Exosomes (top) containing antigen and MHC are shot out of B cells that meet partner T cells.

ROCHE/EMBO

T cells tell B cells to spit out exosomes loaded with T cell stimulants, report Aura Muntasell, Adam Berger, and Paul Roche (NIH, Bethesda, MD).

Exosomes are the membrane pockets that lie within larger vesicles called multivesicular bodies (MVBs). In B cells and other antigen-presenting cells, MVBs and exosomes house antigens in complex with the MHC class II molecules that present them to T cells. When an MVB fuses with the plasma membrane, MHC-antigen from the MVB membrane is displayed on the B cell surface, while the exosome allotment of MHC-antigen is sent out into the extracellular environment.

In the new study, the authors found that a B cell shot out twice as many exosomes when it met a T cell that recognized its antigen. In turn,...

The Rockefeller University Press
2007
The Rockefeller University Press
2007
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