Abstract

Rong Wang, Huan Yang, Bo Xiao*, Xiaoxiao Duan and Kongliang Shu

To explore the mechanism of Tα146-162-iMDC in intervention of experimental autoimmune myasthenia gravis (EAMG) in terms of B cell activation through use of dendritic cells pulsed with Talpha146-162 in EAMG. Thirty-four healthy male C57BL/6J mice aged 6 to 8 weeks were randomized into model group (Group A), intervention group (Group B) and control group (Group C). Dendritic cells were cultured and loaded with Tα146-162 for intervention in Group B. From initial immunization to 90th day when the experimentation was terminated, the severity of EAMG was evaluated and the morbidity was calculated. Cbl-b mRNA was detected, and Syk and Lyn protein expression and phosphorylation were assessed. Anti-AChR IgM, total IgM, IgG1, IgG2b, and IgG2c were detected on 15d, 45d and 75d after initial immunization. The morbidity of EAMG in Group A was higher than in Group B (P<0.05), while no EAMG occurred in Group C. Cbl-b mRNA in the spleen and lymph nodes was statistically significantly higher in Group A than in Group C (P<0.01), while higher in Group B than in Group A (P<0.05), but lower than in Group C (P<0.05). Syk protein expression and phosphorylation in Group A was higher than in Group C (P<0.01), while lower in Group B than in Group A (P<0.05) and higher than in Group C (P<0.05). Lyn protein expression and phosphorylation in Group A was lower than in Group C (P<0.01), while higher in Group B than in Group A (P<0.05), and lower than in Group C (P<0.050). Anti-AChR antibody in Groups A and B was apparently higher than Group C (P<0.01) after immunization. There was no significant difference in anti-AChR IgM between Groups A and B at different time points (P>0.05). Anti-AChR IgG and IgG1 decreased in Group B compared to Group A at different time points (P<0.05, Day 15; P<0.05, Days 45 and 75, P<0.01). After secondary immunization, anti-AChR IgG2b decreased in Group B compared to Group A at different time points (P<0.05, Day 45; P<0.01, Day 75). No statistically significant difference was noted in Anti-AChR IgG2c between Groups A and B at different time points (P>0.05). Cblb suppresses secretion of subtypes of anti-AchR antibodies and B cell activation through negative regulation of B cell antigen receptor (BCR) signal pathway. Induction of B cell tolerance is a possible mechanism of intervention of Tα146-162-iMDC in EAMG.