Equine influenza: evaluation of the humoral immune response through the hemagglutination inhibition and single radial haemolysis, in vaccinated horses with commercial and experimental vaccines

Abstract

Equine Influenza: evaluation of the humoral immune response through the hemagglutination inhibition and single radial haemolysis, in horses vaccinated with commercial and experimental vaccines. From 4 equine groups, the antibody protection levels against influenza were evaluted through the hemagglutination inhibition and single radial haemolysis. One group of these animals received immunization from 2 doses of influenza vaccine, of experimental preparation, at the Butantan Institute, São Paulo, Brasil (IB). Two other horse groups, regularly vaccinated received the annual booster dose from both commercial and experimental vaccines (IB). A control group remained without vaccination. Differences were observed among the antibody level medians of the serum samples harvested prior and post immunization of those vaccinated animals. No evident differences were detected among the antibody level medians from animals that received annual booster doses, due to the persistence of the protective antibody level, 12 months after the regular immunization. In the control group, the animals showed low antibody levels, for both serum samples. In fact these results suggested the good serologic response of both vaccines, the commercial and the experimental, tested preparations.