Localization of seminal plasma transforming growth factor-beta(1) on human spermatozoa: An immunocytochemical study

Objective: To localize immunocytochemically transforming growth factor beta(1) (TGF-beta(1)) in human spermatozoa. Design: Incubation of spermatozoa with anti-TGF-beta(1) antiserum at various pH. Setting: Human volunteers in an academic research institute. Patients: Young healthy fertile men. Interventions: Semen specimens were collected. Results: At neutral pH and at physiological pH of seminal plasma, TGF-beta(1) immunostaining was detected predominantly at the postacrosomal region of the head, at the neck, and at the middle piece of the tail. Transforming growth factor-beta(1) also was found occasionally at the axial filament complex of the connecting piece and the ring. The acrosomal cap section of the head, the principal piece, or the end piece of the tail were immunocytochemically negative for TGF-beta(1). The TGF-beta(1) immunostaining pattern at acidic pH was similar to that at neutral pH and at physiological pH of seminal plasma, but a greater intensity of immunostaining was found at acidic pH than that at neutral pH. Conclusion: These results suggest that an in vivo activation of seminal plasma latent TGF-beta(1) may take place in the acidic environment of vagina, which results in a greater amount of activated TGF-beta(1) and, in turn, with an enhanced ''coating'' of TGF-beta(1) to spermatozoa.