBF shows no binding activity under non-reducing condition. Three components having IgBF activity were separated by HPLC and their amino acid sequences determined. The main IgBF showed structural identity to beta-microseminoprotein (beta-MSP), prostatic secretory protein of 94 amino acids (PSP94) and beta-inhibin. The slight variation in the reported sequences of these proteins has been attributed to analytical error. In the present study the molecular masses of main IgBF and beta-MSP/PSP94 were found to be identical by mass spectrometry. In addition, a large component of IgBF and a shorter beta-MSP consisting of 93 amino acids were identified. The binding of beta-MSP for human IgG and anti-Leu-11b antibody is demonstrable only under reducing condition, determined by Western blot analysis. The present data clearly show that IgBF is a family composed of at least three isoforms. One of the members is beta-MSP/PSP94. This family should be designated as IgBF.

Complement-Inhibiting Activity of Human Seminal Plasma and Semen Quality

Human seminal plasma (SP) contains potent complement inhibitors. This study examined the complement-inhibiting activity of individual SP samples from 118 patients with infertility and analyzed them in relation to various semen parameters. When 25% complement-inhibiting activity was considered the cut off value, less than 1 SD unit from the mean percentage of inhibition of SP samples with normal semen quality, 32 samples (27%) showed low inhibiting activity. Among the lower group, incidences of patients with asthenozoospermia (66%) and oligozoospermia (31%) were significantly (p < .01) higher than those (36 and 10%) in the group whose SP showed significant inhibiting activity. Partial characterization revealed that the component responsible for complement inhibition was heat labile, trypsin resistant, high molecular weight (>10 kD) glycoprotein that can inhibit alternative as well as classical complement pathways. Furthermore, since in the majority of SP samples the anticomplementary activity was blocked by monoclonal antibody against membrane cofactor protein (MCP) or decay accelerating factor (DAF), the complement-inhibiting factors that were identified are likely to be MCP and/or DAF, which are known to be present in human SP. These results suggest that complement-regulatory proteins in SP such as MCP and DAF may protect sperm cells against complement attack in the male reproductive tract.

Serum Estradiol Concentration as Measured by HPLC-RIA and Bone Mineral Density in Postmenopausal Women during Hormone Replacement Therapy

Objective: To determine the relationship between the serum estradiol concentration and bone mineral density (BMD) of the lumbar spine in postmenopausal women treated with conjugated equine estrogen (CEE) and medroxyprogesterone acetate (MPA) every other day and every day. Methods: Eighty-four postmenopausal women were randomly treated with hormone replacement therapy (HRT) every other day and every day. Forty-seven women received oral administration of 0.625 mg CEE and 2.5 mg MPA every other day, and 37 women received oral administration of 0.625 mg CEE and 2.5 mg MPA every day. BMD of the lumbar spine at 12 months and serum concentrations of estradiol and estrone at 6 and 12 months after treatment were examined. Results: The estradiol concentration in subjects treated every other day showed a significant (p < 0.001) positive correlation with the percentage change in lumbar BMD, while that in subjects treated every day was not correlated with the percentage change in BMD. The differences between serum estradiol concentrations after 12 months of treatment and initial serum estradiol values in women treated every other day and every day also showed a significant (p < 0.01 and 0.05, respectively) positive correlation with percentage changes in BMD. In women treated every other day, body mass index (BMI) in the subjects in whom BMD did not increase was significantly (p < 0.01) lower than that in the subjects in whom BMD did increase. Conclusions: The serum estradiol concentration in women treated every other day has a strong positive correlation with the percentage change in lumbar BMD, but a higher estradiol concentration may be needed for women in whom BMD did not increase with HRT every other day after due consideration of individual characteristics such as BMI.

Identification of the human sperm protein that interacts with sperm-immobilizing antibodies in the sera of infertile women

OBJECTIVE To identify the target antigen of sperm-immobilizing antibodies present in the circulation of infertile women. DESIGN Laboratory research. SETTING Academic research laboratory. PATIENT(S) Twenty-nine infertile women with sperm-immobilizing antibodies, 22 infertile women with other disorders, and 20 fertile women. INTERVENTION(S) Titers of antibodies to the sperm protein, rSMP-B, were determined by ELISA using as substrate the synthetic peptide segment (rSMP-230) that corresponds with the hydrophilic domain of rSMP-B. Tests for sperm immobilization and zona pellucida penetration were performed using the human IVF system. MAIN OUTCOME MEASURE(S) Human sera with sperm-immobilizing activity were assayed for the presence of antibodies to rSMP-230. Polyclonal antibodies to rSMP-230 were assessed for the same biologic activities as sperm-immobilizing antibodies. RESULT(S) Antibodies to rSMP-230 were detected in 10 (34%) of 29 sera obtained from women with immunologic infertility. In contrast, only one serum sample (2%) from women without sperm-immobilizing activity had a low titer of antibodies to rSMP-230. Polyclonal antibodies to rSMP-230 completely immobilized human sperm in the presence of complement and blocked sperm penetration across the zona pellucida. CONCLUSION(S) The human sperm protein, rSMP-B, probably is the target antigen of sperm-immobilizing antibodies.

