Discordant Restoration of TCR Expression and Function by CD247 Somatic Reversions

Area of Science:

• Immunology
• Molecular Biology
• Genetics

Background:

• The CD247 chain is crucial for T-cell receptor (TCR) function and T cell development.
• CD247-deficient patients exhibit severe immunodeficiency, with limited clinical improvement from somatic revertant T cells.

Purpose of the Study:

• To compare the functional capacity of somatic revertant variants of CD247 germline changes to restore TCR expression and signaling.
• Investigate the differing impacts of specific CD247 variants (p.M1T and p.Q70X) on T cell function.

Main Methods:

• Utilized human and mouse T cell lines (MA5.8, PM1T, ZKO) with CD247 deficiency.
• Introduced wild-type (WT) and various CD247 somatic variants (p.Q70L/W/Y) via nucleofection or transduction.

Main Results:

• Mouse T cell models (MA5.8) did not accurately reflect human CD247 deficiency responses.
• In human cells, all tested CD247 somatic variants restored TCR expression to varying degrees.
• While TCR expression was restored, TCR-induced activation events and ZAP70 phosphorylation were impaired, indicating incomplete functional rescue.

Conclusions:

• Somatic reversions in CD247 germline changes show a variable ability to restore TCR expression versus function.
• Findings illuminate CD247's role in TCR expression and function during human T cell development.
• Implications for understanding immunodeficiencies and the consequences of CD247 somatic mosaicism.