Young male Japanese quail were given serial injections of homologous testicular antigen by various routes, some with adjuvant and some without. Control birds were injected with isotonic saline or saline plus adjuvant. When the birds reached the age of sexual maturity, data were obtained on serum antibody titres, semen characteristics, testis weight and histology, and fertility of tester females.
The only two treatments which definitely induced immunity were those in which Freund's adjuvant was mixed with the antigen before injection (intraperitoneal or intramuscular). These two treatments resulted in detectable serum antibody titres against quail testis homogenate and also altered the testicular histology to a varying degree. The only tester females with significantly subnormal fertility were those inseminated with semen from the males injected intraperitoneally with antigen plus adjuvant. This semen was characterized by the lowest sperm density of any group and a high methylene-blue-reduction-time.
The observation that spermatozoal agglutination (head-to-head) occurred in the vasa deferentia of some males with serum anti-testis titres suggests that circulating sperm antibodies can enter the male reproductive tract.
As a result of this study, the male Coturnix can be added to the short list of animals in which active immunity and suppression of spermatogenesis have been induced by homologous testicular (spermatozoal) antigen.