Cell-free passive transfer of delayed hypersensitivity to chemicals in guinea pigs

Delayed-type cutaneous reactivity to 2,4-dinitrochlorobenzene and 2,4-dinitrofluorobenzene in guinea pigs was transferred passively by fluids in which leukocytes from sensitive animals were incubated. Cells from peritoneal exudates, lymph nodes, and alveolar washings were employed. The cell-free transfer material was dialyzable, of small molecular size, and stable to 56 C for 30 min and -65 C for at least 9 weeks. It gave a ratio at 280 to 260 nm of 0.71. The relationships between temperature, pH, and cellular release of the transfer material were studied.