IgM+IgD+CD27+ B cells from peripheral blood have been described as circulating marginal zone B cells. It is still unknown when and where these cells develop. These IgM+IgD +CD27+ B cells exhibit somatic hypermutations (SHMs) in their B cell receptors, but the exact nature of the signals leading to induction of these SHMs remains elusive. Here, we show that IgM+IgD +CD27+ B cells carrying SHMs are observed during human fetal development. To examine the role of T cells in human IgM +IgD+CD27+ cell development we used an in vivo model in which Rag2-/-γc-/- mice were repopulated with human hematopoietic stem cells. Using Rag2 -/-γc-/- mice on a Nude background, we demonstrated that development and induction of SHMs of human IgM +IgD+CD27+ B cells can occur in a T cell - independent manner.

, , , , , , , , , , , , , , , , , , , , , , , , , , , , , , ,
doi.org/10.1084/jem.20070447, hdl.handle.net/1765/15212
The Journal of Experimental Medicine
Erasmus MC: University Medical Center Rotterdam

Scheeren, F., Nagasawa, M., Weijer, K., Cupedo, T., Kirberg, J., Legrand, N., & Spits, H. (2008). T cell-independent development and induction of somatic hypermutation in human IgM+IgD+CD27+ B cells. The Journal of Experimental Medicine, 205(9), 2033–2042. doi:10.1084/jem.20070447