acyl homoserine lactones from culture supernatants of pseudomonas aeruginosa accelerate host immunomodulation酰基高丝氨酸内酯文化上层清液的铜绿假单胞菌促进宿主免疫调节.pdfVIP

Acyl Homoserine Lactones from Culture Supernatants of Pseudomonas aeruginosa Accelerate Host Immunomodulation Ravi Kumar Gupta, Sanjay Chhibber, Kusum Harjai* Department of Microbiology, Bio Medical Sciences Block, Panjab University, Chandigarh, India Abstract The virulence of Pseudomonas aeruginosa is multifactorial and under the control of quorum sensing signals, such as acyl homoserine lactones (AHLs). The importance of these molecules in the establishment of infection has been previously reported. These molecules either improve the virulence potential of P. aeruginosa or modulate the host immune response. To establish the immune modulating potential of quorum sensing signal molecules, previous studies have only used synthetic AHLs. However, there can be differences in the biological properties of synthetic and natural AHLs. The use of naturally extracted AHLs from the culture supernatant of P. aeruginosa is likely to simulate natural conditions more than the use of synthetic AHLs. Therefore, in the present study, the immune modulating potential of synthetic and naturally extracted AHLs was compared using a thymidine uptake assay, immunophenotyping and sandwich ELISA in order to assess mouse T-cell proliferation and production of Th1 and Th2 cytokines. Natural AHLs were able to suppress T-cell proliferation, even at low concentrations, compared to synthetic AHLs. The majority of cells undergoing proliferation were CD4+, as revealed by immunophenotyping. The inhibition of T-cells was stronger with natural AHLs compared to synthetic AHLs. Moreover, the natural AHLs were also able to shift immune responses away from host protective Th1 responses to pathogen protective Th2 responses. Citation: Gupta RK, Chhibber S, Harjai K (2011) Acyl Homoserine Lactones from Culture Supernatants of Pseudomonas aer