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T Samuel

Publications and source records attributed to T Samuel.

29 records · Page 2Linked to original sources
PubMed1978

Studies on the immunogenicity of protamines in humans and experimental animals by means of a micro-complement fixation test.

A complement fixation study with human, monkey and rabbit sera, using purified sperm nuclear basic proteins as antigens, led to the following conclusions. (1) Protamines, the sperm-specific basic nuclear proteins, may be immunogenic in mammalians. (2) Antibodies detected in the indirect immunofluorescence test on human swollen sperm heads in sera from infertile and vasectomized men, are directed primarily against human protamines. (3) The results obtained suggested that differences in the immunization site and/or in the configuration of the immunizing protamine, may lead to the formation of antibodies directed against different antigenic determinants. Autoimmunity to protamines, following vasectomy or in infertile men, is accompanied by the formation of antibodies cross-reacting with common antigenic determinants present in protamines of other species. Induction of immunity to protamines by means of immunization with protamines-RNA complexes (in rabbits), or protamine-insulin complexes (in humans), leads to the formation of antibodies reacting more specifically with the immunizing protamine, showing only slight cross-reaction with other protamines. (4) The histone-like fraction present in mature human spermatozoa is composed mainly of histone fraction H2B.

Animals↗
PubMed1978

Post-vasectomy autoimmunity to protamines in relation to the formation of granulomas and sperm agglutinating antibodies.

The development of antibodies reacting with nuclear antigens was studied in sera from vasectomized men and monkeys (obtained at intervals of up to 2 and 4 years, respectively, after the operation), by means of a comparative fluorescence study on swollen nuclei of somatic cells, human and salmon spermatozoa. About 30% of forty-seven vasectomized men developed antibodies to protamines. Also four out of fifteen monkeys, vasectomized with or without ligation, developed antibodies reacting with protamines. In general, when antibodies to the homologous protamines reached higher levels, cross-reactions with salmon protamine could be demonstrated as well. No significant reactions could be detected with somatic nuclear antigens in the sera. Comparison between the results obtained with the immunofluorescence test, the agglutination tests and the clinical findings confirmed the association between the development of immune responses to various sperm-antigens and revealed a coherence of anti-protamine activity and granuloma formation at the site of the operation.

Animals↗
PubMed1978

Differentiation between antibodies to protamines and somatic nuclear antigens by means of a comparative fluorescence study on swollen nuclei of spermatozoa and somatic cells.

The indirect immunofluorescence test on swollen nuclei of rat thymocytes, chicken red blood cells and human and salmon spermatozoa was found to be an easy and satisfactory method for the discrimination between antibodies to sperm-specific nuclear antigens and somatic nuclear antigens. This study shows that 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 that they may cross-react with salmon protamine. These sera do not react with somatic nuclear antigens. This comparative fluorescence study and a complement fixation study, performed with sera from diabetic patients, proved that the administration of insulin retard (protamine-zinc-insulin) may lead to the formation of antibodies to the fish protamine. These antibodies may reveal a weak cross reaction with human protamines. The results obtained in this study also prove that the nuclei of chicken red blood cells and human sperm do not contain, or contain very small amounts of, histone fraction H1, and that salmon sperm nuclei do not contain any of the histone fractions, and suggest that the nuclei of mature human spermatozoa contain smaller amounts of histones in comparison to somatic cell nuclei.

Animals↗
PubMed1977

Reproducibility of the indirect immunofluorescence test on swollen human spermheads.

Sera of 111 vasectomized men and infertile men and women were tested in each of two laboratories with the indirect immunofluorescence test on swollen human spermatozoa to detect antibodies against nuclear antigens specific to sperm. Comparison of the results revealed complete agreement in 110 of the sera. There were seventeen concordant positive sera (eight out of eighteen sera from vasectomized men, eight out of seventeen sera from infertile men, and one out of seventy-six infertile women). Most of the antibodies were of the IgG class.

Antibodies↗
PubMed1977

Antibodies reacting with salmon and human protamines in sera from infertile men and from vasectomized men and monkeys.

A micro-complement fixation test was modified for the detection of low-titred antibodies to protamines. Specific immunological reactions with salmon protamine were found with some sera obtained from infertile men and vasectomized men and monkeys. The possibilities that allergic reactions, observed in patients receiving salmon protamine, result from immunity to the fish protamine and from immunological cross-reaction between human and salmon protamines (in cases where auto-immunity to human protamine has developed prior to the administration of fish protamine) are discussed.

Animals↗
PubMed1976

Cross-reaction of antibodies present in sera of vasectomized mice with human swollen spermheads.

Vasectomy induced anti-sperm antibodies in mice were seen to cross react with human spermatozoa. Similarly anti-sperm antibodies in an infertile human male subject were found not only to react with human but also with bovine, porcine and murine sperm. Both observations made with preparations of swollen spermatozoa demonstrate the cross-reactivity of anit-sperm protamine activity of different species. Therefore in spite of known species dependent differences in amino acid composition and sequence of protamines, they appear to have common antigenic determinants.

Animals↗
PubMed1975

Isolation, chemical and immunological characterization of two strongly basic nuclear proteins from human spermatozoa.

Human spermatozoa were solubilized by treatment with urea/guanidine and fractionated by ion-exchange chromatography with Bio-Rex 70 resin. Four fractions were obtained. The acidic proteins pass unretarded, whereas the moderately basic and two strongly basic protein fractions are eluted by means of guanidine gradients. The main protein components of the strongly basic protein fractions have been isolated by gel filtration on Sephadex G-50. The purified proteins have been named human sperm protamine 1 and 2. They contain 47 and 51 aminoacid residues (mol. wt 6280 and 6840), of which 22 and 24 are arginine and 5 and 4 are half cystine residues, respectively. The electrophoretic mobility in urea/polyacrylamide gels is between that of calf thymus histone and salmon protamine. Human protamine 1 and 2 are both auto-antigens as has been detected by a quantitative immunofluorescence inhibition test.

Amino Acids↗
PubMed1975

Autoimmunity to sperm antigens in vasectomized men.

Sera from vasectomized men were tested for the presence of antibodies directed against sperm antigens. A high percentage (about 55%) of the vasectomized men developed agglutinating antibodies. A lower percentage (22%) also developed low titres of antibodies to human protamine, as detected in the indirect IFT on swollen sperm heads and 22% developed cytotoxic antibodies. A correlation was found between the presence of anti-protamine antibodies and the presence of agglutinating and of cytotoxic antibodies. This correlation, and also the fact that they developed after vasectomy, indicates that the formation of antibodies against human protamine is a result of an autoimmune response to spermatozoa. The indirect IFT was also performed on 'normal' unswollen spermatozoa. All the sera were positive at least on one of the sperm antigens located in the acrosome, equator, or post-nuclear region, but no increase nor decrease in titre was found after vasectomy.

Acrosome↗