PROBLEM: The purpose of this study was to examine whether the products of activated immune cells influence spontaneous and ionophore-induced sperm acrosome reaction.
METHOD: The spontaneous and ionophore-induced acrosome reaction were evaluated by staining with fluorescein isothiocyanate (FITC) Pisum sativam agglutinin after incubation in capacitating media supplemented with either supernatants from Con-A activated leukocyte cultures or human recombinant (r) IL-Iβ, TNF-α, and INF-γ.
RESULTS: The supernatants from Con A-activated peripheral blood leukocyte cultures at 1:1 and 1:10 dilution significantly increased the rate of spontaneous acrosome reaction (P < 0.001 and P < 0.01). Along with displayed abnormally elevated levels of spontaneous acrosome loss, sperm cells showed an insufficient ability to undergo acrosome reaction in response to the ionophore treatment. Recombinant IL-Iβ at increasing concentrations from 30 to 3 × 104 U/ml did not have an effect on spontaneous and ionophore-induced acrosome reaction. In contrast, spermatozoa that underwent capacitation in media with 7 × 103, 7 × 104, and 7 × 105 U/ml of rINF-γ showed a significant increase in spontaneous and induced acrosome reaction compared to the control (P < 0.001). Recombinant TNF-α at concentrations of 3.5 × 103 U/ml and 3.5 × 104 U/ml significantly inhibited ionophore-induced acrosome reaction (P <0.001). Both rINF-γ and rTNF-α together revealed an effect on the acrosome reaction similar to Con-A generated supernatants (1:1 and 1:10 dilution) only at the highest concentrations.
CONCLUSIONS: Some cases of infertility may result from a defective acrosome reaction (premature acrosome loss or insufficient acrosome response to the stimulants) caused by products of activated lymphocytes and macrophages that are released into the male and female reproductive tracts.