High-dimensional intravital microscopy reveals major changes in splenic immune system during postnatal development

Area of Science:

• Immunology
• Developmental Biology
• Cell Biology

Background:

• The spleen is crucial for immune surveillance, filtering blood-borne pathogens.
• Understanding spleen leukocyte development and spatial organization in vivo is limited.

Purpose of the Study:

• To characterize the dynamics of spleen immune development across the postnatal period using novel in vivo imaging.
• To compare splenic immune environments in newborns, infants, and adults.
• To investigate the impact of infection on spleen immune profiles.

Main Methods:

• Utilized a novel combination of antibodies and fluorophores for in vivo imaging of the spleen.
• Analyzed spleen immune cell populations and spatial organization across different developmental stages.
• Employed a malaria infection model to study immune responses.

Main Results:

• Described the dynamics of spleen immune development for the first time.
• Found similar lymphoid cell numbers and arrangements in adult and infant spleens.
• Revealed significant differences in the splenic immune environment of newborns compared to adults.
• Identified B cells as the most frequent immune cell subtype throughout development.
• Demonstrated how malaria infection alters spleen immune profiles in adults and infants.

Conclusions:

• The splenic immune environment undergoes significant changes during early development.
• In vivo imaging provides novel insights into spleen immune dynamics.
• Understanding these developmental changes and infection impacts is key to explaining varying infection severity.
• The developed imaging techniques offer valuable tools for biological research and intravital studies.