Immune and allergic reactions to diphtheria toxin and toxoid in guinea-pigs

Abstract

Guinea-pigs immunized with alum-precipitated diphtheria toxoid (APT) become hypersensitive to diphtheria toxin and toxid. This hypersensitivity is probably due to a mixture of immediate (Arthus-type) reactions and delayed (tuberculin-type) reactions, the former increasing as the level of circulating precipitating antitoxin rose and tending to mask the latter. In a hyperimmune guinea-pig the residual damage following the intradermal injection of toxin is due, at least in part, to hypersensitivity to toxin; toxicity probably contributes relatively little to the extent of the lesion in animals with a high titre of antitoxin.The technical difficulties of proving the presence of a delayed allergic reaction in animals with an early allergic reaction are discussed.I am grateful to Dr C. G. Pope, who has been closely associated with this work, not only for providing highly purified materials, but also for his advice.