Studies of Antimeningococcal Serum

Abstract

Summary The agglutinative, precipitative, and complement-fixing activity with meningococcal antigens and with agar was titrated in the serum of horses and rabbits under immunization with meningococci. Type-specific agglutinating activity appeared earlier than nontype-specific activity in both antimeningococcal horse- and rabbit-sera. Although specific activity developed more rapidly in type-I-III monovalent serum than in type-II serum, cross-agglutination or precipitation of heterologous specific polysaccharide was noted earlier in type-II sera. With both horse and rabbit, precipitation and complement-fixation with meningococcal nucleoprotein in the monovalent sera were similar in time of appearance and in titer and were more marked than in the multivalent sera. The immune rabbit-serum fixed complement with the isolated meningococcal polysaccharides; immune horse-serum did not. The standard stock-strains of types I–III and II produced sera quite as specific and equally as high in titer as the more recently isolated type-I-III or -II strains. The precipitation of agar did not parallel the cross-reactions with the heterologous type in these tests. It was comparable in intensity to that in antipneumococcal sera.