Extracutaneous delayed hypersensitivity, particularly in the guinea-pig bladder.

In outbred guinea-pigs with a low level of hypersensitivity to hen egg albumin (HEA) at a time when circulating antibody was not detectable, unaggregated HEA in extracutaneous tissues was rapidly lost from the injection site and did not elicit lesions of delayed hypersensitivity. Aggregated HEA, however, was retained at the depot site and produced lesions in the bladders of similarly prepared guinea-pigs. In Hartley guinea-pigs with a high level of hypersensitivity, as measured by skin reactions, unaggregated HEA, though rapidly dissipated from depot sites, elicited lesions in the bladder. Aggregated HEA, though retained at injection sites, did not produced reactions of delayed hypersensitivity in kidney, testis and muscle. The inflammation of delayed hypersensitivity did not influence the disappearance rate of labelled HEA from the lesion, while the inflammation of an Arthus response was associated with retention of labelled antigen at the injection site.