B10 cells promote pro-resolving macrophage function through direct cell-cell contact and IL-10 secretion in Raw 264.7...

Area of Science:

• Immunology
• Cell Biology

Background:

• Regulatory B cells (Breg), particularly IL-10-producing B10 cells, are crucial for immune regulation in inflammatory and infectious diseases.
• While B10 cell interaction with T cells is known, their influence on other immune cells like macrophages requires further investigation.

Purpose of the Study:

• To investigate the effect of B10 cells on macrophage phenotype and pro-resolving functions.
• To elucidate the roles of direct cell-cell contact and IL-10 secretion in B10-mediated macrophage modulation.

Main Methods:

• Co-culture of splenocyte-derived B10 cells (from wild-type or IL-10 knockout mice) with RAW 264.7 macrophages.
• Utilized trans-well inserts to differentiate between direct cell contact and soluble factor-mediated effects.
• Assessed macrophage polarization, programmed cell death 1 (PD-1) expression, specialized pro-resolving mediator (SPM) production (RvD5), and phagocytic activity.

Main Results:

• Direct co-culture of B10 cells with macrophages promoted a pro-resolving macrophage phenotype and increased PD-1 expression.
• These effects were reduced when cell-cell contact was prevented (trans-well) or when IL-10-deficient B cells were used.
• B10 cells enhanced macrophage release of RvD5 and improved phagocytic activity, with these functions being compromised without direct contact or IL-10.

Conclusions:

• B10 cells promote pro-resolving macrophage differentiation and function.
• Both direct cell-cell contact and IL-10 secretion by B10 cells are essential mechanisms for this macrophage modulation.