|Lwamba, Humphrey C|
|Njeng, M Kariuki|
Submitted to: Avian Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/9/2002
Publication Date: 7/23/2002
Citation: Lwamba, H.M., Cameron, K.T., Halvorson, D.A., Nagaraja, K.V., Turpin, E.A., Swayne, D.E., Seal, B.S., Njeng, M. 2002. Antigenic Cross-Reactivity Among Avian Pneumoviruses Of Subgroups A, B, And C At The Matrix But Not Nucleocapsid Proteins. Avian Diseases 46(3):725-729, 2002. Interpretive Summary: Avian metapneumoviruses cause a disease referred to as turkey rhinotracheitis and were considered exotic to the United States prior to 1997. However, during that year these virus types caused respiratory disease among commercial turkeys in the central United States and the disease continues to persist among commercial poultry. Several techniques have been utilized to detect antibodies in the serum of commercial turkeys to these virus types. Our laboratories have collaboratively developed recombinant DNA antigens for use in serological detection methods. The recombinant viral matrix protein antigen was able to detect antibodies to all known types of the virus including those from both the United States and Europe. Another recombinant protein of the virus, the nucleocapsid protein, was able to be used to detect antibodies to only a single European virus type and the United States avian metapneumovirus. Consequently, certain viral proteins, such as the matrix protein, can be efficiently utilized to detect exposure of commercial turkeys to all the avian metapneumoviruses. However, other viral proteins, such as the nucleocapsid protein, may not be as cross reactive.
Technical Abstract: Earlier findings from our laboratory based on nucleotide and predicted amino acid sequence identities of 15 APV isolates from the United States (subgroup C) demonstrated that the viruses were phylogenetically separated from subgroup A and B viruses. In the present work, we investigated whether viruses from the three subgroups were cross reactive by testing field sera positive for APV subgroups A, B, and C in an enzyme-linked immunosorbent assay (ELISA) test using recombinant matrix (M) and nucleocapsid (N) proteins generated from a Minnesota APV isolate (APV/MN2A). Sera from turkeys infected with APV subgroup A, B, or C reacted with recombinant M protein derived from APV/MN2A. In contrast, recombinant N protein from APV/MN2A virus was reactive with sera from subtype A and C viruses but not from subtype B virus. The results illustrate that viruses from the three APV subtypes share antigenic homology, and the M protein-based ELISA is adequate for monitoring APV outbreaks, but not for distinguishing between different subtypes.