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Kinetics of the porcine reproductive and respiratory syndrome virus (PRRSV) humoral immune response in swine serum and oral fluids collected from individual boars

Apisit Kittawornrat1, Mark Engle3, Yaowalak Panyasing1, Chris Olsen1, Kent Schwartz1, Anna Rice4, Sergio Lizano4, Chong Wang12 and Jeffrey Zimmerman1*

Author Affiliations

1 Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, 50011, USA

2 Department of Statistics, College of Liberal Arts and Sciences, Iowa State University, Ames, IA, 50011, USA

3 PIC North America, 100 Bluegrass Commons Blvd, Hendersonville, TN, 37075, USA

4 IDEXX Laboratories, Inc, Westbrook, ME, 04092, USA

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BMC Veterinary Research 2013, 9:61  doi:10.1186/1746-6148-9-61

Published: 28 March 2013



The object of this study was to describe and contrast the kinetics of the humoral response in serum and oral fluid specimens during acute porcine reproductive and respiratory syndrome virus (PRRSV) infection. The study involved three trials of 24 boars each. Boars were intramuscularly inoculated with a commercial modified live virus (MLV) vaccine (Trial 1), a Type 1 PRRSV field isolated (Trial 2), or a Type 2 PRRSV field isolate (Trial 3). Oral fluid samples were collected from individual boars on day post inoculation (DPI) -7 and 0 to 21. Serum samples were collected from all boars on DPI −7, 0, 7, 14, 21 and from 4 randomly selected boars on DPI 3, 5, 10, and 17. Thereafter, serum and oral fluid were assayed for PRRSV antibody using antibody isotype-specific ELISAs (IgM, IgA, IgG) adapted to serum or oral fluid.


Statistically significant differences in viral replication and antibody responses were observed among the three trials in both serum and oral fluid specimens. PRRSV serum IgM, IgA, and IgG were first detected in samples collected on DPI 7, 10, and 10, respectively. Oral fluid IgM, IgA, and IgG were detected in samples collected between DPI 3 to 10, 7 to 10, and 8 to 14, respectively.


This study enhanced our knowledge of the PRRSV humoral immune response and provided a broader foundation for the development and application of oral fluid antibody-based diagnostics.

PRRSV; Oral fluid; ELISA; IgM; IgA; IgG; Antibody kinetics