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LOCALIZATION OF SP22 ON HUMAN SPERM OF DIFFERING QUALITY
Citation:
Lavers, A. E., G R. Klinefelter, D. W. Hamilton, AND K. P. Roberts. LOCALIZATION OF SP22 ON HUMAN SPERM OF DIFFERING QUALITY. Presented at International Congress of Andrology, Montreal, Canada, June 15-19, 2001.
Description:
LOCALIZATION OF SP22 ON HUMAN SPERM OF DIFFERING QUALITY. AE Lavers*1, GR Klinefelter2, DW Hamilton1, KP Roberts1, 1University of Minnesota, Minneapolis, MN and 2US EPA, Research Triangle Park, NC.
SP22 is a sperm membrane protein that has been implicated in sperm function during fertilization. The level of SP22 on rat sperm has been shown to correlate highly with fertility when conventional semen analysis parameters did not. Additionally, antibodies raised against this protein have been shown to inhibit IVF in rats. In rats and hamsters this protein is localized to the equatorial segment, consistent with a role in sperm-egg interaction, and to the tail of the sperm. In human sperm this protein has been reported to be localized only to the sperm tail. Herein, we sought to determine the localization of SP22 in a series of human sperm samples and to associate localization patterns varied with the quality of the sperm sample. Human sperm were obtained from 26 men of unknown fertility and semen parameters (motility, viability and morphology) were evaluated. Subsequent to this, 15 samples were washed, fixed, and immunostained; 11 samples were subjected to Isolatea treatment prior to fixing for immunostaining. Significant numbers of sperm in all samples (34 to 80%) showed staining in the equatorial segment and/or the proximal portion of the neck. Isolatea treatment resulted in a statistically significant increase (from 56 to 66%) in SP22 equatorial segment and proximal neck staining. A low level of SP22 staining was seen on the tails of almost all sperm. Consistent with the previous studies in rats, there was no apparent correlation between SP22 staining and conventional semen analysis parameters. In summary, the localization of SP22 on human sperm is consistent with the role of this protein in fertilization and fertility indicated in animal studies. Correlation of SP22 to fertility in humans awaits a prospective clinical study in infertile men.