Leukotoxins of gram-negative bacteria.

Leukotoxins are a group of exotoxins that produce their primary toxic effects against leukocytes, especially polymorphonuclear cells (PMNs). Leukotoxins include a variety of chemicals ranging from 9,10-epoxy 12-octadecenoate, a fatty acid derivative secreted by leukocytes themselves, to proteins such as RTX (repeats in toxin). This review focuses on leukotoxins of three species of gram-negative bacteria, Mannheimia (Pasteurella) haemolytica, Actinobacillus actinomycetemcomitans, and Fusobacterium necrophorum.