Immunologic implications of vasectomy: II. Serum mediated immunity

Thirty male Lewis rats in groups of ten underwent: standard vasectomy with ligation of the vas deferens; vasectomy without ligation of the vas deferens, permitting intraperitoneal drainage of the open vas deferens; and sham vasectomy. One in vivo and one in vitro assay for serum mediated immunity to syngeneic spermatozoa were performed with each experimental group 90 days after the operative procedure. These tests were: Arthus reaction by footpad swelling response 3 hr following footpad injection of syngeneic spermatozoa; release of radioactivity from ⁵¹chromium labeled spermatozoa following incubation with experimental sera, indicating cytotoxic antibodies to spermatozoa. The presence of serum mediated immunity specific to spermatozoa could be demonstrated only in group 1 rats which underwent conventional abdominal vasectomy with ligation of the vas deferens. This study is the first in vivo demonstration of serum mediated immunity to spermatozoa following vasectomy. In addition, the specificity of the serum mediated response to syngeneic spermatozoa was resolved. Whether the observed Arthus reaction and cytotoxic antibodies are related to earlier observations of sperm agglutinating and immobilizing factors remains to be clarified.