Receptors that mediate this process trigger both a fast, excitatory signal and a slow, inhibitory signal according to the LEGI model. Receptors that facilitate this process (-5[1])are divided into three families based on whether there are 0, 1, or 3 amino acids between their two N-terminal cysteines. Pro-inflammatory formyl peptides like fMLF mediate pattern recognition and this process. (-5[1])Leu·ko·tri·ene B4, complement protein 5a, and inter·leu·kin 8 are the main mediators of this process in neutrophils. HIV (*) enters T-cells and macrophages by hijacking two co-receptors that mediate this process, (-5[1])called CCR5 and CXCR4. Many immune cells use a gradient-sensing form of this process to target sites of foreign invasion. For 10 points, name this process in which a cell moves in response (10[2])to a chemical stimulus. (10[1])■END■ (10[3])