Cell-mediated and humoral immune responses in pigs following primary and challenge-exposure to Lawsonia intracellularis

Abstract

To investigate immune responses upon re-infection with Lawsonia intracellularis, local and peripheral humoral and cell-mediated immune responses to primary and challenge inoculations were studied in 22 pigs. Pigs were orally inoculated with virulent L. intracellularis at the age of 5-6 weeks, treated with antibiotics and challenged with a re-inoculation (RE) at the age of 12 weeks. Treatment control (TC) pigs received only the primary inoculation and challenge control (CC) pigs received only the secondary inoculation at 12 weeks of age. Following this regimen, all RE pigs were protected against the re-infection as defined by reduced colonisation and pathology of intestinal mucosa, absence of bacterial shedding and without increase in serum acute phase protein response. In the protected RE pigs, serum IgG responses were variable with both high and low responders. Serum IgA responses were not boosted by the re-inoculation, since identical intestinal IgA responses developed in response to the inoculation in both the susceptible CC pigs and the protected RE pigs. A memory recall cell-mediated immune response developed in RE pigs which was significantly stronger compared to the primary response in age-matched CC pigs as assessed by whole blood IFN-γ assay and by calculation of IFN-γ integrated median fluorescence intensity (iMFI) after flow cytometry. The major IFN-γ producing cells were identified as CD8+ and CD4+CD8+ double positive lymphocytes. The results indicate that cell-mediated immune responses are likely mediators of protective immunity against L. intracellularis, with CD8+ effector cells and CD4+CD8+ double positive memory T cells as main contributors to the antigen-specific IFN-γ production.

Low CD4/CD8 ratio in classical swine fever postnatal persistent infection generated at 3 weeks after birth

“…This phenomenon is associated with chronic and persistent infections, such as hepatitis C virus (HCV) and human immunodeficiency virus (HIV) infection (Dustin, 2017;Ferrando-Martinez et al, 2011;Serrano-Villar, Moreno et al, 2014;. Previous reports assert that CD4/CD8 ratio values around 1 correlated with the generation of an effective immune response in swine (Appleyard, Furesz, & Wilkie, 2002;Cordes, Riber, Jensen, & Jungersen, 2012). Accordingly, the CD4/CD8 ratio values in the CSFV seropositive pigs were around 1.…”

Carbopol improves the early cellular immune responses induced by the modified-life vaccine Ingelvac PRRS® MLV

“…Gene set enrichmentbased approach has been used to develop predictors of human vaccine outcome, suggesting the genetic background as determinant in inducing immune responses (Tan et al, 2014). Evidence for the impact of genetic variation exists also for a number of livestock diseases (Glass et al, 2012 andCordes et al, 2012). In addition to histocompatibility genes, microarray analysis showed transcriptional differences in several immune-related genes between high and low responders (Nino-Soto et al, 2008).…”

Efficient priming of CD4 T cells by Langerin-expressing dendritic cells targeted with porcine epidemic diarrhea virus spike protein domains in pigs

“…• C. Plates were washed and blocked with 150 L 5% non-fat milk for 2 h at 37 • C. Diluted sera (1:400) and undiluted fecal extracts were applied in duplicate and incubated at 37 • C for 1 h. Pig fecal extracts were prepared as previously described (Cordes et al, 2012). Wells were extensively washed and incubated with 100 L secondary conjugates (Horse Radish Peroxidase (HRP)-conjugated anti-pig IgG (Santa Cruz Biotech) or anti-pig IgA (Bethyl) at 37 • C for 1 h. Wells were extensively washed and incubated with 100 L HRP substrate (KPL) for 5 min, and the reaction was stopped with 1N HCl.…”