Figure 3. Repeated application of PPD inhibits the development of diabetes in NOD mice.

The figure shows a Kaplan-Meier curve of the diabetes incidence for four groups of mice. DNCB-rep, PPD-rep and Water, refers to the groups of mice that were repeatedly exposed to DNCB, PPD or water every other week. PPD-induc refers to the group of mice that was only exposed to PPD in the fourth week of life. The NOD mice exposed to PPD repeatedly, displayed a cumulative diabetes incidence of 47%, in contrast to 93% of the water treated group (P = 0.004). The log-rank test for all the shown curves gives a significance of P = 0.008.