Differential effects of Th17 cytokines during the response of neutrophils to Burkholderia cenocepacia outer membrane protein A

Abstract

T helper 17 cells are involved in the immunopathology of cystic fibrosis. They play a key role in recruitment of neutrophils, which is the first line of defence against bacteria. Additionally, Burkholderia cenocepacia outer membrane protein A (OmpA) BCAL2958 is considered a potential protective epitope for vaccine development. The present study aimed to investigate the neutrophil response to OmpA in the presence of Th17 cytokines, IL-17 and IL-22 at different times of activation. Neutrophils were isolated from whole blood of healthy volunteers and activated with OmpA in the presence of IL-17, IL-22 or both cytokines together. Supernatant was collected after 1 h, 2 h, 4 h, 8 h, and 12 h. Neutrophil activation was assessed by measuring MPO, TNF-, elastase, hydrogen peroxide, catalase and NO. The results revealed that the combination of IL-17 and IL-22 cytokines induced the release of NE, catalase, H 2 O2 and TNF- from neutrophils activated with Burkholderia OmpA at late stages of activation. However, IL-22 alone or IL-17 alone decreased the myeloperoxidase (MPO), catalase and NE levels at early stages of neutrophil activation. The presence of IL-17 alone led to a significant increase in TNF- level after 1 h and 12 h. However, the presence of IL-22 alone led to a significant increase in TNF- level after only 1 h but a significant decrease after 8 h of activation was observed as compared to OmpA stimulated neutrophils. In conclusion, Th17 cytokines IL-17 and IL-22, have differential effects during the neutrophil response to Burkholderia OmpA.

Keywords

• burkholderia cepacia complex (bcc)
• outer membrane protein a (ompa)
• neutrophils
• t helper 17 cytokines