Assessment of Pseudomonas aeruginosa Las autoinducer and OdDHL protein conjugate on viability and functional ability of various cells in vitro

Pseudomonas aeruginosa, a major cause of nosocomial infections, has the ability to produce number of factors responsible for its virulence as well as biofilm formation which are regulated by Las and Rhl QS system. The autoinducer OdDHL of las system, play crucial role in pathogenesis of P. aeruginosa. It is involved in induction of factors responsible for the virulence of the organism as well as modulate the host immune responses. In the present study, the effect of KLH OdDHL and BSA OdDHL protein conjugate on various cells in terms of cytotoxicity and phagocytosis was assessed. Concentration of 1µM showed maximum viability of macrophages. Macrophages also showed accelerated phagocytosis, as observed by neutral red assay, which was attributed to the immune-modulatory stimulation provided by the OdDHL conjugate. Other cells like Uroepithelial cells and lymphocytes also showed no significant decrease in cell viability in presence of lower concentrations of conjugated OdDHL. Our Data suggested that interaction of OdDHL conjugated to any of the carrier protein KLH / BSA, with various cells not only improved cell viability but also improved the phagocytic ability of macrophages.