Structure and functional expression of a human interleukin-8 receptor

Area of Science:

• Immunology and Molecular Biology
• Cytokine Signaling Pathways

Background:

• Interleukin-8 (IL-8) is a key pro-inflammatory cytokine with diverse roles in immune cell chemotaxis and activation.
• IL-8 family members regulate neutrophil, monocyte, and T cell functions, impacting inflammatory responses.
• Understanding IL-8 signaling requires identifying its specific receptor and its molecular characteristics.

Purpose of the Study:

• To isolate and characterize the complementary DNA (cDNA) encoding the human neutrophil Interleukin-8 (IL-8) receptor.
• To determine the structural and functional properties of the IL-8 receptor.
• To investigate the IL-8 receptor's relationship to other G protein-coupled receptors.

Main Methods:

• Isolation of complementary DNA (cDNA) encoding the IL-8 receptor from human neutrophils.
• Amino acid sequence analysis to determine receptor family classification.
• Transfection of mammalian cells with the IL-8 receptor cDNA clone for functional assays.

Main Results:

• The IL-8 receptor cDNA was successfully isolated from human neutrophils.
• The deduced amino acid sequence reveals the receptor belongs to the superfamily of G protein-coupled receptors.
• The IL-8 receptor shares 29% sequence identity with receptors for fMet-Leu-Phe and C5a, suggesting a related subfamily.
• Transfected cells exhibited high-affinity IL-8 binding and specific calcium mobilization in response to IL-8.

Conclusions:

• The human IL-8 receptor is a G protein-coupled receptor that specifically binds IL-8 and mediates cellular signaling.
• The IL-8 receptor is likely part of a subfamily of G protein-coupled receptors involved in transducing signals for IL-8 family cytokines.
• This finding provides a molecular basis for understanding IL-8-mediated inflammatory processes.