HBs antigen in human plasma fractions.

Therapeutic fractions were obtained by fractionating human plasma containing HBs antigen, by the Cohn ethanol technique modified by Nitschmann. Plasmas with various HBs antigen titers were selected. The antigen was sought in each fraction by the techniques of counterelectrophoresis and radioimmunological detection in liquid phase. With the exception of very pure albumins, all fractions were found to contain the HBs antigen, though in variable proportions. A technique for the purification of albumin, applicable on an industrial scale, is proposed. It makes it possible to obtain an albumin fraction in which the HBs antigen cannot be detected by the most sensitive techniques, even starting with a plasma which is very rich in HBs antigen (titer 1/64 by counterelectrophoresis).