Changes in leukocyte subsets of pregnant gilts experimentally infected with porcine reproductive and respiratory syndrome virus and relationships with viral load and fetal outcome

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.
Source: Veterinary Research - Category: Veterinary Research Source Type: research