SELECTION OF OPTIMAL PARAMETERS AND REVISITING FUNCTIONAL CHARACTERIZATION OF CXCR1 IN RESPONSE TO STAPHYLOCOCCUS AUREUS INFECTION

Puja Dutta and Biswadev Bishayi*

ABSTRACT

Staphylococcus aureus, a major opportunistic pathogen, can cause spacious range of infections in animals and humans. Treatment of S.aureus induced sepsis and inflammatory diseases have become the need of the hour. S.aureus stimulated murine peritoneal macrophages releasesa major chemokine, CXCL8 and aggravate CXCR1 expression on the macrophage surface. CXCL8/CXCR1 axis is pivotal for leucocyte recruitment and bacterial clearance from the site of infection. Extrapolating our previous research works, the effect of gradedbacterial inoculum size and peritoneal macrophage cell count on CXCL8, ROS generation, and CXCR1 expression had been evaluated. Secondly, based on the optimum doses obtained, kinetic-dependent S.aureus infection on CXCR1 expression, its subsequent effect on bacterial phagocytic phenomenon had also been studied. The bacterial inoculums size and macrophage quantity had a regulatory effect on CXCR1 expression on the macrophage surface. Increasing bacterial inoculum or macrophage quantity in the culture medium does not elevate CXCR1 expression on macrophage surface beyond a certain point, suggesting a reconcilable interaction between bacterial components and macrophage essential for receptor expression. According to the results obtained, maximum intracellular phagocytosis occurred at 60 minutes post infection. The magnitude of phagocytic activity wasfound roughly proportional to the surface CXCR1 expression on macrophage surface. Hence CXCL8/CXCR1 axis has a significant role in intracellular bacterial phagocytosis and serves as a potential therapeutic target to control S.aureus infection.

Keywords: CXCL8; CXCR1; peritoneal macrophage; phagocytosis; Staphylococcus aureus.