Pseudomonas aeruginosa is a gram-negative, aerobic, non-spore forming rod which is capable of causing a variety of infections in both immunocompetent and immunocompromised hosts. Quorum sensing (QS) is the process through which gram-negative bacteria control the expression of the proinflammatory genes based on cell density, that allows communication and signaling between cell and bacteria. Our study was focused on the modulatory role of QS against inflammation in different immune cell cultures in vitro including splenocytes, lymphocytes and Bone marrow. The results of the current study suggested an immune modulatory role of QS against all inflammatory markers of interest including NF_KB, IL-2 ,IL-6, IL-1β  and TNFα where all of these markers were downregulated in QS treated groups compared with the control group (untreated group). The results of our study indicated that the response started from the lowest amount of QS which was 5%, while the downregulation was shown with the highest concentration of QS which was 25%. All in all, our results suggested an anti-inflammatory role of QS which may be lead to a future investigation about their future role as a targeted therapy against inflammation.