A role for MHC class II antigen processing in B cell development.
For mature B cells, the encounter with foreign antigen results in the selective expansion of the cells and their differentiation into antibody secreting cells or memory B cells. The response of mature B cells to antigen requires not only antigen binding to and signaling through the B cell antigen receptor (BCR) but also the processing and presentation of the BCR bound antigen to helper T cells. Thus, in mature B cells, the ability to process and present antigen to helper T cells plays a critical role in determining the outcome of antigen encounter. In immature B cells, the binding of antigen results in negative selection of the B cell, inducing apoptosis, anergy or receptor editing. Negative selection of immature B cells requires antigen induced signaling through the BCR, analogous to the signaling function of the BCR in mature B cells. However, the role of class II antigen processing and presentation in immature B cells is less well understood. Current evidence indicates that the ability to process and present antigen bound to the BCR is a late acquisition of developing B cells, suggesting that during negative selection B cells may not present BCR bound antigen and interact with helper T cells. However, the expression of class II molecules is an early acquisition of B cells and recent evidence indicates that the expression of class II molecules early in development is required for the generation of long lived mature B cells. Here we review our current understanding of the processing and presentation of antigen by mature B cells and the role for antigen processing and class II expression during B cell development.
Sproul
T W
TW
Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, Evanston, IL 60208, USA.
Cheng
P C
PC
Dykstra
M L
ML
Pierce
S K
SK
D000818:Animals; D017951:Antigen Presentation / Q000276:immunology*; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology*; D002454:Cell Differentiation; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D006801:Humans
D000949:Histocompatibility Antigens Class II