Salmonella enterica serovar Typhimurium infection-induced CD11b+ Gr1+ cells ameliorate allergic airway inflammation
Allergies are mainly characterized as an unrestrained Th2 biased immune response. Epidemiological data associate protection from allergic diseases with the exposure to certain infectious agents during early stages of life. Modulation of the immune response by pathogens has been considered to be a major factor influencing this protection. Recent evidence implicates that immunoregulatory mechanisms induced upon infection, ameliorate allergic disorders. A longitudinal study has demonstrated reduced frequency and incidence of asthma in children who reported a prior infection with Salmonella. Experimental studies involving Salmonella Typhimurium infected murine models have confirmed protection from induced allergic airway inflammation; however, the underlying cause leading to this amelioration remains incompletely defined. In this study, we aimed to delineate the regulatory function of Salmonella Typhimurium infection in the amelioration of allergic airway inflammation in mice. We observed a significant increase in CD11b+Gr1+ myeloid cell population in mice after infection with S. Typhimurium. Using in vitro and in vivo studies we confirmed that these myeloid cells reduce airway inflammation by influencing Th2 cells. Further characterization showed that the CD11b+Gr1+ myeloid cells exhibited their inhibitory effect by altering GATA-3 expression and IL-4 production by Th2 cells. These results indicate that the expansion of myeloid cells upon S. Typhimurium infection could potentially play a significant role in curtailing allergic airway inflammation. These findings signify the contribution of myeloid cells in preventing Th2 mediated diseases and implicate their possible application as therapeutics.
Citation: Infect Immun. 2014 Mar;82(3):1052-63. doi: 10.1128/IAI.01378-13. Epub 2013 Dec 16.
Publication Type: Journal article
Publisher: Infection and Immunity