title: Changes in leukocyte subsets of pregnant gilts experimentally infected with porcine reproductive and respiratory syndrome virus and relationships with viral load and fetal outcome.
abstract: In spite of more than two decades of extensive research, the understanding of porcine reproductive and respiratory syndrome virus (PRRSv) immunity is still incomplete. A PRRSv infection of the late term pregnant female can result in abortions, early farrowings, fetal death, and the birth of weak, congenitally infected piglets. The objectives of the present study were to investigate changes in peripheral blood mononuclear cell populations in third trimester pregnant females infected with type 2 PRRSv (NVSL 97-7895) and to analyze potential relationships with viral load and fetal mortality rate. PRRSv infection caused a massive, acute drop in total leukocyte counts affecting all PBMC populations by two days post infection. Except for B cells, cell counts started to rebound by day six post infection. Our data also show a greater decrease of naïve B cells, T-helper cells and cytolytic T cells than their respective effector or memory counterparts. Absolute numbers of T cells and γδ T cells were negatively associated with PRRSv RNA concentration in gilt serum over time. Additionally, absolute numbers of T helper cells may be predictive of fetal mortality rate. The preceding three leukocyte populations may therefore be predictive of PRRSv-related pathological outcomes in pregnant gilts. Although many questions regarding the immune responses remain unanswered, these findings provide insight and clues that may help reduce the impact of PRRSv in pregnant gilts.
authors.affiliation: Department of Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada. andrea.ladinig@vetmeduni.ac.at.
authors.forename: Andrea
authors.initials: A
authors.lastname: Ladinig
authors.forename: Wilhelm
authors.initials: W
authors.lastname: Gerner
authors.forename: Armin
authors.initials: A
authors.lastname: Saalmüller
authors.forename: Joan K
authors.initials: JK
authors.lastname: Lunney
authors.forename: Carolyn
authors.initials: C
authors.lastname: Ashley
authors.forename: John C S
authors.initials: JC
authors.lastname: Harding
mesh_terms: D000034:Abortion, Veterinary / Q000503:physiopathology / Q000821:virology*; D000818:Animals; D005260:Female; D007958:Leukocyte Count / Q000662:veterinary; D007962:Leukocytes / Q000276:immunology*; D007963:Leukocytes, Mononuclear / Q000821:virology; D019318:Porcine Reproductive and Respiratory Syndrome / Q000276:immunology* / Q000821:virology; D019316:Porcine respiratory and reproductive syndrome virus / Q000276:immunology*; D011247:Pregnancy; D013552:Swine; D019562:Viral Load / Q000662:veterinary*