Is there a relationship between infertility and fertilin β protein distribution?

Fertilin β is a sperm surface protein that can mediate sperm-egg membrane interaction. This study was conducted to determine whether the expression of fertilin β after intrauterine insemination (IUI) in donors with normal parameters after standard semen analysis is related to low success rate or failure of fertilization.

We examined the sperm of 30 male donors who have normal as controls, oligozoospermia, and unexplained infertility as the clinically indication for IUI. Fertilin β has been labeled with the ADAM2 antibody by indirect immunofluorescence (IF) assay. To evaluate the reproducibility of the test, we selected four sperm samples scale of 0 to +++ according to the distribution of fluorescence label.

The results were highly correlated with the corrected total cell fluorescence (CTCF) (R_p=0.9972, P<0.05). We suggest that the relationship between infertility and fertilin β may be due to the distribution of this protein on the sperm surface. Male partners of couples with unexplained infertility showed a low distribution of fertilin β by a decrease of the fluorescence signal in the IF labeling (scale of +++ by 7.4±10.32%, P<0.0001, ±SD).

Abnormal fertilin β function may be a potential mechanism that could lead to fertilization failure.