Kinetics of HBs antigen in man

The metabolism of HBs Antigen had been studied in three human volunteers. One had chronic hepatitis and two were "silent carriers". The HBs Antigen had been isolated and purified from the plasma of each of the three subjects and, after iodination, reinjected to the same donor. The parameters of plasma kinetics of 131I HBsAg have been analyzed according to a two compartmental model on the basis of the radioactivity of TCA precipitate (TP) and immunoprecipitate (IP). The fast initial volume of distribution was approximately equal in the three subjects (46.6 ml/kg). The metabolic clearance rate (MCR) of IP was the very same in two subjects but is four times higher in one of the silent carrier. The total renewal time (TRT) was about 3.3 days. Assuming that the HBs Antigen extraction was of the order of 65% the plasma HBs Antigen concentration per liter of plasma would be 12 and 53 mg/liter fot two silent carriers and 61 mg/liter for the patient with chronic hepatitis. The radioactive efflux from the model (calculated as IP.MCR multiplied by HBs Antigen concentration) was identical for the two silent carriers adn 50% higher in the patient with chronic hepatitis. This increase possibly reflects an increased synthesis of HBs Antigen in the patient with chronic hepatitis. The cumulative urinary radioactivity when added to the whole body counting demonstrated that radioactivity was excreted solely in the urine. The ratio of organ counting to precordium counting did not vary significantly with time in all subjects.