TY - JOUR
T1 - 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
AU - Zuckermann, Federico A.
AU - Garcia, Esther Alvarez
AU - Luque, Ivan Diaz
AU - Christopher-Hennings, Jane
AU - Doster, Alan
AU - Brito, Monica
AU - Osorio, Fernando
N1 - Funding Information:
We appreciate the help of Kandy Lytle for her contribution of excellent and conscientious animal care procedures at the animal facilities of the Department of Veterinary and Biomedical Sciences at the University of Nebraska. This research has been partially supported by: (1) a grant (to FO) from the National Pork Board od the Unites States (NPB No. 04-112), (2) by a subcontract (to FO) from a NRICGP-USDA Integrative Program Award to University of Minnesota (PI Dr. M. Murtaugh) and also by (3) a grant from the University of Illinois State Experimental Station in fulfillment of NC-229 Regional Research Project participation (to FZ). EAG and IDL were the recipients of external pre-doctoral fellowships awarded by the Ministerio de Educación y Ciencia of Spain and by the Generalitat de Catalunya respectively. All the animal experiments described in this paper were reviewed and approved by the Institutional Animal Care Committee of the University of Nebraska-Lincoln under IACUC Protocol No. 05-01-002. This publication has been authorized by the Dean of the Agricultural Research Division of the Institute of Agriculture and Natural Resources of the University of Nebraska-Lincoln.
PY - 2007/7/20
Y1 - 2007/7/20
N2 - 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.
AB - 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.
KW - Gamma-interferon-producing-cells
KW - IL-10
KW - Neutralizing antibodies
KW - PRRSV
KW - Protective immunity
KW - Vaccines
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U2 - 10.1016/j.vetmic.2007.02.009
DO - 10.1016/j.vetmic.2007.02.009
M3 - Article
C2 - 17376612
AN - SCOPUS:34250187408
SN - 0378-1135
VL - 123
SP - 69
EP - 85
JO - Veterinary Microbiology
JF - Veterinary Microbiology
IS - 1-3
ER -