Antibody production and blastogenic response in pigs experimentally infected with porcine reproductive and respiratory syndrome virus.
Seven five-week piglets were infected intranasally with 10(5) TCID50 of porcine reproductive and respiratory syndrome (PRRS) virus strain IAF.exp91. All virus-exposed pigs developed fever, labored abdominal breathing, conjunctivitis, and lymph node enlargement within the first 96 h postexposure (PE), which continued to d 10 to 14 PE. Two pigs that were necropsied at d 7 and 10 PE had diffuse interstitial pneumonitis, cardiopathy and lymphadenopathy. All 5 remaining pigs produced serum IgM and IgG antibodies against PRRS virus by 7 or 14 days PE, as demonstrated by indirect immunofluorescence. This corresponded with the capability of isolating the virus from serum d 7 to d 49 or d 63 PE. Low serum neutralizing antibody titers were detected in 3 of the virus-exposed pigs by 35 days PE. A transient episode of diminished proliferative response of peripheral blood lymphocytes to mitogens phytohemagglutinin (PHA) and concanavalin A (Con A) was observed in the virus-exposed pigs at d 3 PE. However, in vitro spontaneous uptake of [3H]-thymidine was significantly increased in lymphocyte cultures of the same pigs at d 7 or d 14 PE. These results suggest polyclonal activation of peripheral blood lymphocytes.
Vézina
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SA
Université du Québec à Montréal, Département des Sciences Biologiques, Succursale Centre-Ville, Québec.
Loemba
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Fournier
M
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Dea
S
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Archambault
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D
D000818:Animals; D000914:Antibodies, Viral / Q000096:biosynthesis / Q000097:blood; D000917:Antibody Formation; D018174:Arterivirus Infections / Q000276:immunology / Q000473:pathology / Q000662:veterinary*; D003208:Concanavalin A; D019084:Fluorescent Antibody Technique, Indirect; D066298:In Vitro Techniques; D008198:Lymph Nodes / Q000473:pathology; D008213:Lymphocyte Activation; D010835:Phytohemagglutinins; D012016:Reference Values; D013552:Swine; D013553:Swine Diseases; D013997:Time Factors
D000914:Antibodies, Viral; D010835:Phytohemagglutinins; D003208:Concanavalin A