Haemophilus somnus complex: antigenicity and specificity of fractions of Haemophilus somnus

Abstract

Five Haemophilus somnus type 8025 preparations (whole cell, sonicate, crude polysaccharide, purified polysaccharide, and protein) were produced for studies of their antigenicity in rabbits. Bacterial agglutination and passive hemagglutination tests were used to assess the level of antibody produced in rabbits inoculated with the different antigenic preparations. Cross-reactions were seen between the antiserums against the H sumnus 8025 antigens and a variety of related and unrelated bovine pathogens. The strongest cross-reaction occurred between antiserums against H somnus 8025 whole cell and crude polysaccharide antigens and Haemophilus agni and Actinobacillus lignieresii cell suspensions.