Acquisition of viable-like surface properties of sperm cells by adsorption of seminal plasma proteins revealed by centrifugal countercurrent distribution.

By using centrifugal countercurrent distribution in dextran/polyethylene glycol two-phase system, we show that the acquisition of adsorbed seminal plasma proteins by the sperm cell surface modifies the partition behaviour of bull spermatozoa reproducing that of alive cells. Thus, addition of increasing concentrations of proteins from the seminal plasma promoted a saturable enhanced affinity of the cells to the polyethylene glycol-rich phase in which alive cells preferentially partition. On the contrary, treatment with Tween provoked the opposite effect.