UBC Theses and Dissertations
Studies of sperm antigens using specific monoclonal antibodies Sun, Ping
This thesis work is focused on studies of sperm antigen: its purification and antifertility effect, its "internal image" by use of anti-idiotypic antibodies, and its capacity to induce antibodies of IgA class. Mouse sperm acrosomal antigens that react with a monoclonal antibody generated against mouse spermatozoa, MS 207, were purified by immunoaffinity chromatography from soluble fraction of mouse testis homogenates. Analyzed by HPLC and SDS gel electrophoresis in the presence of reducing agent, the purified sperm antigens were shown to have a molecular weight of 600 to 700 KDa. It was shown to be glycoproteins with carbohydrate content of 23%. The purified mouse sperm antigen was used to isoimmunize female mice. After successive immunizations, antisera of high titers were raised and were shown to react specifically with mouse and human sperm, but not with any mouse somatic tissues as judged from results of immunofluorescent assay and Ouchterlony's double immunodiffusion. The antisera were shown to crossreact with human sperm at the acrosomal region. By using mouse in vitro fertilization experiments and human sperm penetration assay with zona-free hamster ova, the antisera were shown to exert strong inhibitory effects on fertilization. Another part of this thesis work was directed to generating anti-idiotypic antibody against a monoclonal sperm antibody MS 204. MS 204 was previously shown to react with a conformational epitope of sperm antigens. Anti-MS 204 antiserum was raised in a rabbit. A series of affinity chromatographic columns were applied to purify anti-Fab fragment of MS 204 (AId 204). The obtained Aid 204 possessed weak antigenicity in the mouse. After successive immunizations with Aid 204, the isoimmune sera against AId 204 were shown to crossreact with acrosomal region of mouse sperm, a pattern similar to that of MS 204. A partial inhibitory effect on in vitro fertilization was observed. The results indicate that the "internal image" of the specific sperm antigen reactive with MS 204 exists in AId 204. This could be a new strategy to obtain conformational epitope of a given antigen and may serve as the alternative of contraceptive vaccines.
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