CIA-derived PMN-MDSCs’ effects on TNF-𝛂 expression,
proliferation and apoptosis of B cells
To verify the regulatory role of PMN-MDSCs on B cells, we cocultured B
cells with PMN-MDSCs, finding that
TNF-𝛂+B cells (Fig. 4A) and Ki67+ B cells (Fig. 4B)
increased in the presence of PMN-MDSCs. And the enhancing effects
increased with increasing ratio of PMN-MDSCs to B cells (Fig. 4E, 4F).
The supernatants of the coculture medium had higher IgG (Fig. 4C) and
TNF-𝛂
(Fig. 4D) concentration compared with B cells alone. In addition,
PMN-MDSCs decreased B cells’ apoptosis in vitro (Fig. 4G, 4H).
The coculture assay demonstrated that PMN-MDSCs played supporting role
to B cells. We further explored the difference of CIA and DBA/1J mice
derived PMN-MDSCs’ effects on B cells, finding that PMN-MDSCs derived
from DBA/1J mice had weaker or even no modulatory ability compared to
the counterparts of CIA mice (Fig. 4I-4K).