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Differential expression of sheep beta-defensin-1 and -2 and interleukin 8 during acute Mannheimia haemolytica pneumonia
Journal article   Open access   Peer reviewed

Differential expression of sheep beta-defensin-1 and -2 and interleukin 8 during acute Mannheimia haemolytica pneumonia

Mark R Ackermann, Jack M Gallup, Joseph Zabner, Richard B Evans, Charles W Brockus, David K Meyerholz, Branka Grubor and Kim A Brogden
Microbial pathogenesis, Vol.37(1), pp.21-27
2004
DOI: 10.1016/j.micpath.2004.04.003
PMID: 15194156
url
https://doi.org/10.1016/j.micpath.2004.04.003View
Published (Version of record) Open Access

Abstract

Beta-defensins are antimicrobial peptides produced by several cell types, including respiratory epithelia and leukocytes. Expression of some beta-defensins is increased by bacterial-induced inflammatory responses whereas expression of other beta-defensins is constitutive. Two beta-defensins are expressed in lungs of sheep (sheep beta-defensin-1 and -2; SBD-1/-2) and expression of SBD-1 is increased during parainfluenza virus type 3 (PI-3) infection. The effect of Mannheimia haemolytica, a Gram-negative bacteria known to induce expression of bovine beta-defensins and NF-kappa B in lung, has not been determined for SBD-1/-2. In this study, different concentrations of M. haemolytica were inoculated into pulmonary bronchi of lambs. SBD-1 and SBD-2 mRNA levels detected by real time reverse transcriptase polymerase chain reaction in lung homogenates did not increase. In fact, SBD-1 mRNA levels were significantly decreased with the highest administered inoculum concentration (10 9). In contrast, mRNA levels of interleukin-8 (IL-8) were significantly increased over controls and progressively increased with M. haemolytica concentrations. Co-inoculation of M. haemolytica with xylitol, an osmotic agent, did not alter mRNA levels of SBD-1, SBD-2 or IL-8. SBD-1 mRNA expression was detected in lung epithelia, but not in leukocytes. This study suggests that SDB-1 expression occurs in epithelia and decreases during severe bacterial pneumonia, which is in contrast to the increase that occurs with PI-3 infection.
Mannheimia haemolytica Innate immunity Pneumonia Sheep beta-defensin Interleukin-8 Antimicrobial peptides

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