ABSTRACT
Interleukin (IL)-33, the most recent member of the IL family of cytokines, signals through the ST2 receptor. IL-33/ST2 signaling mediates antigen challenge-induced mechanical hyperalgesia in the joints and cutaneous tissues of immunized mice. The present study asked whether IL-33/ST2 signaling is relevant to overt pain-like behaviors in mice. Acetic acid and phenyl-p-benzoquinone induced significant writhing responses in wild-type (WT) mice; this overt nociceptive behavior was reduced in ST2-deficient mice. In an antigen-challenge model, ST2-deficient immunized mice had reduced induced flinch and licking overt pain-like behaviors. In the formalin test, ST2-deficient mice also presented reduced flinch and licking responses, compared with WT mice. Naive WT and ST2-deficient mice presented similar responses in the rota-rod, hot plate, and electronic von Frey tests, indicating no impairment of motor function or alteration in basal nociceptive responses. The results demonstrate that IL-33/ST2 signaling is important in the development of overt pain-like behaviors.
Subject(s)
Animals , Mice , Hyperalgesia/metabolism , Interleukins/metabolism , Nociceptive Pain/physiopathology , Pain Measurement/methods , Receptors, Interleukin/deficiency , Signal Transduction , Acetic Acid , Benzoquinones , Homozygote , Hot Temperature , Mice, Inbred BALB C , Motor Activity/physiology , Nociception/physiology , Nociceptive Pain/chemically induced , Ovalbumin/immunology , Rotarod Performance TestABSTRACT
Ciprofloxacin, a quinolone with good intracellular penetration may possibly be used for treatment of melioidosis caused by Burkholderia pseudomallei, but problems with resistance may be encountered. Amino acid substitutions in gyrA/gyrB have given rise to fluoroquinolone resistance in various microorganisms. Using published primers for gyrA and gyrB, PCR was performed on 11 isolates of B. pseudomallei with varying degrees of sensitivity to ciprofloxacin, followed by DNA sequencing to detect possible mutations. Results showed an absence of any point mutation in either gene. Local isolates have yet to develop full resistance to ciprofloxacin and probably other mechanisms of resistance may have been involved in the decreased sensitivity to ciprofloxacin.
ABSTRACT
A functional cell mediated immunity (CMI) response was recorded in rats experimentally infected with Taenia taeniaeformis larvae. The presence of CMI was manifested in the delayed type hypersensitivity (DTH) reaction recorded between 12 hours and 24 hours on elicitation with antigen. The time course of the immediate type hypersensitivity (ITH) over 10 weeks showed 2 peaks around the 2nd and the 6th weeks of infection, whereas the DTH response was generally weaker and more uniform over the same time course. Transfer of peritoneal cells from infected rats conferred partial protection to normal recipient rats against a challenge infection. However, optimal protection was only about 50% with transfer of 0.625 X 10(7) cells/rat, and no increase in protection was possible even with transfer of higher cell concentrations.