Inhibition of the Hirst Haemagglutination Reaction by Pneumococcal Extract,Normal Serums,and Blood Cell Esterases. ∗

Abstract

Summary

1. Filtrates and autolgsates of Type I and Type V pneumococcus cultures inhibited the agglutination of chicken red cells by influenza virus. 2. Chicken red cells treated with such a filtrate (or autolysate) could not then be agglutinated by the virus. 3. Human red-cell extracts and normal sera of man, guinea pigs, and rabbits were also shown to be capable of inhibiting agglutination of chicken red cells by influenza virus, although some differences of behavior were noted. 4. The presence of a cholinesterase in each of these agents was shown and their possible significance in agglutinin inhibition was discussed