| Objective To investigate whether CD40 DNA vaccine could inhibit the immune response and slow the disease progression of Sjogren’s syndrome in non-obese diabetic (NOD) mice.Methods Twenty-one 8-weeks-old female NOD mice were randomly divided into 4 groups, with vaccine group (n=6), vector group (n=6), normal saline (NS) (n=6), Sjogren’s syndrome model (n=3). Plasmid DNA or vector or NS were injected 4 weeks in related groups. At wk 0, we killed 3 mice in Sjogren’s syndrome group. We killed 3 mice in each groups at wk 6 and wk 10. The spleen and salivary glands were harvested. The histopathological change of salivary gland was examined by H&E staining. The percentages of CD3+T cells, CD4+T cells, CD8+T cells, CD19+B cells and plasma cells in spleen were analyzed by flow-cytometry. The level of CD40, TNF-a and IL-1 (3 mRNA in salivary gland were evaluated by using Real-time PCR.Results (1) At week 6, among three groups, the histopatholgical change of focal lymphocytic infiltrates was ameliorated in CD40 vaccine group.(2) At week 6, the percentages of CD3+T cells in the spleen were decreased significantly in CD40 vaccine group (26.70±3.55 vs 36.37±0.89, P=0.011),and the percentages in vaccine group is decrased compared to vector and NS group (P=0.013; P=0.022). The percentages of CD4+T cells were significantly different among three groups (F=8.614, P=0.017) and the percentages in vaccine group is decrased compared to vector and NS group (P=0.009; P=0.015). The percentages of CD4+ T cells, CD8+ T cells, CD19+ B cells were significantly decreased in CD40 vaccine group compared to baseline (16.44±2.76 vs 21.96±1.08, P=0.032; 6.91±0.47 vs 9.32±0.20, P=0.001; 28.28±0.82, P=0.003,respectively). In vector group, the percentages of CD19+ B cells were also significantly decreased (31.48±0.75, P=0.018). The percentages of CD138+ plasma cells in CD19+ T cells were significantly different among three groups (F=9.736, P=0.013) and the percentages in vaccine and vector group is decrased compared to NS group (P=0.007; P=0.012). At week 10, the percentages of CD3+ T cells were significantly increased in all three groups compared to Sjogren’s syndrome group (40.37±8.42, P=0.004; 38.95±11.31, P=0.032; 38.49±10.21, P=0.046;respectively). In vector and NS group, the percentages of CD4+ T cells were increased (24.19±0.86, P=0.049; 24.34±0.58, P=0.028). The percentages of CD8+ T cells were significantly increased compared to baseline (10.46±0.63, P=0.041).(3) At week 6, the expression of CD40 mRNA was significantly decreased compared to vector group (0.51±0.31 vs 1.56±0.53, P=0.042). At week 10, the expression of TNF-α was significantly decreased (0.41±0.25 vs 0.98±0.16, P=0.03).Conclusion CD40 DNA vaccine can ameliorate the pathologic change in NOD mice with Sjogren’s syndrome, decrease the percentages of T cells and B cells in the spleen and inhibit the autoimmune responses, downregulate the expression of CD40 and TNF-α and reduce the inflammation. |
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