170 likes | 634 Views
LIPOPOLYSACCHARIDE (LPS). By Nawal M.Hijazi October-2004. Role of lipopolysaccharide in the outer membrane. - Permeability barrier - Adhernes and colonization. CHEMICAL NATURE OF LPS.
E N D
LIPOPOLYSACCHARIDE (LPS) By Nawal M.Hijazi October-2004
Role of lipopolysaccharide in the outer membrane • - Permeability barrier - Adhernes and colonization
CHEMICAL NATURE OF LPS • Region I lipid A • Region II core antigin • Region III O polysaccharide
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.
THE O POLYSACCHARIDE &VIRULENCE • -Smoothness • -Resistance to phagocytosis -Protection against complement
LIPID A & VIRULENCE • Production of:- • Cytokin and tumer necrosing factor • Complement cascade • Activation of coagulation cascade Figure.4 Endotoxin and the pyrogenic effect .
LABORATORY IDENTIFICATION OF LPS • Limulus Amoebocyte Lysat (LAL) Assay • Enzyme-linked immunoassay
He who makes no mistakes, make nothing • I thank y0u kindly……………………………