Complex nature of the human antisperm antibody response in SCID mice

Human peripheral blood mononuclear (PBMs) cells were introduced into the peritoneal cavity of severely‐combined immunodeficient (SCID) mice in concentrations of 2.5–4.0 × 10⁷ cells per mouse. Whole mononuclear cell suspensions were used either unstimulated or following primary in vitro culture with human spermatozoa. In some experiments, immunodepletion of CD8⁺ cells was carried out prior to grafting. Lymphocytes were obtained from nonsensitized (to antigen) human subjects or from individuals who were primed in vivo (vasectomized individuals in case of sperm antigens). An enzyme‐linked immunosorbent assay was employed to assess total human immunoglobulin (G or M) levels as well as the specificity of the antibodies generated. We have been successful by generating primary and secondary immune responses with ‘naïve’ human lymphocytes, challenged with chlamydia or ovalbumin but without adjuvant or CD8⁺ immunodepletion; however, we were unable to induce specific antibodies to spermatozoa under this regime in SCID male mice. We then employed female SCID mice, treated with sperm antigen extracts (glycosylated or deglycosylated) encapsulated in liposomes and human lymphocytes obtained from ‘naïve’ or pre‐sensitized in vivo subjects. It was found that the most pronounced humoral response to sperm antigens was obtained with deglycosylated antigens and PBMs from vasectomized (in vivo pre‐primed to spermatozoa) individuals. A presented SCID mice model can be helpful at understanding of antisperm antibody development and the molecular nature of generated antibodies to modified sperm antigenic entities.