1. 1 LIPOPOLYSACCHARIDE (LPS) By Nawal M.Hijazi October-2004

2. 2 Role of lipopolysaccharide in the outer membrane - Permeability barrier - Permeability barrier - Adhernes and colonization - Adhernes and colonization

3. 3 CHEMICAL NATURE OF LPS Region I lipid A Region I lipid A Region II core antigin Region II core antigin Region III O polysaccharide Region III O polysaccharide

4. 4 CHEMICAL NATURE OF LPS Figure 3. Glc = glucose; GlcNac = N-acetyl- glucosamine; Gal = galactose; Hep = heptose; P = phosphate ; Etn = ethanolamine; R1 and R2 = phoshoethanolamine or aminoarabinose. Ra to Re indicate incomplete forms of LPS. The Rd2 phenotype (not shown) would have only a single heptose unit. The Rc, Rd2, and Rd1 mutants lack the phosphate group attached to Hep.

5. 5 THE O POLYSACCHARIDE &VIRULENCE -Smoothness -Smoothness -Resistance to phagocytosis -Resistance to phagocytosis -Protection against complement

6. 6 LIPID A & VIRULENCE Production of:- Production of:- Cytokin and tumer necrosing factor Cytokin and tumer necrosing factor Complement cascade Complement cascade Activation of coagulation cascade Activation of coagulation cascade Figure.4 Endotoxin and the pyrogenic effect.

7. 7 LABORATORY IDENTIFICATION OF LPS Limulus Amoebocyte Lysat (LAL) Assay Limulus Amoebocyte Lysat (LAL) Assay Enzyme-linked immunoassay Enzyme-linked immunoassay

8. 8 He who makes no mistakes, make nothing I thank y0u kindly …………………………… I thank y0u kindly ……………………………