Contact and delayed hypersensitivity in the mouse. II. The role of different cell populations.

Mice sensitized to oxazolone show contact sensitivity which can be assessed by painting oxazolone on the ear and measuring the increase in ear thickness at 24 hours. Contact sensitivity can be transferred passively by peritoneal exudate, lymph node and bone marrow cells. When CBA mice are challenged immediately after transfer, at a 3:1 donor recipient ratio, the peritoneal exudate cells give bigger transferred reactions than lymph node cells. The converse is true on challenge at 6 days after transfer, at which time the lymph node cells give bigger transferred reactions than the peritoneal exudate cells. These results suggest that different types or functional states of cells are involved in these two types of transfer. The possibility that the successful transfer with delayed challenge by lymph node cells was due to active sensitization by antigen transferred with the cells, was made unlikely by passive transfer into `tolerant' recipients. Mice first show contact sensitivity when challenged at 3 days (about 72 hours) after sensitization. The lymph nodes develop the ability to transfer contact sensitivity with delayed challenge at the same time but the bone marrow only acquires this activity at 5 days.