innate

Type in the content of your new page here. o **//C3 convertase//**—complex with C3**////** o C13 has C5 as substrate, resulting in conversion of C5 to C5a & C6b. o **//C5 convertase//**—complex with C5 o Can activate heparin, DNA or RNA, C-reactive protein (↑ in blood during inflammation) o C3b inactivated by protein factor H & I · **//Lectin pathway//**—activated by bacterial carbohydrates o Antibody-independent o Activated by plasma protein **//Mannose-binding lectin (MBL)//** § Activate C4 & C2 to create C3 convertase · **//Alternative pathway//**—activated by gram-negative bacterial & fungal cell wall polysaccharides o Initiated by lipopolysaccarides (endotoxin) on bacterial surface, yeast cell wall carbohydrates (zymosan) that bind C3b & protect it from factor H and destruction. C3b can then react factor B. Then recognized by enzyme, factor D, which activates factor B, producing factor Bb. Now have unstable C3b/Bb until bind with properdin (P). C3b/Bb/P produces C3b, resulting in C3b/Bb/P/C3b that is C5 convertase converging alternative pathway with classic pathway · Opsonization · Anasphylatoxic activity resulting in mast cell degranlation · Leukocyte chemotaxis
 * Cascade continue to form **//membrane attack complex//** (MAC), creating pores in bacteria membrane, influx of water & ions, resulting in **//cell lysis//** and destruction of pathogen.
 * Most important **//Opsonin//** tag pathogenic organism for destruction
 * C4a are **//anaphylatoxins//** that induce rapid **//degranulation//** & histamine release from mast cells causing vasodilation & ↑capillary permeability
 * C5a is major chemotactic factor for neutrophils
 * **//Chemotactic factor//** attracts leukocytes to site of inflammation
 * Anaphylatoxic activity necessary in early inflammation close to site to induce mast cell degranulation & ↑ # of soluble mediators to enhance permeability & vasodilation.
 * Chemotactic activity require longer period & distal to inflammatory site to attract leukocytes from circulation
 * **//Caroxypeptidase//**—plasma enzyme removes terminal arginine on both peptides producing C3a desArg & C5a desArg which preserve healthy tissue
 * C3b can break down diminishing biologic activity.
 * Complement cascades can be activated by 3 different means and its products have 4 functions.