Chemotaxis is mediated by-

Chemotaxis is unidirectional locomotion of leukocytes towards the site of injury, oriented along a chemical gradient. This chemical gradient is created by substances called chemoattractants (chemotactic agents), which may be exogenous (bacterial products) or endogenous (C5a, LTB-4, IL-I, TNF, IL-8). C5a is the most powerful chemo-attractant (chemokine REF: ROBBINS pathology 10th edition