Immunological consequences of vasectomy and vasovasostomy in rhesus monkeys.

The effects of circulating antibodies on fertility after vasovasostomy was studied in rhesus monkeys. After vasectomy there was rapid rise in antibody levels against spermatozoa; these reached a peak after 2 weeks, rather more rapidly than has been reported in man. Antibody levels declined after this period. Monkeys with high antibodies were also more likely to have granulomas and fistulas. After vasovasostomy several monkeys became fertile again with sperm counts in ejaculate reaching a high level at 3 months, although levels were lower than before vasectomy. Some males retained a high and sustained level of sperm immobilizing antibodies in plasma, sometimes for 18 months or more. These males produced fewer spermatozoa and were more likely to be subfertile or infertile after vasectomy. Almost all the monkeys without antibodies were fertile. Presence of antibodies at vasovasostomy was not a definite indication of subsequent infertility but did provide an indication of likelihood of continuing sterility. These are similar to observations of men undergoing vasectomy and vasosostomy.