Chemotaxis in response to activation of cells results in -

Ans. is 'b' i.e., Unidirection motion Chemotoxis After extravasation from the blood vessels, leukocytes emigrate in tissues towards the site of injury by chemotoxis. Chemotoxis is unidirectional locomotion oriented along a chemical gradient. o This chemical gradient is created by the substances called chemoattractants (chemotactic agents), which maybe:? I. Exogenous --> Bacterial products 2. Endogenous --> C5a, LTB4, IL-1, TNF, IL-8. Note : C5a is the most powerful chemoattractant. How does chemotactic agents induce chemotaxis ? o Chemotactic agents bind to G-protein coupled recepotors on the surface of leukocytes. o This results in activation of intracellular GTPases. o The GTPases induce polymirization of actin at the leading edge of the cell and reorganization at trailing edge. o Locomotion involves rapid assembly of actin. Remember o Phagocytosis also involves assembly of actin.