Heterogeneous differentiation patterns of individual CD8+ T cells

Area of Science:

• Immunology
• Cell Biology
• T cell biology

Background:

• CD8(+) T cell responses are crucial for adaptive immunity.
• These responses typically exhibit reproducible expansion and contraction patterns post-infection.
• This reproducibility has been assumed to stem from uniform individual cell behavior.

Purpose of the Study:

• To investigate the heterogeneity of individual CD8(+) T cell responses.
• To determine if individual T cells behave uniformly during clonal expansion and differentiation.
• To understand the contribution of individual T cells to both primary and recall immune protection.

Main Methods:

• In vivo lineage tracing of individual mouse CD8(+) T cells.
• Tracking the progeny of T cells with identical T cell receptors.
• Analyzing the differential contribution of T cell progeny to immune memory.

Main Results:

• Individual CD8(+) T cells, even with identical T cell receptors, exhibit heterogeneous clonal expansion and differentiation.
• The progeny of single naïve T cells contribute differently to short-term and long-term immunity.
• This heterogeneity was observed despite the overall reproducible population-level response.

Conclusions:

• CD8(+) T cell heterogeneity is intrinsic and not solely driven by asymmetric division.
• Reproducibility of CD8(+) T cell responses is an emergent property of population averaging.
• Individual T cell variation significantly influences the development of immunological memory and protection.