Abstract
It has been questioned whether the human chorionic gonadotropin (HCG) could form the specific precipitate with its antiserum or not. To clarify this point directly, the absorbed rabbit anti-HCG serum which showed only one precipitin band to HCG preparation and no band to human serum or child urine protein, was incubated with partially purified HCG at 37°C for 60 minutes and then refrigerated at 4°C for four days. The resulting precipitate was completely washed until no HCG activity was shown in the supernatant and placed in glycine-HCl buffer (pH2.5, 0.167M), and then passed through a Sephadex G-100. The immunologically and biologically active HCG was dissociated from the specific precipitate and fractionated apart from the rabbit 7Sr-globulin. This result was a direct proof that HCG could produce the precipitating antibody in immunized rabbit.
