ICAM-1 mediated cell-cell adhesion exerts dual roles on human B cell differentiation and IgG production.

Intercellular adhesion molecule 1 (ICAM-1) plays prominent roles in mediating cell-cell adhesion which also facilitates B cell activation and differentiation with the help from CD4 T cells. Here, we have reported a unique phenomenon that increased ICAM-1 on purified human CD4 T cells upon anti-CD3/CD28 stimulation enhanced CD4 T-B cell adhesion whereas induced less B cell differentiation and IgG production. This was largely due to increased PD-1 expression on CD19 B cells after coculturing with hyperactivated CD4 T cells.