Fig. 2: The Harmful Effects of Peptidoglycan Fragments
and Lipoteichoic Acid Released During Gram-Positive Infections

The lysis of gram-positive bacteria causes them to release peptidoglycan fragments and lipoteichoic acids from their cell wall. These cell wall components, in turn, bind to toll-like receptors such as TLR-2 and TLR-6 that are specific for these cell wall components and are found on the surface of body defense cells called macrophages.This triggers the macrophages to release various defense regulatory chemicals called cytokines, including IL-1, IL-6, IL-8, TNF-alpha, and PAF. The cytokines then bind to cytokine receptors on target cells stimulating the production of inflammatory mediators such as prostaglandins and leukotrienes as well as activating both the complement pathways and the coagulation pathway. Excessive production of clotting factors may lead to ARDS and DIC while an overproduction of prostaglandins, leukotrienes, and complement proteins can damage the vascular endothelium resulting in shock and MSOF.

(LPS, lipopolysaccharide; IL-1, interleukin-1; IL-6, interleukin-6; IL-8, interleukin-8, TNF-alpha, tumor necrosis factor-alpha; PAF, platelet-activating factor; ARDS, acute respiratory distress syndrome; DIC, disseminated intravascular coagulation; MSOF, multiplesystem organ failure.)

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