Frequency and avidity of specific antigen-binding cells in developing mice

Area of Science:

• Immunology
• Developmental Biology

Background:

• Antibody diversity is crucial for adaptive immunity.
• Understanding the developmental origins of antibody-producing cells is key to immune system development.

Purpose of the Study:

• To investigate the emergence and diversity of antigen-specific B cells during fetal and neonatal development in mice.
• To compare the repertoire of antibody specificities in fetal, neonatal, and adult mice.

Main Methods:

• Comparison of antigen binding by cells from fetal, neonatal, and adult mice.
• Analysis of antigen-specific cell numbers and binding avidities.
• Detection of cells binding 11 different antigens.

Main Results:

• Antigen-binding cells were detected in late-term fetuses (last 4 days before birth) in both liver and spleen.
• No restriction in the variety of antigen specificities or binding avidities was observed in fetal cells.
• Fetal liver cells disappeared within a day of birth, while splenic cells increased postnatally.

Conclusions:

• The fetal immune system is capable of generating a diverse range of antibody specificities.
• The spleen serves as a critical site for the postnatal expansion and maturation of antigen-specific B cells.
• This study provides insights into the developmental trajectory of antibody diversity from fetal to adult stages.