VP1 sequences of German porcine parvovirus isolates define two genetic lineages

Abstract

In order to evaluate the genetic variability of Porcine parvovirus (PPV), the complete capsid protein sequences (VP1/VP2) from seven recent field isolates from Germany, one isolate from the UK and one German vaccine strain were sequenced and analysed, along with two American (NADL-2 and Kresse), three Asian and 22 Brazilian partial PPV sequences retrieved from GenBank. The analysis revealed a high degree of diversity: 1?2-2?6 % at the nucleotide level and 1?2-6?8 % at the amino acid level. Phylogenetic analysis defined two German clusters: one formed by four German isolates and the English, Asian and American sequences; and the second, distinct cluster formed by the other three of the seven German isolates examined. The latter cluster was still observed when the 22 partial sequences (853 nt of the 39 terminus of the VP2 gene) from the Brazilian isolates were included in the analyses, indicating that the VP2 sequence determines the phylogeny.Porcine parvovirus (PPV) is an important cause of reproductive failure in swine, characterized by fetal death, mummification, stillbirths and delayed return to oestrus (Mengeling, 1999). It is classified in the genus Parvovirus, the subfamily Parvovirinae and the family Parvoviridae, and contains a single-stranded (minus-strand) DNA genome of about 5 kb. The large ORF1 and the small ORF3, in the left half of the genome, code for the non-structural proteins NS1, NS2 and NS3. ORF2, in the right half of the genome, encodes the structural proteins VP1, VP2 and VP3. VP1 and VP2 are a result of alternative spliced RNAs giving VP1 a specific N terminus of 150 aa. VP3 is generated by proteolytic cleavage of VP2 (Ranz et al., 1989;Bergeron et al., 1993).Although the three structural proteins form the icosahedral non-enveloped capsid, VP2 can assemble into virus-like particles (VLPs) by itself and the immunogenic activity of the VLPs is indistinguishable from that of inactivated whole-virus vaccines (Martinez et al., 1992). Nine linear Bcell epitopes have been defined within the major capsid protein VP2, but so far only peptides from the N terminus of VP2 are known to induce virus-neutralizing antibodies (Kamstrup et al., 1998).The capsid proteins VP1/VP2 of the carnivore parvoviruses canine parvovirus (CPV) and Feline panleukopenia virus (FPV) determine the host range (Chang et al., 1992;Truyen et al., 1995;Shackelton et al., 2005). For PPV, however, not much is known about host-range determinants. Two amino acid differences (one in VP1/VP2 and one in NS1) extend the host range for PPV in cell culture from porcine to porcine and canine cells (Vasudevacharya et al., 1992). The pathogenicity of the highly virulent PPV Kresse isolate appears to be determined by only three substitutions in the VP1/VP2 protein (Bergeron et al., 1996). The threedimensional structure of empty PPV capsids was determined by X-ray crystallography and was found to be similar to that of the related parvoviruses CPV and FPV. The three differences in amino acid sequence associated with the pathogenic phenotype of K...

Vaccination against porcine parvovirus protects against disease, but does not prevent infection and virus shedding after challenge infection with a heterologous virus strain

“…Between the genotypes, an overall identity of about 95 % at the amino acid level (VP1) is observed. Amino acid residues 381, 596 and 586 are consistently different between the genotypes (Zimmermann et al, 2006); however, it has not yet been shown that these amino acids determine the Cross-protection against a heterologous PPV genotype antigenic differences (Zeeuw et al, 2007). The viruses that are used in the two vaccines examined in this study are both genotype 1 viruses and differ in the VP1 gene by only 2 %.…”

“…Fetuses infected before day 70 of gestation usually die, whereas fetuses infected at a later time point develop antibodies against PPV, eliminate the virus and survive the infection (Nielsen et al, 1991). Zimmermann et al (2006) showed that PPV is more diverse than thought previously and that some recent German field isolates differ genetically from the reference and vaccine strains. By phylogenetic analyses based on VP1 sequences, two genotypes could be defined.…”

“…The Stendal virus is related closely to the IDT (MSV) virus and clusters with the genotype 1 viruses (not shown). The challenge virus PPV-27a (Zimmermann et al, 2006) was propagated in SPEV (porcine kidney) cells, obtained from the Friedrich Loeffler Institute (Insel Riems, Germany).…”

An inactivated whole-virus porcine parvovirus vaccine protects pigs against disease but does not prevent virus shedding even after homologous virus challenge

“…If the fetuses are infected after day 70 of gestation, they usually develop antibodies against PPV and eliminate the virus (Zeeuw et al, 2007;Truyen & Streck, 2012). In recent years, studies have shown that PPV is much more diverse than previously thought (Zimmermann et al 2006;Streck et al, 2011). Several PPV strains of different virulence are known.…”

“…Based on phylogenetic analyses of the VP1/VP2 protein genes, PPV can be defined into at least seven clusters (Zimmermann et al, 2006;Streck et al, 2011Streck et al, , 2013a. Recently, a population dynamic analysis showed that, despite the high evolutionary rate, only a few PPV strains (similar to strain 27a) have been predominant in Europe in recent years (Streck et al, 2013b).…”