• Molecular weight heterodispersion;
  • antigens;
  • trichloroacetic soluble fraction;
  • human seminal plasma

ABSTRACT: The antigens isolated from the trichloroacetic acid soluble fraction of human seminal plasma show a polymodal molecular weight heterodispersion. The molecular weights corresponding to the modes of the distribution have limiting values of 2,500-57,000.

Previous results obtained by polyacrylamide gel and cellogel electrophoresis, immunodiffusion and Immunoelectrophoresis, and ultracentrifugation analysis, which suggested homogeneity, were explained by the formation of molecular aggregates, which would also explain why the smaller fragments were not lost during the dialysis carried out in the preparation and purification of the samples.

The average molecular weight of the antigens, determined by gel permeation chromatography and using the equation of Svedberg, is in the range of 10,000–40,000.

It is suggested that the polymodal heterodispersion together with the associating-dissociating properties of these products is used to control their immunological behavior.