Delayed hypersensitivity to soluble antigens in mice. I. Analysis in vivo

Delayed hypersensitivity to a soluble protein has been analyzed in mice. Ear swelling, 24 h after injection of a test dose of antigen, has been used to monitor the response to a subcutaneous tail injection of egg albumin in complete Freund's adjuvant. Maximal 24 h ear swelling was observed 8 days after sensitization with either 50 or 100 microgram of antigen. These delayed reactions, which were characterized by mononuclear infiltrates, were relatively uncomplicated by Arthus reactions. The latter, antibody-mediated reactions were apparent at later times after immunization. More intense 24 hr reactions were elicited in C57BL/6 than BALB/c mice. Passive transfer of sensitivity has been accomplished with lymph node cells.