Neutralization of Pasteurella haemolytica leucotoxin by bovine immunoglobulins.

Abstract Purified bovine immunoglobulin (Ig) G2 neutralized Pasteurella haemolytica Al leucotoxin in vitro more efficiently than IgG1; IgM did not neutralize. A significant correlation was found between the neutralization titre of unfractionated immune serum and the specific binding of IgG2 only, when measured in an antiglobulin ELISA using P. haemolytica culture filtrate as the coating antigen.