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Mediators of Inflammation
Volume 2009, Article ID 394021, 8 pages
http://dx.doi.org/10.1155/2009/394021
Research Article

IL-4 Deficiency Decreases Mortality but Increases Severity of Arthritis in Experimental Group B Streptococcus Infection

Microbiology Section, Department of Experimental Medicine and Biochemical Sciences, University of Perugia, Via del Giochetto, 06122 Perugia, Italy

Received 28 January 2009; Accepted 23 April 2009

Academic Editor: Vera L. Petricevich

Copyright © 2009 Luciana Tissi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

IL-4 is an anti-inflammatory cytokine that inhibits the onset and severity in different experimental arthritis models. Group B streptococci (GBS) have been recognized as an ever-growing cause of serious invasive infections in nonpregnant adults. Septic arthritis is a clinical manifestation of GBS infection. To investigate the role of IL-4 in experimental GBS infection, IL-4 deficient or competent mice were inoculated with GBS/mouse. Mortality, appearance of arthritis, GBS growth in the organs, and local and systemic cytokine and chemokine production were examined. IL-4–/– mice showed lower mortality rates but increased severity of arthritis and exhibited a lower microbial load in blood, kidneys, and joints than wt mice. Increased local levels of IL-1 , IL-6, TNF- , MIP-1 , and MIP-2 accompanied the more severe arthritis in IL-4–/– mice. Our results suggest a detrimental role of IL-4 in GBS sepsis, whereas it plays a beneficial effect on GBS-induced arthritis.