Clonal expansion under the microscope: studying lymphocyte activation and differentiation using live-cell imaging.

Area of Science:

• Immunology
• Cell Biology
• Biotechnology

Background:

• Clonal expansion of lymphocytes is fundamental to adaptive immunity.
• Heterogeneity in expansion levels and cell states within clones is increasingly recognized.
• In vivo studies of clonal expansion face challenges due to microenvironment complexity and tracking limitations.

Purpose of the Study:

• To describe the implementation of live-cell imaging in microwell arrays for studying lymphocyte clonal expansion.
• To highlight insights gained from these experimental systems.
• To outline future research directions in adaptive immunity.

Main Methods:

• Utilizing microfabricated microwell arrays for ex vivo culture of lymphocytes.
• Employing live-cell imaging for continuous, single-cell resolution tracking of thousands of expanding clones.
• Analyzing parameters such as cell number, proliferation, death, and differentiation state.
• Investigating intercellular interactions by co-culturing defined numbers of cells in microwells.

Main Results:

• Demonstrated the capability of microwell arrays to capture detailed clonal expansion dynamics.
• Revealed heterogeneity in cell proliferation, differentiation, and survival within expanding lymphocyte clones.
• Provided insights into stochastic and instructive mechanisms driving immune cell heterogeneity.
• Enabled the study of cell-cell interactions influencing immune responses.

Conclusions:

• Live-cell imaging in microwell arrays is a powerful methodology for dissecting lymphocyte clonal expansion.
• This approach enhances understanding of adaptive immunity heterogeneity and differentiation.
• Future research combining these methods with in vivo single-cell tracking will advance the field.