Concentration of Pneumococcus Antibody

Abstract

A method was given in a previous publication by which the protective substance of antipneumococcus serum could be concentrated with a resulting product practically free from chill-producing characteristics. It was also stated in the same publication that the steps outlined for the purification of the water-insoluble precipitate obtained by diluting potent serum with water were applicable to the water-insoluble precipitate obtained by the common salting-out methods, using ammonium sulfate or sodium sulfate. It is the purpose of this paper to outline a method of concentration with anhydrous sodium sulfate as the precipitating agent instead of the commonly used ammonium sulfate. Sodium sulfate, rather than ammonium sulfate, is given at present because, as judged from the troublesome reaction after intravenous administration, a better product has been obtained by its use. From the standpoint of concentration of the protective antibody alone, however, ammonium sulfate has not only been used in many experiments with the same result as with sodium sulfate but also it has the advantage of greater ease in handling. The objection to its use, from our experience, is the chill-producing reaction of the final product following intravenous administration. Attempts have been made to obviate this difficulty but so far they have met with only partial success. In the course of our investigation on the pneumococcus antibody, obtained from the serum of immunized horses, certain facts have been observed concerning the associated protein. Although details will be given in other publications a brief summary of our findings will be reported here. In the first place, in contradistinction to Avery's work,2 the antibody has been found by us to be associated only with a waterinsoluble protein; never with the water-soluble pseudoglobulin. This observation has been confirmed by Banzhaf.3 However, the possibility should not be overlooked that the antibody when isolated may be watersoluble and also that the manipulations in Avery's work may have been such that some of the protective antibody was found with the pseu-