Isolation of a Miniature Swine Seminal Plasma Haemagglutinin From the Sperm Surface

Abstract

To investigate seminal plasma factors which damage the surface of the sperm head during freezing treatment, proteins were recovered from the surface of ejaculated spermatozoa of miniature swine. Semen of miniature swine was washed with phosphate buffered saline and treated with hypertonic saline solutions. The fraction showed significant haemagglutination activity. Proteins in the fraction were separated by SDS-PAGE. Five major proteins were purified by excision from the gels followed by electro-elution, and then antisera against the proteins were produced using mice. Haemagglutination inhibitory assay demonstrated that only anti-13K serum inhibited haemagglutination of the fraction. Immunocytochemistry clearly showed that anti-13K serum reacted to the whole surface of ejaculated sperm. Furthermore the antiserum showed a slightly stronger reaction to the swollen surface of one-hour frozen spermatozoa than untreated spermatozoa. The materials seen in the frozen sperm specimen, considered as aggregates of the released sperm surface complex, also reacted with the anti-13K serum intensively. In addition, the 13K-protein was constantly detected in seminal plasma precipitates during the entire freezing treatment. The present data indicated that one of the sperm surface proteins isolated with a hypertonic saline solution is a haemagglutinin, which might be involved in the aggregation of seminal plasma during freezing.