Developmental changes in the rules for B cell selection

Area of Science:

• Immunology
• Developmental Biology
• Molecular Biology

Background:

• The autoimmune checkpoint normally eliminates self-reactive B cells.
• B-1 cells are an exception, being self-reactive and positively selected.
• Mechanisms of B-1 cell tolerance escape remain largely unknown.

Purpose of the Study:

• To explore developmental changes in B cell selection constraints using B-1 cells.
• To understand how B-1 cells escape central tolerance during early life.
• To investigate the role of Lin28b in self-reactive B cell development.

Main Methods:

• Analysis of B-1 cell development during fetal and neonatal life.
• Investigation of the molecular program governing B-1 cell output.
• Exploration of developmental constraints on B cell selection.

Main Results:

• B-1 cells exhibit a restricted developmental window for self-reactive B cell output.
• The RNA binding protein Lin28b is central to the molecular program licensing B-1 cell development.
• Early life B cell tolerance rules differ significantly from adult tolerance.

Conclusions:

• Lin28b facilitates the escape of self-reactive B-1 cells from central tolerance.
• Developmental stage critically influences B cell selection and self-tolerance.
• A model is proposed linking early life tolerance, microbial mutualism, and neonatal immune imprinting.