DIFFERENTIATION BETWEEN ANTIBODIES TO PROTAMINES AND SOMATIC NUCLEAR ANTIGENS BY MEANS OF A COMPARATIVE FLUORESCENCE STUDY ON SWOLLEN NUCLEI OF SPERMATOZOA AND SOMATIC-CELLS

Abstract

The indirect immunofluorescence test on swollen nuclei of rat thymocytes, chicken red blood cells and human and salmon spermatozoa was an easy and satisfactory method for the discrimination between antibodies to sperm-specific nuclear antigens and somatic nuclear antigens. Nuclear antibodies present in the sera of vasectomized men and in rabbit antisera to human protamines are directed against the human sperm-specific nuclear antigens (protamines) and may cross-react with salmon protamine. These sera do not react with somatic nuclear antigens. Studies with sera from diabetic patients, demonstrated that the administration of insulin retard (protamine-Zn-insulin) may lead to the formation of antibodies to the fish protamine. These antibodies may reveal a weak cross-reaction with human protamines. The nuclei of chicken red blood cells and human sperm do not contain, or contain very small amounts of, histone fraction H1. Salmon sperm nuclei do not contain any of the histone fractions. The nuclei of mature human spermatozoa probably contain smaller amounts of histones in comparison to somatic cell nuclei.