Comparative study of immune responses elicited by outer membrane vesicles of different Pseudomonas aeruginosa strains

Abstract

BackgroundPseudomonas aeruginosa (P. aeruginosa) is an opportunistic mucosal human pathogen that naturally releases outer membrane vesicles (OMVs) in different environments, as do other Gram-negative bacteria. The intestinal tract infections caused by P. aeruginosa increase the risk of respiratory infections and mortality of other diseases related to gut infections. Therefore, in this study, we attempted to investigate toll-like receptor (TLR) signaling pathways and immune response profiles of human colon adenocarcinoma (Caco2) cell line exposed to the OMVs of three different P. aeruginosa strains (i.e., antibiotic-susceptible, multi-drug resistant (MDR), and standard lab ATCC 17933). Materials and methodsReal-time quantitative reverse transcription PCR array was carried out to determine mRNA expression in 84 TLRs signaling pathway genes, and the production of specific cytokines was measured by ELISA. ResultsOMVs of different strains could induce unique changes in regulating TLRs signaling pathways, such that there were remarkable differences in pro-inflammatory effects and anti-inflammatory responses among the three strains. ConclusionThe more complete immune responses observed through the MAMPs caused by MDR strain OMVs interactions with Caco2 lead us to the conclusion that the use of MDR or cystic fibrosis strain OMVs for better known the host immune responses seems preferable.