Reactivity of Porcine Epidemic Diarrhea Virus Structural Proteins to Antibodies against Porcine Enteric Coronaviruses: Diagnostic Implications

Giménez-Lirola, Luis
Zhang, Jianqiang
Carrillo-Avila, Jose Antonio
Chen, Qi
Magtoto, Ronaldo
Poonsuk, Korakrit
Baum, David H.
Piñeyro, Pablo
Zimmerman, Jeffrey
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American Society for Microbiology
Giménez-Lirola, Luis
Associate Professor
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Veterinary Diagnostic and Production Animal Medicine
The development of porcine epidemic diarrhea virus (PEDV) antibody-based assays is important for detecting infected animals, confirming previous virus exposure, and monitoring sow herd immunity. However, the potential cross-reactivity among porcine coronaviruses is a major concern for the development of pathogen-specific assays. In this study, we used serum samples (n = 792) from pigs of precisely known infection status and a multiplex fluorescent microbead-based immunoassay and/or enzyme-linked immunoassay platform to characterize the antibody response to PEDV whole-virus (WV) particles and recombinant polypeptides derived from the four PEDV structural proteins, i.e., spike (S), nucleocapsid (N), membrane (M), and envelope (E). Antibody assay cutoff values were selected to provide 100% diagnostic specificity for each target. The earliest IgG antibody response, mainly directed against S1 polypeptides, was observed at days 7 to 10 postinfection. With the exception of nonreactive protein E, we observed similar antibody ontogenies and patterns of seroconversion for S1, N, M, and WV antigens. Recombinant S1 provided the best diagnostic sensitivity, regardless of the PEDV strain, with no cross-reactivity detected against transmissible gastroenteritis virus (TGEV), porcine respiratory coronavirus (PRCV), or porcine deltacoronavirus (PDCoV) pig antisera. The WV particles showed some cross-reactivity to TGEV Miller and TGEV Purdue antisera, while N protein presented some cross-reactivity to TGEV Miller. The M protein was highly cross-reactive to TGEV and PRCV antisera. Differences in the antibody responses to specific PEDV structural proteins have important implications in the development and performance of antibody assays for the diagnosis of PEDV enteric disease.
This is a manuscript of an article published as Gimenez-Lirola, Luis Gabriel, Jianqiang Zhang, Jose Antonio Carrillo-Avila, Qi Chen, Ronaldo Magtoto, Korakrit Poonsuk, David H. Baum, Pablo Piñeyro, and Jeffrey Zimmerman. "Reactivity of anti-PEDV structural protein antibodies to porcine enteric coronaviruses: diagnostic implications." Journal of Clinical Microbiology (2017). DOI: 10.1128/JCM.02507-16. Copyright 2017 American Society for Microbiology. Posted with permission.