Monoclonal antibodies to bull sperm surface antigens

Abstract

Four monoclonal antibodies were generated during the present investigation. Mice were immunized with washed ejaculated bull spermatozoa. Spleen cells from the immunized mice were fused with myeloma cells (SP2/0) and four different hybridoma clones were obtained, producing specific monoclonal antibodies. These antibodies were designated as SP2A5, SP1A2, SP1C4 and SP1C6 respectively. All belonged to the IgG sub-class 1. The specificity of these monoclonal antibodies was tested using both ELISA (enzyme-linked immunosorbent assay) and indirect immunofluorescence staining techniques. Quantitative estimation of antibody-antigen reaction was done by optical density measurements. Ejaculated bull spermatozoa were always reactive for each ELISA procedure. Other test cells including spleen, testicular, ovarian, uterine and pancreatic cells from both bull and rabbit were non-reactive. Bull testicular spermatozoa were also non-reactive. However, seminal fluid (without sperm) was reactive. All four monoclonal antibodies were reactive to the midpiece of the ejaculated bull spermatozoa. In addition, SP2A5 was also reactive to the acrosomal area and SP1A2 was reactive to the acrosomal and the post-acrosomal area. Cytoplasmic droplets of ejaculated spermatozoa from bull and human were also possibly reactive to one antibody (SP1C6). The results clearly suggest the heterogeneous nature of the sperm cell plasma membrane and precise molecular alteration in the plasma membrane components (antigens) as the sperm cells differentiate and mature during their transit through the epididymis. © 1985.