Molecular characterization of glycoprotein genes and phylogenetic analysis of two swine paramyxoviruses isolated from United States

Abstract

Two swine paramyxoviruses (SPMV)-(81-19252 (Texas-81) and 92-7783 (ISU-92)-were isolated from encephalitic pigs in the United States in 1981 and 1992. Antigenic, morphologic, and biological characteristics of these two viruses were essentially similar to members of the family Paramyxoviridae. Antigenic analysis by indirect fluorescent antibody, immunoblot, and one-way cross-neutralization tests placed these viruses along with bovine parainfluenza 3 (BPIV3) viruses. Purified virions were 50-300 nm in size and morphologically indistinguishable from other paramyxoviruses. These two viruses hemagglutinated red blood cells and had neuraminidase activity. The gene junctions of fusion (F) and hemagglutinin (HN) glycoprotein genes of these viruses contained highly conserved transcription start and stop signal sequences and trinucleotide intergenic regions similar to other Paramyxoviridae. The F gene of ISU-92 was longer than Texas-81 due to insertion of a 24-nucleotide "U"-rich 3' untranslated region. Structure-based sequence alignment of glycoproteins of these two SPMVs indicated that they are essentially similar in structure and function to parainfluenzaviruses. The Texas-81 strain was closely related to BPIV3 Shipping Fever (SF) strain at nucleotide and amino acid level, while the ISU-92 strain was more closely related to BPIV3 910N strain. The envelope glycoproteins of ISU-92 had only approximately 92 and approximately 96% identity at nucleotide and amino acid levels with BPIV3-SF strain, respectively. The high sequence identities to BPIV3 indicated cross-species infection in pigs. Phylogenetic analyses based on both F protein and HN protein suggested the classification of these viruses into the subfamily Paramyxovirinae, genus Respirovirus, and genotype A of BPIV3.

Complete Genome Sequence and Pathogenicity of Two Swine Parainfluenzavirus 3 Isolates from Pigs in the United States

“…The phylogenetic reconstructions based on the complete M protein amino acid sequences reveal two distinct genetic groupings formed by bPIV3-910N-like and bPIV3-SF-like viruses. In addition, deduced amino acid sequences of M proteins (this study) and the F and HN proteins (57) indicate that Texas81 and ISU92 belong to two subgenotypes of genotype A and that the Australian bPIV3 strain Q5592 belongs to a separate genotype, genotype B (Fig. 1B).…”

“…We have recently reported the molecular characterization of the envelope glycoprotein genes of these two swine viruses (57). In the putative antigenic sites of the F protein, there were several amino acid differences from hPIV3, including E101N, V/T367I (only in ISU92), S418Q, T492A, and T513V, but the amino acids were conserved in the swine viruses and bPIV3.…”

“…Porcine kidney (PK15) cells, tested for and found to be free of porcine circovirus, were obtained from X. J. Meng, Virginia Polytechnic Institute and State University, and used to propagate these viruses for the first three passages. Vero cells (ATCC CCL-81) were used for all tests in this study as described earlier (57).…”

“…Recently, we reported the antigenic and molecular characterization of glycoprotein genes from two novel swine PIV3 (sPIV3) isolates from the brains of pigs that experienced respiratory and central nervous system disease (57). These two sPIV3 strains were antigenically and genetically very closely related to bovine PIV3 (bPIV3) in the genus Respirovirus (57).…”

“…These two sPIV3 strains were antigenically and genetically very closely related to bovine PIV3 (bPIV3) in the genus Respirovirus (57). However, the pathogenicity of these sPIV3 strains in conventionally reared pigs and the complete genome sequences of these isolates are presently unknown.…”