Induction of cell-mediated immunity in the mouse: circumstantial evidence for highly immunogenic antigen in the regional lymph nodes following skin painting with contact sensitizing agents.

This paper describes an investigation of why contact sensitizing agents cause strong cell-mediated immunity. Contact sensitivity was induced in mice by painting the skin with 4-ethoxymethylene-2-phenyloxazolone (oxazolone), and measured by the increase of ear thickness following challenge six days later. Reactivity was transferred by taking the regional lymph node cells from mice 18 h after immunization and injecting them into the footpads of recipients. This "18-h transfer" has several characteristics. As few as 2 X 10(4) cells were effective. The donor lymph node cells were best taken one to three days after immunization, were less effective on day 4 and virtually inactive by day 7. The recipients developed contact sensitivity when challenged on day 4, but lacked sensitivity when challenged on days 1 and 2 after transfer. The transferred cells were still active after treatment with anti-theta serum and complement. They also resisted 2,000 R in vitro, mitomycin, vinblastine, and inhibitors of protein synthesis such as emetine, cycloheximide and puromycin. The transfer was prevented by treatment with trypsin, freeze-thawing, and heating at 56 C. Plasma membranes were also immunogenic. The evidence suggests that the "18-h transfer" is a special type of active immunization, not due to ordinary free oxazolone, and that the agent is present within the lymph node in a free oxazolone, and that the agent is present within the lymph node in a specially immunogenic location or form.