LYMPHOCYTE VACCINATION PREVENTS SPONTANEOUS DIABETES IN THE NONOBESE DIABETIC MOUSE

The aim of this study was to investigate whether lymphocyte vaccinatio n can prevent diabetes occurring in the non-obese diabetic (NOD) mouse , an animal model of human insulin-dependent diabetes mellitus (IDDM). The lymphocyte vaccine was composed of lymphocytes isolated from the spleens of diabetic NOD mice, activated in vitro using concanavalin A (Con A) and rendered immunogenic using glutaraldehyde treatment. These cells were used to vaccinate mice at 6 weeks with boosters at weeks 1 0, 14 and 18. The animals were then monitored for signs of diabetes un til week 30. Twenty-eight NOD mice (11 male, 17 female) were T-lymphoc yte vaccinated while 35 littermates (14 male, 21 female) were sham vac cinated with the vaccine carrier, as control mice. The percentage of m ice remaining non-diabetic was 50% in the T-lymphocyte vaccinated grou p compared with 20% in control mice (P < 0.05). When the results were divided according to sex of the mouse the percentage of female NOD mic e remaining non-diabetic was 47.1% in the T-lymphocyte-vaccinated grou p compared to only 9.4% in the controls (P<0.01), while in the males t here was no significant difference between the groups. These results s uggest that T-lymphocyte vaccination can prevent diabetes in NOD mice and that it has its greatest effect in females. The therapy is apparen tly safe and its efficacy indicates that it may be of value in prediab etes in man.