Latex agglutination test for measurement of type-specific antibody to Haemophilus paragallinarum in chickens.

A latex agglutination test employing serotype-specific Haemophilus paragallinarum polysaccharides as the antigen has been developed. It can be used to measure the antigen-antibody reaction in chicken sera when spontaneous latex particle agglutinin is removed without loss of detectable antibody by kaolin pretreatment. The test was tried to detect the serological response in immunized chickens with two different serotype strains of H. paragallinarum; it could detect the type-specific antibody, and no crossreaction was observed. This latex-agglutinating antibody may be related mainly to immunoglobulin M in primary antisera in which the latex titer was reduced by 2-mercaptoethanol treatment. The latex agglutination test should be valuable as a routine diagnostic method because it is type-specific, simple, and economic and its sensitized latex suspension is stable for at least four months.