Effects of postmenopausal hormone therapy every day and every other day on lipid levels according to difference in body mass index

Objective: The objective of this study was to determine the effects of postmenopausal estrogen and progestogen therapy (EPT) every day and every other day on lipid levels, particularly triglyceride (TG) levels, according to difference in body mass index (BMI). Design: Ninety-nine postmenopausal women (mean age, 53.9 ± 5.6 years; mean BMI, 22.8 ± 2.8 kg/m2) were randomly treated with EPT every other day or every day for 1 year. Fifty women received oral administration of 0.625 mg of conjugated equine estrogen (CEE) and 2.5 mg of medroxyprogesterone acetate (MPA) every other day, and 49 women received oral administration of 0.625 mg of CEE and 2.5 mg of MPA every day. Blood samples were collected at baseline and after 1 year of therapy for measurement of fasting TG, total cholesterol, high-density lipoprotein-cholesterol (HDL-C), and apolipoproteins. Data from 88 of the 99 postmenopausal women were used for analysis. Results: In women whose BMI was 25 kg/m2 or higher, TG levels during EPT every day increased by 26.8%, while TG levels during EPT every other day decreased by 12.3%. There was a significant (P < 0.05) difference between percentage changes in TG during EPT every day and every other day. In women whose BMI was less than 25 kg/m2, TG levels during EPT every day increased by 21.7%, while during EPT every other day TG levels did not change. The mean levels of estradiol during EPT every day in women whose BMI was less than 25 kg/m2 and in women whose BMI was 25 kg/m2 or higher were 28.5 and 38.7 pg/mL, respectively, the difference between these levels was significant (P < 0.01). On the other hand, there was no significant difference between levels of estradiol during EPT every other day in these two BMI groups. Conclusions: Triglyceride levels during EPT every day with conventional doses of CEE and MPA increased more in overweight and obese postmenopausal women in association with increased estrogen levels.

Evaluation of two sperm antigens, rSMP-B and YWK-II, as targets for immunocontraception.

To determine whether sperm membrane components, rSMP-B and YWK-II, are suitable candidates as immunocontraceptives in humans, antifertility activities of the antibodies to the peptide fragments, rSMP-229 and rSMP-230 of rSMP-B and YAL-198 of YWK-II, were examined. In a previous report, anti-rSMP-230 antibody was shown to immobilise human sperm and to block human fertilisation, and the antigen (rSMP-230) to interact with antisperm antibodies found in sera of infertile women. Antibody to the second synthetic peptide, rSMP-229, corresponding to a different segment of rSMP-B, mimicked the biological activities of the anti-rSMP-230 antibody. Anti-YAL-198 antibody significantly, although weakly, inhibited human fertilisation. In the murine model, the anti-rSMP-B antibodies blocked in vitro fertilisation of mouse eggs but had no influence on embryo growth. Anti-YAL-198 antibody, however, arrested the growth of zygotes. In conclusion, rSMP-B, a human sperm protein, is a promising candidate in the development of an immunocontraceptive for human application. A second sperm protein, YWK-II, is effective as an antifertility immunogen in experimental animals.

Specific cytotoxicity of antibody to YAL-198, a sperm antigen peptide, to murine zygote

Active immunization with the peptide segments rSMP-230 and YAL-198, corresponding to the hydrophilic extracellular domain of two human sperm antigens (rSMP-B and YWK-II, respectively), reduced fertility in female rats by different mechanisms. The anti-rSMP-230 antibody interferes with human and murine fertilization, and the anti-YAL-198 antibody blocks the development of mouse embryos. The authors examined in vitro at which stage the antibodies to rSMP-230 and YAL-198 were cytotoxic to murine embryos up to morula/blastocyst stage. Anti-rSMP-230 antibody was not cytotoxic to any stages. On the other hand, the anti-YAL-198 antibody arrested the growth of embryos at the 2-cell stage but not at more advanced developmental stages. When the anti-YAL-198 antibody was used, spotty staining was observed only on the surfaces of embryos that had arrested at the 2-cell stage. Unstained embryos, however, continued to develop normally. In contrast, the anti-rSMP-230 antibody stained murine sperm but failed to stain murine ova and embryos. The present results suggest that the human sperm components rSMP-B and YWK-II play important roles in sperm-egg interaction and early development of the embryo, respectively.