Administration of anti‐type II collagen antibody sustains footpad swelling of mice caused by a delayed‐type hypersensitivity reaction and induces severe arthritis
Delayed‐type hypersensitivity (DTH) is an immune reaction induced by antigen. In the mice footpads at which DTH is elicited, transient swellings which usually peaks at 24–48 h after the antigen challenge are observed. We found that the footpad swellings of mice are sustained for at least 7 days after the antigen challenge if the mice were injected with anti‐type II collagen monoclonal antibody (anti‐CII MoAb) before the antigen challenge. A histological section of the swelled hindpaw revealed that severe joint inflammation and bone destruction was induced. These features were not observed in the footpads of the DTH‐induced mice. Analysis of the inflammatory reaction induced by both the DTH and the anti‐CII MoAb injection, here named as DTH arthritis, revealed the following: (1) DTH arthritis is elicited in an antigen‐specific manner; and (2) the development of DTH arthritis is mediated by antigen‐specific T cells, especially CD4+ T cells.