Alpha-2-macroglobulin-kallikrein complex: a temperature-sensitive mediator in contact-system-induced inflammation with a potential role in late and delayed hypersensitivity responses.

Maximal complexing of alpha 2-macroglobulin (alpha 2M) and kallikrein (KK) occurs at a temperature of 22-24 rather than at 37 degrees C. The protease expressivity of the complex is also maximal at 22-24 degrees C. alpha 2M-KK complex, sustained permeability changes in guinea pig skin. These findings suggest that the complex, rather than free KK, could play a role in the kinin release reported in some late-phase reactions, some instances of delayed-type hypersensitivity and some cold-induced reactions.