Genomic and antigenic variations of the HE glycoprotein of bovine coronaviruses associated with neonatal calf diarrhea and winter dysentery

Abstract

Summary. In this study, we attempted to define differences in the hemagglutinin-esterase (HE) glycoprotein between 11 bovine coronaviruses (BCV) recent (post-1991) and past (pre-1991) isolates from neonatal calf diarrhoea (NCD) and winter dysentery (WD) syndromes as a basis for strain differentiation related to the clinical source of the isolates. The five WD-associated BCV isolates studied could be distinguished from past NCD-isolates by their hemagglutinating (HA) properties at 4 ° and 37 °C, their receptor-destroying enzyme (RDE) activities with rat erythrocytes and lack of reactivity of these NCD isolates to four HA inhibiting (HAI) monoclonal antibodies (MAbs) directed against the HE glycoprotein of the reference WD-associated BCQ.2590 Quebec strain. Although minor or no differences could be demonstrated by comparing biological properties of the HE of WD-isolates to those of recent NCD-isolates, past NCD isolates lacked reactivity with the WD HAI MAbs, whereas recent NCD isolates displayed two distinct reactivity patterns. Attempts to define sequence differences in the HE genes of the WD and NCD strains revealed high nucleotide (NT) identities with only scattered amino acid differences, seemingly unrelated to the clinical origin of the isolates or HAI MAb reactivities.