Vaccination with IA-2 autoantigen can prevent late prediabetic nonobese diabetic mice from developing diabetes mellitus

DNA vaccine can be applied to deliver genes into cells to induce tolerance of some autoimmune diseases. This study aimed to evaluate the effect of DNA vaccine in preventing late prediabetic nonobese diabetic (NOD) mice from developing autoimmune diabetes mellitus. The cDNA of human IA2 was recombined to be used as the DNA vaccine. Plasmid IL-4/MCP-1 was co-administrated as the DNA adjuvant. 49 10-11-week-old NOD mice were grouped into four groups: the control group (n=10), IA-2 vaccine group (n=17), IL-4/MCP-1 vaccine group (n=8) and IA-2 plus IL-4/MCP-1 vaccine group (n=14) by intramuscularly injected with 50 μg plasmid in each quadriceps muscle. Glucose levels in the groups were detected every 1-2 weeks. Insulitis was evaluated with hematoxylin and eosin-stained pancreatic sections. CD4(+) CD25(+)and CD8(+) T lymphocytes were measured with flow cytometry. The results showed that in 10-11-week-old female NOD mice, vaccination with IA2 or in combination with IL-4/MCP-1 delayed the onset of disease compared with the control group (p<0.05). Our results suggest that the DNA vaccine IA2 can prevent NOD mouse from developing autoimmune diabetes and this efficiency is related to the immune status of the recipients. Our findings offer new insights into the immune system and suggest novel methods of type 1 diabetes prevention.