A new method of eliciting delayed hypersensitivity in the mouse abdominal cavity

A new method of determining delayed hypersensitivity quantitatively was investigated in mice. Mice were sensitized with 150 micrograms of ferritin and, 3 weeks later, antigen challenge was performed by implanting a sponge containing antigen in the abdominal cavity. Cells accumulated in the sponge markedly increased in number for 24-72 h after the challenge; mononuclear cells predominated by 48 h. When sensitized lymphocytes were transferred passively to a normal recipient, marked cell accumulation in the sponge was found 48 h after the challenge. Immunological specificity was confirmed in animals sensitized to antigen and receiving passive transfer of sensitized cells. Strain differences in this reaction were observed. Cortisone (20 mg/kg for 6 days before challenge) significantly decreased cell accumulation. Delayed hypersensitivity was also elicited in the ear of sensitized animals. Extracts of sponges removed from antigen-challenged mice had macrophage chemotactic activity.