Question

List and describe the four major steps in leukocyte extravasation from the bloodstream to sites of infection in the tissue. Include the triggers and features of endothelial cell activation that facilitate the initiation of leukocyte extravasation and migration.

Name the region of the antibody that determines their effector function and list the 5 main types. List and explain the three main effector functions mediated by this region of the antibody.

Answer 1

of the circulatory sys Leukocyte Extravasion | Diapedesis It is the movement of leukocytes out be coculatory system and towards the site of tissue damage of Infechon. process forms past of the innate une response involving the recruitment of non-specific leukocytes. 4 steps O chemoattraction © Roling adhesion © Tight adheson © Endothelial Taansmigration chemoattaachon By recognition and activation by pathogens resident macrophages to the affected tissue release cytokines such as IL-1 TNF a and chemokines IL-1 TNF a cause endothelial cells of blood vessels Dear the site of infection to express cellular adhesion molecule Roling adbesion carbohydrate ligands on the circulat leukocytes band to selection molecules on the inner wall of the vessel with marginal affinity. This causes leucocyt

to slow down and begin rolling down in the imper surface of the vessel coll Dulang this rolling mohon transitory bonds are formed and booken between Selectens and theio ligands. Tight adbesion Chemokines released by macrophage activates the roling leuwagles and cause Sualace integrin molecules to suutch foom the default cowl affinity state to a high affinity state. This is assisted througb juxtacarne activation of integins by chemokines and soluble factors released by endothelial cells. In the activated state Integans bind tightly to complementary receptors expressed on endothelial cells with high affinity. Transmigralon The cytoskelton of the leukocytes are reoag- anized in such a way that the leukocytes are spread out over the endothelial cells. leucocyles extend pseudopodia and pass through gaps between endothelial cells. This passage of cells the ough the intact vessel wall is called diapedesis.

B2 Intequins on poling leukocytes bird endothelial cellular adhesion molecules, doreshng cell movement. cellular activator via extracellular chemokines cames poefoomed Ba Integains to be released foom cellular stores. Integrin molecules + migrale to the cell surface and J congregoale in high avidity patebes. - Senim containing anhigen specific anthodlies is called cushisenem. The 5 types are IgG, IgM, IgA, lgp and IgG They . gde classified according to the type Of heavy choren constant region and are distabuted and frenchon differently 6 body Ashbodiese block ugand receptor anteaed - cause cell lyse through activation of complement dependant cytotoxicity (CDC): - They will interact with fe receptors on effect or cell to engage antibody depender cellular cytotoniaty. By coating the pathogen antibodies tog ghmulate effector function against the pathogen in cell that recognize coated pathogen have fc receptor bicyce the tes CamScanner

LFA-1-ICAM1/2 VLA4-VCAM L-Soloctin E/P-Sepectin-PSGL1 PECAM CD99 JAM ESAM Mac-1-ICAM1 eukocytes Blood vessel Capture rolling Adhesion Crawling Diapodesis Paracellular transcellular Floating CS ScaEnde hediat cells CamScanner Pericytes Basement membrane Tissue