The IL-27 Receptor Chain WSX-1 Differentially Regulates Antibacterial Immunity and Survival during Experimental Tuberculosis

Abstract

IL-12 is a potent inducer of IFN-γ production and promotes a protective cell-mediated immune response after Mycobacterium tuberculosis infection. Recently, the IL-12-related cytokine IL-27 was discovered, and WSX-1 was identified as one component of the IL-27R complex. To determine the functional significance of IL-27/WSX-1 during tuberculosis, we analyzed the course of infection and the immune response in WSX-1-KO mice after aerosol infection with M. tuberculosis. In the absence of WSX-1, an increased production of the proinflammatory cytokines TNF and IL-12p40 resulted in elevated CD4+ T cell activation and IFN-γ production, which enhanced macrophage effector functions and reduced bacterial loads. This is the first occasion of a selectively gene-deficient mouse strain showing higher levels of protective immunity against M. tuberculosis infection than wild-type mice. However, a concomitantly increased chronic inflammatory response also accelerated death of infected WSX-1-KO mice. In vitro, IL-27 induced STAT3 phosphorylation and inhibited TNF and IL-12 production in activated peritoneal macrophages, indicating a novel feedback mechanism by which IL-27 can modulate excessive inflammation. In conclusion, IL-27 both prevents optimal antimycobacterial protection and limits the pathological sequelae of chronic inflammation.

Interleukin‐15 mediates protection against experimental tuberculosis: A role for NKG2D‐dependent effector mechanisms of CD8+ T cells

“…Mtb (H37Rv) was grown and maintained as described previously [55]. Aerosol infection of experimental animals was performed using an inhalation exposure system (Glas-Col, Terre-Haute, IN) [55]. …”

“…To analyse proliferation of T cells in lungs from infected mice, 1 mg BrdU (BD Biosciences) was i.p. injected 3 days prior to analysis and single-cell suspensions were prepared and processed as described [55]. Apoptotic T cells in lungs from infected mice were detected by staining single-cell suspensions with FITC-labelled annexin V (BD Biosciences) and PI (BD Biosciences).…”

“…After reverse transcription into cDNA, gene expression was quantified using a Light Cycler (Roche) [55]. The following primer pairs were used: IFN-c: sense 5 0 -GCTCTGAGACAATGAACGCT-3 0 , antisense 5 0 -AAAGAGATAATCTGGCTCTGC-3 0 ; perforin: sense 5 0 -AATATCAATAACGACTGGCGTGT-3 0 , antisense 5 0 -CATGTTTGCCTCTGGCCTCCTA-3 0 ; granzyme B: sense 5 0 -TGCTGCTCACTGTGAAGGAA-3 0 , antisense 5 0 -TTACCATAGG-GATGACTTGCTG-3 0 ; FasL: sense 5 0 -CCGGTGGTATTTATGGT-3 0 , antisense 5 0 -CTTTGGTTGGTGAACTC-3 0 ; TNF: sense 5 0 -TCTCATCAGTTCTATGGCCC-3 0 , antisense 5 0 -GGGAGTAGA-CAAGGTACAAC-3 0 ; b2 m: sense 5 0 -TCACCGGCTTGTATGC-TATC-3 0 , antisense 5 0 -CAGTGTGAGCCAGGATATAG-3 0 .…”

“…All experimental and animal handling procedures were in accordance with the German Animal Protection Law and were approved by the Animal Research Ethics Board of the Ministry of Environment (Kiel, Germany). Mtb (H37Rv) was grown and maintained as described previously [55]. Aerosol infection of experimental animals was performed using an inhalation exposure system (Glas-Col, Terre-Haute, IN) [55].…”

“…For stimulation of IFN-c production, enriched CD4 + or CD8 + T cells were incubated with peritoneal macrophages that were pulsed with 25 lg/mL short-term culture filtrate from Mtb (a kind gift of Peter Andersen, Statens Serum Institut, Copenhagen, Denmark) in Iscove's modified Dulbecco's medium. After 72 h of restimulation, supernatants were collected and frozen at -80 C until production of IFN-c was quantified by ELISA [55]. To measure the cytotoxic activity of enriched CD8 + T cells, a 5-h 51 Cr (Amersham, Freiburg, Germany) release assay using Mtb short-term culture filtratestimulated peritoneal macrophages as target cells at various effector-to-target ratios was employed.…”