Increased vascular permeability, erythema, and leukocyte emigration induced in rabbit skin by streptococcal erythrogenic toxin type A.

A highly purified streptococcal erythrogenic toxin type-A (SET-A) caused increased vascular permeability, erythema, and leukocyte emigration when injected into the skin of rabbits. A blueing reaction indicating increased vascular permeability appeared at 1 h, reaching the highest intensity between 4 and 5 h, decreasing thereafter and completely disappearing at 12 h after toxin injection. The intensity of the increase in permeability was found to be dose dependent. The erythematous reaction began later and persisted longer than the blueing. The time course of leukocyte emigration was found roughly to parallel that of the blueing reaction. The skin reaction to SET-A in rabbits can be characterized as having an acute non-specific exudative inflammatory nature.