Isolation of cDNA clones encoding the 20K T3 glycoprotein of human T-cell receptor complex

Area of Science:

• Immunology
• Molecular Biology
• Genetics

Background:

• The T3/T-cell receptor (TCR) complex is crucial for adaptive immunity.
• Understanding the components of the T3/TCR complex is essential for deciphering T-cell activation pathways.

Purpose of the Study:

• To determine the complete amino acid sequence of the T3 delta-chain, a polypeptide within the human T3/TCR complex.
• To analyze the structural domains and potential functional implications of the T3 delta-chain sequence.

Main Methods:

• Deduction of amino acid sequence from cDNA clones derived from HPB-ALL cells and a human T-cell clone.
• Bioinformatic analysis of the deduced 171-amino acid sequence.

Main Results:

• The T3 delta-chain sequence includes a signal peptide, extracellular, transmembrane, and intracellular domains.
• No sequence homology was found between the T3 delta-chain and the T-cell receptor/immunoglobulin/MHC multi-gene family.
• The T3 delta-chain is encoded by a single-copy gene with expression restricted to T lymphocytes in humans and mice.

Conclusions:

• The T3 delta-chain possesses a unique structure distinct from other immune gene families.
• The restricted expression pattern suggests a specific role for the T3 delta-chain in T-lymphocyte function.
• Further research can explore the functional significance of the T3 delta-chain's distinct domains.