Concanavalin A in vivo: induction of hemorrhagic skin lesions (Arthus-like reactions) in mice.

Concanavalin A injected into the skin of mice induced the formation of hemorrhagic Arthus-like lesions. No lesions resulted if concanavalin A was adsorbed with insoluble (a2)- macroglobulin or if mice were first treated with nitrogen mustard. The ability of concanavalin A, phytohemagglutinin, or pokeweed mitogen to induce skin lesions seemed to parallel their ability to precipitate serum proteins.