Characterization of HS80 monoclonal antibody for detection of its antigen on the surface of human sperm

Since interaction between sperm and ovum results in fertilization, determination of molecular events and glycoproteins involved in this interaction may clear the cause of infertilitiy due to molecular defects or immunologic reasons. Thus we studied the properties of mentioned antigens in views of antigenic site and determination of its molecular weight and cross reactivity with other antigens by antisperm monoclonal antibody (HS80). Surface sperm antigens were extracted by NaCl and Lithium diiodosalicylate (LIS) separately. At the next stage, the location of mentioned antigen was determined by indirect immunofluorescence using HS80 monoclonal antibody. Meanwhile, molecular weight of mentioned antigen was measured by immunoblotting. Finally, ELISA was used to study the cross reactivity of monoclonal antibody with human peripheral blood leukocytes, semen proteins and other mammalian sperms (from rat and mouse). Sub-equatorial and collar regions of all sperms had shiny fluorescence after immunofluorescence staining. Likewise, molecular weight range of the antigen was 80±4. Meanwhile, there was not any cross-reactivity among the antibody and other antigens except a 80 kD human leukocyte surface antigen. The presence of the antigen with 80 kD on sub-equatorial region may increase the possibility of its role in vital processes of sperm such as sperm/oocyte membrane fusion and fertilization. Thus,it is recommended to study the role of this antigen in fertilization, in the presence and absence of HS80 monoclonal antibody, sperm interaction with zona pellucida and Oolema using sperm functional studies.