[Effect of normal and specific immune sera on neuraminidase activity]

We have got evidence that there is no antigenic relationship reflecting the structural similarity between neuraminidases synthesized by noncholera vibrios and Arthrobacter nicotianae. The cross-reactions between the enzymes and heterological antisera were not observed. Antibodies against the A. nicotianae neuraminidase inhibited the activity of the enzyme for a glycomacropeptide of milk whey and for components of the blood serum, and had no effect no the neuraminidase from noncholera vibrios. Antibodies against the neuraminidase of noncholera vibrios inhibited only the activity of the homologous enzyme. Upon gel-filtration on Sephadex G-200 the antibodies inhibiting the activity of the enzymes under study were found in the fraction of 7S-gamma-globulins.