Studies on purification of antibodies. II.

Abstract

This paper is the continuation of one delivered before this Society1 describing the metal precipitation and purification of typhoid agglutinating extract. The extract is prepared by sensitizing typhoid bacilli with antityphoid horse serum, washing the complex with saline to remove horse serum and subsequently dissociating agglutinin from bacteria by means of weak alkali.In that paper it was stated that a m/200 final concentration of CuCl2 was used to precipitate agglutinin from the extract. We have found that at the proper hydrogen ion concentration, much smaller amounts of copper will precipitate all the agglutinin. The limiting concentration of copper seems to vary with different extracts, and with the same extract at varying hydrogen ion concentrations. For instance, an extract agglutinating in a dilution of 1:640 was precipitated with copper chloride. When 1.0 cc. N/40 HC1 was added to 10 cc. of extract before the addition of copper, the final concentration of M/4400 CuCl2 was sufficient to bring down...