SEMIQUANTITATIVE ANALYSIS OF IL-10 PRODUCTION IN BRONCHOALVEOLAR LAVAGE LEUKOCYTES OF PRRSV INFECTED PIGS

Abstract

Semi-quantitative analysis of the interleukin 10 (IL-10) in bronchoalveolar lavage cells (BALC), from pigs challenged with porcine reproductive and respiratory syndrome virus (PRRSV), was undertaken in this study. Twenty-one, three weeks old, crossbred pigs from a PRRSV-free commercial farm were separated into three groups, a control, non-infected group (3 pigs/group), and 2 groups (9 pigs/group), the first inoculated with a Thai-isolated European (O2SB3) strain and the second a Thai-isolated, North American (O1NP1) PRRSV strain. BALC were isolated from three infected pigs and one control on days 5, 9 and 15 post infection (DPI). The levels of IL-10 production in BALC were assessed by RT-multiplex PCR and immunofluorescent assay (IFA). In addition, the BALC were stained and subjected to a differential count. Both groups of PRRSV-infected pigs showed significant upregulation of the increase in IL-10 gene expression and IL-10 positive cells in the BALC after 9 DPI. Both PRRSV strains induced comparable levels of IL-10 production in the infected pigs. Furthermore, the enhanced IL-10 production was observed concurrently with an increased lymphocyte population in BALC