B cell repertoire diversification precedes immunoglobulin receptor expression

Area of Science:

• Immunology
• Virology
• Molecular Biology

Background:

• The development of the B cell repertoire is crucial for adaptive immunity.
• Understanding B cell repertoire diversity and regulation is key to vaccine development and autoimmune disease research.

Purpose of the Study:

• To investigate the diversity of B cell repertoires in early precursors.
• To compare the antibody specificities of B cell precursors with those of mature B cells.

Main Methods:

• Generating monoclonal antibodies specific for influenza virus hemagglutinin (HA) from sIg- bone marrow B cell precursors.
• Stimulating cells in splenic fragment cultures.
• Analyzing antibody reactivity patterns (RP) to determine clonotype diversity.

Main Results:

• 68 monoclonal antibodies against influenza virus PR8 HA were generated.
• Reactivity pattern analysis identified at least 29 distinct clonotypes.
• The diversity of anti-HA antibody repertoires in sIg- bone marrow precursors was comparable to that of adult spleen cells.

Conclusions:

• Substantial diversification of the B cell repertoire occurs before surface immunoglobulin (sIg) expression.
• B cell repertoire diversification precedes interaction with in vivo regulatory mechanisms.
• Early B cell precursors possess a diverse repertoire of antigen-specific antibodies.