Immunomodulatory roles of quorum-sensing signaling molecules N-acyl homoserine lactones isolated from clinical strain of P. aeuroginosa

Abstract

In Gram negative bacteria the signaling molecule is N-acyl homoserine lactone where carbon chain length varies depending upon the species. Signaling mechanism has effect on many gene expression regulations used to organize and coordinate their multiple virulence determinants as such the production of bioflim, virulence factors required for colonizing and persistence in different environmental conditions. In present study we analyzed the immune responses by an N-acyl homoserine lactone extracted from a multidrug resistant clinical strain which form abundant biofilm. All isolates were positive for biofilm formation with varying intensities. Strain named MM51 which produces abundant and more amount of biofilm compare to other isolates was used to establish its potential effect to modulate immune responses. Result of study showed that N-acyl homoserine lactone MM51 stimulates or reduces antibody production by spleen cells, stimulates immunoglobulin E (IgE) secretion by human B cells, and inhibits cytokines (pg/mL) IFN-γ, IL-4 and IL-5 production by mature monocytes mono Mac 6 cell line. Pseudomonas aeruginosa has multifactorial virulence capability which might be under control of quorum sensing signals acyl homoserine lactones (AHLs). A various studies have already established its role in infection and immune modelling. Natural AHLs are able to make considerable changes in immune responses which also plays role in changing a host protective responses to pathogen protective responses.The study demonstrate that natural AHL has dose depended activity and depending on the concentration.