LECTIN HISTOCHEMISTRY OF NORMAL AND HERPESVIRUS-INFECTED BOVINE NASAL-MUCOSA

Proliferation of Pasteurella haemolytica serotype 1 in the nasal cavity following stress or viral infection is an important event in the pathogenesis of bovine pneumonic pasteurellosis. Enhanced adhesion of P. haemolytica to nasal mucosa could be one factor that predisposes animals to this proliferation. Nasal mucosa from normal and bovine herpesvirus-1 (BHV1)-infected cattle were examined histochemically for their glycoconjugate composition. Twenty lectins were screened, six of which were chosen for subsequent study. Three of these were specific for N-acetylgalactosamine (NAGal) (Dolichos biflorus, Glycine max, and Vicia villosa), and one each was specific for N-acetylgalactosamine/galactose (Griffonia simplicifolia-I), mannose/glucose (Canavalia ensiformis), and N-acetylglucosamine (Triticum vulgaris). For the surface mucosa and submucosal glands, there was greater reactivity in samples from BHV1-infected than from normal cattle for all six lectins. Reactivity was most prominent for the NAGal-specific lectins. Neuraminidase treatment of samples from normal and BHV1-infected cattle tended to result in greater lectin reactivity. Lectin reactivity was generally more intense in focally inflamed areas, but diffuse reactivity was not substantially affected by inflammation. BHV1-induced alteration of nasal mucosal glycoconjugates could enhance adhesion and colonization of P. haemolytica to nasal surfaces and may be one factor responsible for the increased number of P. haemolytica serotype 1 in the nasal cavity following viral infection.