Immunological alterations during the clinical and recovery phases of experimental swine dysentery

Abstract

The aim of this study was to examine changes in the systemic immune response during the incubation period and following the onset of clinical swine dysentery, including the recovery period. Ten healthy conventional pigs were inoculated with Brachyspira hyodysenteriae. Blood was sampled at pre-inoculation, at days 4 and 14 post-inoculation, during the first 4 days with clinical signs of dysentery and at days 1, 3, 7, 11 and 15 of the recovery period. Eight pigs developed haemorrhagic diarrhoea. Flow-cytometric analyses of lymphocyte subpopulations showed that all animals, including the two that remained healthy, had an increase in CD8a + CD4 " cells and cd T cells at days 4 and 14 post-inoculation. In addition, an increase in CD4 + CD8a + cells and CD8a + CD8b + cells was observed at days 4 and 14 post-inoculation in animals that developed dysentery. During clinical signs of dysentery, the acute-phase protein serum amyloid A was increased. There was a two-to threefold increase in both neutrophils and monocytes during signs of dysentery and at the beginning of the recovery period. The numbers of CD8a + CD8b " CD4 " , CD45RA " lymphocytes also increased during the dysentery period. Circulating CD21 + cells and CD21 + CD45RA " cells decreased at the end of the incubation period, during signs of dysentery and at the beginning of the recovery period. The dysentery-affected animals developed antibodies to B. hyodysenteriae-specific antigens (~16 kDa and~30 kDa) from the first day of recovery, and cd T cells showed an increase during the recovery period. In comparison with pre-inoculation, increased numbers of monocytes, neutrophils, CD8a + CD8b " CD4 " lymphocytes and CD45RA " lymphocytes were observed during clinical dysentery. Increased numbers of neutrophils, cd T cells and specific antibodies were seen during the recovery period. Taylor and Alexander (1971) showed that swine dysentery is caused by the Gram-negative spirochaete Brachyspira hyodysenteriae. The main clinical signs are severe mucohaemorrhagic diarrhoea and a reduced general appearance. The typical manifestations in the large intestine are excessive mucus production, haemorrhage and tissue necrosis. Due to the increased antimicrobial resistance of B. hyodysenteriae to the few antibiotic treatments available (Lobova et al., 2004), a better knowledge of the host responses during infection is essential for development of prophylactic measures. In pigs, macrophages and neutrophils are found in colonic lesions at later stages of swine dysentery, but the role of these cells is still unclear (Albassam et al., 1985). Experimental infections with B. hyodysenteriae in mice demonstrate that neutrophils are of great importance in mediating the severe oedema and structural lesions that occur in the intestine during the infection , and may thus be part of the pathogenesis. However, the commensal intestinal flora has also been shown to be necessary for the development of the disease (Whipp et al., 1979; Neef et al., 1994). Among lymphocyte subsets, CD8 + cells appear ...

Characteristics of Circulating T Cell Receptor γδ T Cells from Individuals Chronically Infected with Hepatitis B Virus (HBV): An Association between Vδ2 Subtype and Chronic HBV Infection

“…There is further evidence that IFN-␥ is a key molecule in the immune response against viral infection [25], and our results indicate that chronic HBV infection may actually damage TCR␥␦ T cell immune function, as indicated by IFN-␥ production and cytotoxic activity. Some studies in animal models have indicated that the cytotoxic activity of TCR␥␦ T cells is improved during Salmonella infections, but, for some autoimmune diseases in humans, TCR␥␦ T cells remain dysfunctional in order to avoid a hyperstrong immune response [22][23][24][25][26][27][28]. We could not confirm whether the basis for dysfunctional TCR␥␦ T cells in patients with HBV infection is the same as that observed in autoimmune diseases.…”

“…Active TCR␥␦ T cells display nonspecific cytotoxicity against targets without major histocompatibility complex (MHC) restriction [22,23]. Thus, we obtained TCR␥␦ T cells from the peripheral blood by FACS and activated these cells with anti-V␥␦ antibody and rhIL-2.…”

ENteric Immunity SImulator: A Tool for In Silico Study of Gastroenteric Infections

“…The middle panel shows the system response to the addition of 30 individuals in the Bf_lumen state, representing B. hyodysenteriae , on days 1, 2, and 3. The dynamics observed are in agreement with those seen experimentally in pig infections [52], [53] and generally expected with three distinct phases; i ) the acute inflammation ( days 1–6) marked by an increase in k eDC (not shown) and k Th [Fig. 10(d)], followed by epithelial damage [Fig.…”

“…Parameter values for this demonstration are listed in Table IV and were assigned according to published observations of interactions between bacteria of the Brachyspira genus and immune cells or were fit to cell population dynamics reported in animal infection models [52], [53]. Parameter space was reduced by simplifying assumptions.…”

Enhanced Peripheral γδT Cells Cytotoxicity Potential in Patients with HBV-Associated Acute-On-Chronic Liver Failure Might Contribute to the Disease Progression

“…Therefore, these results demonstrated increased cytotoxic potential of γδ T cells in HBV-ACLF. Some other studies also indicated that the cytotoxicity activity of γδ T cells was improved in salmonella infections or other infection diseases [17][18][19][20][21]. In our study, IFN-γ, TNF-α, or IL-17 cytokine production was determined in both the αβ T-cells and the γδ T cells in some HBV-ACLF patients, and the results suggested that the γδ T cells were more powerful in cytokine production than αβ T-cells (Supplementary Figure 2) .…”