Cloning, expression and immunogenicity of the avian pneumovirus (Colorado isolate) F protein

The F protein of the Colorado isolate of avian pneumovirus (APV), expressed from a DNA plasmid, was recognized by antiserum to both A and B subgroup A PVs. After two intramuscular injections of turkeys with this plasmid, a hom ologous antibody response was detected by enzyme-linked immunosorbent assay . This antibody also recognized subgroup A APV. However, there was no neutr alization of the Colorado isolate or of subgroup A or B viruses. Although n o significant clinical protection was detected following homologous challen ge of poults, an anamnestic serological response was seen, suggesting that a systemic antibody response but no local mucosal immunity was induced.