Mucosal tissue cues shape B cell memory through the IgA BCR

Area of Science:

• Immunology
• Microbiology
• Cell Biology

Background:

• B cells differentiate into plasma cells (PCs) and memory B cells (MBCs) to fight infections.
• B cell receptor (BCR) affinity influences B cell fate, but factors during actual infections are unclear.

Purpose of the Study:

• To investigate the factors regulating B cell fate decisions during respiratory and gastrointestinal infections in mice.
• To understand how tissue-specific cues influence the selection of MBCs versus PCs.

Main Methods:

• Utilized mouse models of respiratory and gastrointestinal infections.
• Analyzed B cell selection processes across different barrier tissues (lung and gut).
• Investigated the role of BCR isotype usage and affinity maturation in B cell fate.

Main Results:

• B cell selection varied by tissue: lungs favored MBCs, while the gut favored PCs, even with the same pathogen.
• This divergence was linked to differential BCR isotype usage, not affinity maturation.
• Gut environment, rich in TGF-β and promoting IgA class-switching, skewed selection toward PCs, modulated by the IgA cytosolic tail.

Conclusions:

• Mucosal B cell selection integrates tissue-specific cues through BCR isotype usage.
• Findings have implications for developing effective nasal and oral vaccines.
• Understanding tissue-specific B cell responses is crucial for optimizing vaccine strategies.