Variation in immunogenicity of ruminant pestiviruses as determined by the neutralisation assay

Immunogenicity in naı̈ve three-month-old Friesian bull calves of nine ruminant pestiviruses, three each of type 1 bovine virus diarrhoea virus (BVDV), type 2 BVDV and border disease virus (BDV) was directly compared in reciprocal cross-neutralisation tests using sera obtained eight weeks after intranasal and intravenous inoculation with live virus. Cytopathic (CP) type 1 BVDV strain C86, non-cytopathic (NCP) type 2 BVDV strain 890 and NCP BDV strain V2536/2 were found to elicit significantly broad cross-neutralising antibodies against viruses in other species whereas other virus strains in all three species produced a much more pronounced homologous and/or species specific response. Results are clearly relevant in the selection of strains for vaccines against diseases caused by these successful, economically important ubiquitous viruses.