Fig. 1.

Diabetes incidence and insulitis severity in non-obese diabetic (NOD) mice injected with DNA. Female mice (4 weeks old) were inoculated intramuscularly (i.m.) with three 100-μg doses of DNA-HSP65 (pVAX-HSP65) or DNAv (pVAX) at 15-day intervals. Controls received identical injections of phosphate-buffered saline (PBS). Each group consisted of 10 mice. (a) Serum glucose levels were assayed weekly until mice reached the age of 28 weeks. (b) Pancreata from 28-week-old NOD mice were removed for histological analysis. To quantify islet infiltration, at least 20 islets from three sections per pancreas were examined in a blinded fashion. The degree of insulitis was evaluated using a semiquantitative scale: 0 = islet devoid of insulitis; 1 = peri-insulitis or insulitis occupying up to 10% of the islets; 2 = insulitis involving 10–50% of the islets; 3 = insulitis involving more than 80% of the islets; and 4 = destructive insulitis.