T cell repertoires and competitive exclusion

Area of Science:

• Immunology
• Theoretical Ecology
• Mathematical Biology

Background:

• T-cell repertoire maintenance is crucial for adaptive immunity.
• Self-renewal is a proposed mechanism for T-cell homeostasis.
• T-cell activation involves interactions with antigen-presenting cells (APCs).

Purpose of the Study:

• To model T-cell activation dynamics and competition.
• To investigate the role of competition in T-cell repertoire maintenance.
• To understand the implications of competitive exclusion for T-cell responses.

Main Methods:

• Development of mathematical models for T-cell-APC interactions.
• Analysis of T-cell competition based on binding affinities.
• Application of the principle of competitive exclusion.

Main Results:

• Competition is inherent in T-cell binding to APCs.
• Only one T-cell clone survives competition per dominant peptide.
• This process enables affinity selection and regulates T-cell numbers within clones.
• Repertoire diversity is limited by the number of stimulating antigens.

Conclusions:

• Competitive exclusion shapes T-cell responses and repertoire diversity.
• Affinity selection determines dominant T-cell clones.
• T-cell competition regulates memory formation during persistent antigen exposure.
• The diversity of the T-cell repertoire may be influenced by self-antigen cross-reactivity.