Hemorrhagic septicemia (HS) is an important infectious disease in cattle and buffaloes, caused by Pasteurella multocida B:2 and E:2. The intranasal recombinant OmpH-based vaccine was successfully used to protect dairy cattle from HS in a previous study. Thus, this study aimed to examine the protective ability of that vaccine among buffaloes. Four groups of Thai swamp buffaloes received different vaccines and were labeled as 100 or 200 μg of the rOmpH with CpG-ODN2007, commercial HS bacterin vaccine, and nonvaccinated control groups. Sera and whole blood were collected to examine the antibody levels and cellular immune response using indirect ELISA and MTT assay, respectively. Challenge exposure was performed with virulent P. multocida strain M-1404 serotype B:2 on day 72 of the experiment. The antibody titers to P. multocida among immunized buffaloes were significantly higher than in the control group (p<0.01), especially the 200 μg of the rOmpH group. The stimulation index (SI) of the intranasally vaccinated groups revealed significantly higher levels than the nonvaccinated group (p<0.01), but not different from the intramuscularly commercial HS vaccine. The clinical signs and high fever were observed after challenge exposure in the nonvaccinated group, while it was not observed among the 200 μg of rOmpH immunized buffaloes. The other immunized groups showed partial protection with transient fever. In conclusion, the rOmpH-based intranasal vaccine could elicit protective ability and induce antibody- and cell-mediated immune response against virulent P. multocida strain among swamp buffaloes.
Chicken heterophils generate reactive oxygen species (ROS) molecules to defend against
invading pathogens. The present study examined effects of quercetin on chicken
heterophils. Heterophils were stimulated with PBS, 50 µM quercetin (QH),
PMA or Escherichia coli (EC) and the resulting intracellular ROS
molecules were determined. Flow cytometry results showed that cells stimulated with QH,
PMA and EC had a higher ROS production. Increases in intracellular ROS molecules were
identified in all treatment groups by fluorescence microscopy. Determination of the
ability of quercetin to manipulate mRNA expression of ROS subunits was assessed using
real-time RT-PCR. Quercetin and other stimulants up-regulated the majority of genes
involved in ROS production: CYBB (NOX2),
NCF1 (p47phox), NCF2
(p67phox), NOX1 and
RAC2. The antioxidant property of QH was explored by measuring mRNA
expression of CAT and SOD1. The data indicate increased
levels of CAT with all treatments; however, only QH attenuated the
expression of the SOD1 gene. To further investigate the effects of
ROS-driven inflammation or cell death, IL6, CASP8 and
MCL1 genes were preferentially tested. The inflammatory gene
(IL6) was profoundly down-regulated in the QH- and PMA-treated groups
while EC induced a strikingly high IL6 expression level. Investigation of
the known apoptotic (CASP8) and anti-apoptotic (MCL1)
genes found down-regulation of CASP8 in the QH- and PMA-treated groups
which were contradicted to the MCL1 gene. In conclusion, quercetin can
enhance ROS production by regulating the expression of genes involved in ROS production as
well as in subsequent processes.
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