STUDIES ON MENINGOCOCCAL INFECTION : XIII. CORRELATION BETWEEN ANTIPOLYSACCHARIDE AND THE ANTIBODY WHICH PROTECTS MICE AGAINST INFECTION WITH TYPE I MENINGOCOCCI.

Absorption tests indicated that the protective antibody (Type I) in four antimeningococcal horse sera corresponded closely to one of the components of the polysaccharide preparation previously isolated by the authors from Type I meningococci. This antibody was, however, a minor fraction in the three therapeutic sera tested, being secondary in amount to non-protective antibody corresponding to another component of the polysaccharide preparation, plus antibody corresponding to agar. In one case, removal of the agar-antibody diminished the protective titer by 30 per cent.