Assessment of the efficacy of commercial porcine reproductive and respiratory syndrome virus (PRRSV) vaccines based on measurement of serologic response, frequency of gamma-IFN-producing cells and virological parameters of protection upon challenge

Federico A. Zuckermann, Esther Alvarez Garcia, Ivan Diaz Luque, Jane Christopher-Hennings, Alan Doster, Monica Brito, Fernando Osorio

Research output: Contribution to journalArticle

215 Scopus citations

Abstract

The efficacy of two different types of commercial vaccines against PRRSV (Euro-type) was evaluated based on clinical parameters upon challenge as well as post-challenge virological profiles (viremia and viral load in tissues upon necropsy, measured in both cases by quantitative real time PCR). In an attempt to establish correlates of protective immunity, two commonly proposed parameters predictive of immunity were measured: (1) serologic responses (ELISA and neutralizing antibodies), (2) frequency of gamma interferon-producing cells in peripheral blood mononuclear cell fraction. The vaccines compared consisted of two commercially available products that are regularly marketed in Spain: one modified live virus and one killed vaccine. The efficacy assay was carried out by vaccinating twice 3 weeks apart groups of 5 and-a-half month-old female swine and then challenging them with a European type 1 PRRSV strain (Lelystad). The results obtained indicate that the modified live virus vaccine was the only type of vaccine capable of establishing protective immunity, as measured by viral load in blood and tissues. The killed vaccine, in spite of this product evoking a spontaneous interferon-gamma response and post-challenge titers of virus-neutralizing antibody, evoked no measurable protective immunity. In the case of the modified live vaccine, the protection exhibited did not appear to be based on humoral but rather on cell-mediated immunity.

Original languageEnglish (US)
Pages (from-to)69-85
Number of pages17
JournalVeterinary Microbiology
Volume123
Issue number1-3
DOIs
StatePublished - Jul 20 2007

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Keywords

  • Gamma-interferon-producing-cells
  • IL-10
  • Neutralizing antibodies
  • PRRSV
  • Protective immunity
  • Vaccines

ASJC Scopus subject areas

  • Microbiology
  • veterinary(all)

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