IMMUNOMODULATORY EFFECT OF Escherichia coli LIPOPOLYSACCHARIDE ON PHENOTYPE AND FUNCTION OF BLOOD MONOCYTES IN CAMELS

Jamal Hussen1*, Khaled R. Alkharsah2, Ibrahim Hairul-Islam M3 and Naser Abdallah Al Humam1
1Department of Microbiology, College of Veterinary Medicine, 3Biological Sciences Department,
College of Science, King Faisal University, Al-Ahsa, Saudi Arabia
2Department of Microbiology, College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia

ABSTRACT

The objective of the current study was to investigate the effect of lipopolysaccharide (LPS) from E. coli on the phenotype and the function of the camel monocytes. Flow cytometry was used to analyse the expression of different myeloid markers and cell adhesion molecules on camel monocytes and to evaluate the ability of monocytes to engulf bacteria and to generate reactive oxygen species (ROS). In LPS-stimulated blood, monocytes showed shifting toward inflammatory macrophage-1 (M1) profile by enhancing the expression of high levels of MHCII molecules and reduced levels of CD163. Furthermore, LPS-stimulated monocytes upregulated the expression of the adhesion molecules CD62L and CD11b while downregulated the expression of CD18. Functionally, stimulation with LPS reduced the phagocytosis capability of monocytes but enhanced their ability to produce ROS. These results suggest a modulating effect of LPS on the phenotype, adhesion, and phagocytic functions of the camel blood monocytes and propose a possible new immune evasion mechanism.
Key words: Adhesion molecules, camel, innate immunity, monocytes, lipopolysaccharide, phagocytosis, ROS