Related Experiment Video
Updated: Aug 9, 2026
Advanced Imaging of Lung Homing Human Lymphocytes in an Experimental In Vivo Model of Allergic Inflammation Based on Light-sheet Microscopy
Published on: April 16, 2019
Conservation of structure and function between human and murine IL-16
1The Pulmonary Center, Boston University School of Medicine, MA 02118, USA.
Insights
Interleukin-16 (IL-16) shows high structural and functional similarity between mice and humans. The C-terminal region is crucial for IL-16
Area of Science:
- Immunology and Molecular Biology
- Cytokine Research
Background:
- Interleukin-16 (IL-16) is a proinflammatory cytokine involved in immune responses.
- Understanding conserved regions of IL-16 is key to identifying functional domains.
Purpose of the Study:
- To compare murine and human IL-16 homologs for conserved structures and functions.
- To identify critical regions of IL-16 responsible for its biological activity.
Main Methods:
- Cloning of murine IL-16 cDNA and comparison of amino acid sequences with human IL-16.
- Cross-species chemotaxis assays using murine and human cells.
- Synthesis of oligopeptides and anti-peptide antibodies targeting predicted IL-16 domains.
Main Results:
- High amino acid similarity between murine and human pro-IL-16, particularly in the C-terminal region.
- Cross-species chemotaxis stimulation observed with both murine and human IL-16.
- A C-terminal peptide inhibited IL-16 binding and chemoattractant activity.
Conclusions:
- Murine and human IL-16 share significant structural and functional conservation.
- The C-terminal domain of IL-16 is critical for its chemoattractant function.
- Conserved IL-16 receptor structures are suggested, with potential therapeutic applications for inhibitory peptides.
Abstract:
IL-16 is a proinflammatory cytokine that signals via CD4, inducing chemotactic and immunomodulatory responses of CD4+ lymphocytes, monocytes, and eosinophils. Comparative analysis of murine and human IL-16 homologs could reveal conserved structures that would help to identify key functional regions of these cytokines. To that end, we cloned the murine IL-16 cDNA and found a high degree of amino acid similarity comparing the predicted murine and human IL-16 precursor proteins (pro-IL-16). The highest similarity (82.1%) was found in the C-terminal region, which is cleaved from pro-IL-16 to yield biologically active IL-16. Chemotaxis experiments with IL-16 of murine and human origin, using murine splenocytes or human T lymphocytes as targets, showed cross-species stimulation of motility. Synthetic oligopeptides and anti-peptide Ab were produced, based on the sequences of three predicted hydrophilic domains of IL-16 potentially presented in exposed positions. None of these peptides had intrinsic IL-16 bioactivity, but one (corresponding to a hydrophilic C-terminal domain of IL-16) partially displaced binding of OKT4 mAb to human lymphocytes. This peptide, and its cognate Ab, also inhibited IL-16 chemoattractant activity for human and murine cells. These studies demonstrate a high degree of structural and functional similarity between human and murine IL-16 and suggest that amino acids in the C terminus are critical for its chemoattractant function. The data suggest cross-species conservation of IL-16 receptor structures as well. Inhibitory peptides may be useful in disease states where the proinflammatory functions of IL-16 are detrimental to the host.
