Related Experiment Video
Updated: Aug 14, 2026

Examination of Thymic Positive and Negative Selection by Flow Cytometry
Published on: October 8, 2012
Positive selection and lineage commitment during peripheral B-lymphocyte development
Shiv Pillai1, Annaiah Cariappa, Stewart T Moran
1Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA 02129, USA. pilai@helix.mgh.harvard.edu
Although it is appreciated that the antigen receptor on B cells is required for peripheral B-lymphocyte development and survival, it has been unclear whether this receptor interacts with self-antigens during development or if it signals constitutively in an antigen-independent fashion. The analysis of mutant mice in which antigen receptor signaling in B cells is either attenuated or enhanced has revealed the existence of a follicular versus marginal zone B-lymphocyte cell-fate decision. These analyses indicate that weak antigen receptor-derived signals favor marginal zone B-cell generation, and relatively strong signals favor the development of mature follicular B cells. Even stronger signals derived from the antigen receptor favor the generation of B1 B cells. This signal strength model for B-cell development supports the notion that self-antigens of varying affinity may mediate positive selection and lineage commitment. Direct evidence supporting such a view has been obtained from the analysis of antigen receptor knockin mice. Specific antigen receptors guide B cells to develop into specific lineages. Although Notch-2, nuclear factor-kappaBp50, and other genes are essential for marginal zone B-cell development, instructive signals delivered by the antigen receptor represent the primary force driving positive selection and lineage commitment in B lymphocytes.
Although it is appreciated that the antigen receptor on B cells is required for peripheral B-lymphocyte development and survival, it has been unclear whether this receptor interacts with self-antigens during development or if it signals constitutively in an antigen-independent fashion. The analysis of mutant mice in which antigen receptor signaling in B cells is either attenuated or enhanced has revealed the existence of a follicular versus marginal zone B-lymphocyte cell-fate decision. These analyses indicate that weak antigen receptor-derived signals favor marginal zone B-cell generation, and relatively strong signals favor the development of mature follicular B cells. Even stronger signals derived from the antigen receptor favor the generation of B1 B cells. This signal strength model for B-cell development supports the notion that self-antigens of varying affinity may mediate positive selection and lineage commitment. Direct evidence supporting such a view has been obtained from the analysis of antigen receptor knockin mice. Specific antigen receptors guide B cells to develop into specific lineages. Although Notch-2, nuclear factor-kappaBp50, and other genes are essential for marginal zone B-cell development, instructive signals delivered by the antigen receptor represent the primary force driving positive selection and lineage commitment in B lymphocytes.
Related Concept Videos
Lineage Commitment
Primary Lymphoid Organs
The red bone marrow is a soft, spongy tissue nestled in the interior of long bones such as the humerus and femur. It is the site...
Special Features of Adaptive Immunity
The primary cell types involved in adaptive immunity are T cells and B cells. Each type has a unique role in defending the body against pathogens. T cells are responsible for cell-mediated immunity. They identify and eliminate infected cells directly,...
Cells of the Adaptive Immune Response
T Cell Activation and Clonal Selection
Naive T cells that have not yet encountered an antigen express two primary CD...
B Cell Activation and Differentiation
When naive B cells encounter a specific antigen that can bind to the B cell receptor (BCR) on their surface, they undergo sensitization to respond to the antigen's presence. Sensitization begins with...

