pDCs promote B cell class-switching and antibody production
Correlation analysis between the frequency of peripheral pDCs and clinical parameters in pSS patients showed that the percentage of pDCs was negatively correlated with serum IgG, IgA, and anti-SSA autoantibody levels (Fig S2a-i, Fig 3d). We, therefore, established the pDC/B cells co-culture system to explore the potential role of pDC in promoting B cell responses and antibody production in pSS patients.
We found that resting or TLR-7-activated pDCs were able to efficiently promote the proliferation, activation, and differentiation into plasmablast/plasma cell of B cells (Fig 4a-e, Fig S3a-e). Also, we explored the effects of pDCs on antibody production and found that even resting pDCs could promote IgG, and IgA production by B cells (Fig 4f). However, there was no difference between HC and pSS-derived pDCs. Similarly, no difference was found in the effects of HC or pSS derived pDCs on naive or memory B cells (Fig S4).