Veterinary and Biomedical Sciences, Department of

 

Document Type

Article

Date of this Version

7-2017

Citation

Vaccine 35:5 (July 2017), pp. 782–788.

doi: 10.1016/j.vaccine.2016.12.040

Comments

Copyright © 2016 Elsevier Ltd. Used by permission.

Abstract

Because porcine reproductive and respiratory syndrome virus (PRRSV) exhibits extensive genetic variation among field isolates, characterizing the extent of cross reactivity of immune responses, and most importantly cell-mediated immunity (CMI), could help in the development of broadly cross-protective vaccines. We infected 12 PRRSV-naïve pigs with PRRSV strain FL12 and determined the number of interferon (IFN)-γ secreting cells (SC) by ELISpot assay using ten type 2 and one type 1 PRRSV isolates as recall antigens. The number of IFN-γ SC was extremely variable among animals, and with exceptions, late to appear. Cross reactivity of IFN-γ SC among type 2 isolates was broad, and we found no evidence of an association between increased genetic distance among isolates and the intensity of the CMI response. Comparable to IFN-γ SC, total antibodies evaluated by indirect immunofluorescence assay (IFA) were cross reactive; however, neutralizing antibody titers could be detected only against the strain used for infection. Finally, we observed a moderate association between homologous IFN-γ SC and neutralizing antibodies.

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