Related Experiment Video
Updated: May 21, 2026

Isolation Protocol of Mouse Monocyte-derived Dendritic Cells and Their Subsequent In Vitro Activation with Tumor Immune Complexes
Published on: May 31, 2018
Membrane interleukin-18 revisits membrane IL-1α in T-helper type 1 responses
1University of Colorado Denver, Division of Infectious Diseases, B168, 12700 East 19th Ave., Auroia, CO 80045, USA. cdinarello@mac.com
Insights
Interleukin-18 (IL-18) functions as a membrane protein on macrophages, inducing IFN-γ from NK cells upon LPS stimulation. This finding highlights IL-18
Area of Science:
- Immunology
- Cell Biology
- Molecular Biology
Background:
- Cytokine-receptor interactions are typically studied using soluble forms.
- Membrane-bound cytokines can mediate biological activity through cell-cell contact.
- Interleukin-18 (IL-18) is a key cytokine for inducing T-helper 1 (Th1) responses.
Purpose of the Study:
- To investigate the membrane-bound form of Interleukin-18 (IL-18).
- To determine the biological activity of membrane-bound IL-18 in human macrophages.
- To elucidate the mechanism of IL-18-mediated immune cell activation.
Main Methods:
- Utilized M-CSF-differentiated human macrophages.
- Investigated IL-18 expression and localization on the cell membrane.
- Assessed the induction of Interferon-gamma (IFN-γ) from Natural Killer (NK) cells upon lipopolysaccharide (LPS) stimulation.
- Examined the role of caspase-1 in the observed IL-18 activity.
Main Results:
- Interleukin-18 (IL-18) was identified as an integral membrane protein on M-CSF-differentiated human macrophages.
- LPS stimulation led to IL-18-mediated induction of Interferon-gamma (IFN-γ) from NK cells.
- This induction was dependent on caspase-1 activity.
Conclusions:
- Membrane-bound IL-18 plays a significant role in immune cell communication.
- The findings have substantial immunological and inflammatory implications, particularly for Th1-mediated immunity.
- Caspase-1 is crucial for the function of membrane-bound IL-18 in inducing IFN-γ.
Abstract:
Although all structural studies on cytokine-cytokine receptor interactions are based on a crystallized cytokine binding to its specific receptor, there is no dearth of evidence that membrane-embedded cytokines are biologically active by virtue of cell-cell contact. Clearly the orientation of the membrane cytokine is such that it allows binding to the receptor, as takes place with the soluble form of the cytokine. In this issue, Bellora et al. [Eur. J. Immunol. 2012. 42: 1618-1626] report that interleukin-18 (IL-18) exists as an integral membrane protein on M-CSF-differentiated human macrophages and that upon LPS stimulation, IL-18 induces IFN-γ from NK cells in a caspase-1-dependent fashion. The immunological and inflammatory implications for this finding are considerable because of the role of IL-18 as the primary IFN-γ inducing cytokine in promoting Th1 responses.
Related Concept Videos
T Cell Types and Functions
Th1 cells stimulate dendritic cells to express necessary co-stimulatory molecules on their surfaces for...
Cell-mediated Immune Responses
Immune Response Against Viral Pathogens
NK Cells
NK cells are a crucial part of our innate immune system, acting as the first line of defense against viral infections. These cells can recognize and kill infected cells without prior exposure to the virus, effectively slowing down the spread of infection. Additionally, NK cells produce proinflammatory...

