Related Experiment Video
Updated: Jul 19, 2026
11:48
Isolation Protocol of Mouse Monocyte-derived Dendritic Cells and Their Subsequent In Vitro Activation with Tumor Immune Complexes
Published on: May 31, 2018
Active MAC-1 (CD11b/CD18) on DCs inhibits full T-cell activation
Georg Varga1, Sandra Balkow, Martin K Wild
1Cell Biology, Department of Dermatology, University of Münster, Germany.
Blood
|September 28, 2006
Summary
Active beta2 integrins, specifically Mac-1 (CD11b/CD18) on antigen-presenting cells, inhibit T-cell activation. Blocking these integrins enhances antigen presentation, revealing a novel regulatory mechanism in immune responses.
Area of Science:
- Immunology
- Cell Biology
- Molecular Medicine
Background:
- Beta2 integrins mediate leukocyte migration and T-cell activation.
- The role of beta2 integrins on antigen-presenting cells (APCs) in antigen presentation is poorly understood.
- APCs, including dendritic cells (DCs) and macrophages, express beta2 integrins.
Purpose of the Study:
- To investigate the functional relevance of beta2 integrins on APCs for T-cell activation.
- To determine if beta2 integrins on APCs play a role in antigen presentation.
- To elucidate the specific beta2 integrin involved in regulating T-cell activation.
Main Methods:
- Utilized CD18-deficient mice lacking functional beta2 integrins.
- Assessed antigen presentation capacity of dendritic cells (DCs) from wild-type and knockout mice.
- Investigated the effect of pharmacologic activation and antibody blockade of beta2 integrins (Mac-1) on DCs and macrophages.
- Measured T-cell activation in response to antigen-presenting cells.
Main Results:
- Dendritic cells from CD18-deficient mice showed no defect in antigen presentation.
- Beta2 integrins on DCs are expressed in an inactive state and do not activate upon contact with T cells in vitro.
- Pharmacologic activation of beta2 integrins on DCs significantly reduced their T-cell activating capacity.
- Mac-1 (CD11b/CD18) blockade enhanced the antigen-presenting capacity of macrophages.
- Antibodies blocking CD18 and CD11b reversed the inhibitory effect of activated beta2 integrins on DCs.
Conclusions:
- Active CD11b/CD18 (Mac-1) on antigen-presenting cells directly inhibits T-cell activation.
- Beta2 integrins on APCs function as negative regulators of T-cell activation.
- Targeting Mac-1 could potentially enhance immune responses by improving antigen presentation.
Related Concept Videos
01:22T Cell Activation and Clonal Selection
T cells are integral to our adaptive immune system, recognizing and effectively responding to foreign antigens. T cell activation and clonal selection are pivotal in orchestrating this immune response. This article elucidates these mechanisms, detailing the roles of cluster of differentiation (CD) markers, major histocompatibility complex (MHC) molecules, costimulatory signals, and the process of clonal selection.
Naive T cells that have not yet encountered an antigen express two primary CD...
Naive T cells that have not yet encountered an antigen express two primary CD...
02:34Inhibition of Cdk Activity
The orderly progression of the cell cycle depends on the activation of Cdk protein by binding to its cyclin partner. However, the cell cycle must be restricted when undergoing abnormal changes. Most cancers correlate to the deregulated cell cycle, and since Cdks are a central component of the cell cycle, Cdk inhibitors are extensively studied to develop anticancer agents. For instance, cyclin D associates with several Cdks, such as Cdk 4/6, to form an active complex. The cyclin D-Cdk4/6 complex...