The effects of
KB-2413 on four types of
allergic reactions classified by Coombs and Gell were investigated.
KB-2413 inhibited homologous passive cutaneous anaphylaxis and passive anaphylactic bronchoconstriction in guinea pigs mediated by
IgE-like antibody, and ED50 values were 0.0017 mg/kg, p.o., and 0.022 mg/kg, p.o., respectively.
KB-2413 also inhibited
IgG-mediated anaphylactic bronchoconstriction in guinea pigs actively sensitized with egg
albumin. Both
complement-dependent immune
hemolysis and
complement-independent hypotonic
hemolysis were inhibited by
KB-2413 in a concentration-dependent manner.
KB-2413 had no effect on the Forssman systemic reaction. The passive
Arthus reaction in guinea pigs sensitized with anti-egg
albumin rabbit serum was unaffected by
KB-2413. However, the early stage of the active
Arthus reaction in rabbits sensitized with egg
albumin was inhibited.
KB-2413 had an inhibitory effect on the efferent phase of delayed-type
hypersensitivity induced by
picryl chloride (PC-DTH) in mice. On the other hand, the afferent phase of PC-DTH in mice was unaffected. These results suggest that
KB-2413 strongly suppresses type I
allergic reactions, and it slightly suppresses type II, III and IV
allergic reactions.