Antigenic variability among North American and European strains of porcine reproductive and respiratory syndrome virus as defined by monoclonal antibodies to the matrix protein

Abstract

Two hybridoma cell lines producing monoclonal antibodies (MAbs) to the 19-kDa matrix (M) protein of porcine reproductive and respiratory syndrome virus (PRRSV) were obtained from BALB/c mice that were immunized with a reference Quebec tissue culture-adapted strain (strain IAF-Klop). The polypeptide specificities of the MAbs were determined by immunoblotting and immunoprecipitation tests with concentrated and purified preparations of the virus and by determining their reactivities with the Escherichia coli-expressed gene products of open reading frames 5 to 7. The two anti-M protein MAbs (MAbs IAFK3 and IAFK6) and another MAb (MAb IAFK8) directed to the 15-kDa nucleocapsid (N) protein were devoid of virus-neutralizing activity. A library of four anti-N protein MAbs (MAbs IAFK8, SDOW17, VO17, and EP147) and two anti-M protein MAbs (MAbs IAFK6 and IAFK3) was used to investigate, by an indirect fluorescent-antibody assay, the antigenic diversity of 15 Canadian PRRSV isolates, in comparison with those of the U.S. ATCC VR2332 attenuated vaccine strain and two reference European (Lelystad and Weybridge) PRRSV strains. The North American and European PRRSV isolates tested shared the epitopes recognized by anti-N protein MAbs IAFK8 and SDOW17, but three distinct patterns could be identified on the basis of their reactivities with the other anti-PRRSV MAbs. No reactivity to the anti-M protein MAbs was observed by either European PRRSV isolate or the attenuated U.S. vaccine strain. MATERIALS AND METHODS Reference virus strains and antibodies. The Quebec cytopathic strain IAF-Klop of PRRSV (14) was used as the reference strain. The virus was propagated in MARC-145 cells (11, 16), a cell line highly permissive to PRRSV, kindly provided to us by J. Kwang,

Field Evaluation of a Live Vaccine against Porcine Reproductive and Respiratory Syndrome in Fattening Pigs

“…However, when, in 1996, this vaccine was imported into Europe and used in Danish farms, several problems appeared as the vaccine virus was transmitted in naive sow populations and caused reproductive disease similar or even more severe than that caused by the virulent virus (Botner et al, 1997;Plomgaard, 1997). It is possible that due to antigenic differences that exist between American and European isolates (Wensvoort et al, 1992;Murakami et al, 1994;Magar et al, 1995;Dea et al, 1996), not only may vaccine-induced immunity be of limited use in controlling the spread of field strains, but immunity to the field strains may have been of limited use in controlling the spread of the vaccine strain. Moreover, the effectiveness of this American live vaccine under field conditions has recently been tested by Sornsen et al (1998) in herds in North America were the syndrome was endemic.…”

Analysis of viral proteins of porcine reproductive and respiratory syndrome virus in host protection and early virus-cell interactions

“…Antigenic diversity has been shown among PRRSV field isolates using monoclonal antibodies to PRRSV and nucleic acid analysis Kapur et al, 1996& Wieczorek-Krohmer et al, 1996. Draw et al (1995), and Pirzadeh et al (1997) did not find common recognition sites, but , Wieczorek-Krohmer et al (1996), Dea et al (1996) and Rodriguez et al (1997) reported common antigenic sites between the two genotypes. We found that most of the MAbs described in this report did not react with European prototype PRRSV strain LV by immunofluorescence assay and that two of the MAbs (PP4cB11 and PP5eA12) had a very weak reaction with LV (data not shown), hence they were not examined further by fixed-cell ELISA.…”

Development of molecular techniques for the detection and pathogenesis study of swine corona-and corona-like virus

“…American and European isolates (Dea et al, 1996;Drew etal., 1995;Nelson et al, 1993;Wieczoreck-Khromer et al, 1996). The European isolates are antigenically similar to each other, but differ from the U.S. isolates.…”