Related Experiment Video
Updated: Jul 13, 2026
12:09
Use of Single Chain MHC Technology to Investigate Co-agonism in Human CD8+ T Cell Activation
Published on: February 28, 2019
Human CD18 is the functional receptor for Aggregatibacter actinomycetemcomitans leukotoxin
T Dileepan1, S C Kachlany, N V Balashova
1Department of Veterinary and Biomedical Sciences, University of Minnesota, 1971 Commonwealth Avenue, St. Paul, MN 55108, USA.
Infection and Immunity
|July 20, 2007
Summary
Aggregatibacter actinomycetemcomitans leukotoxin (LtxA) targets immune cells. Researchers identified human CD18 as the specific receptor for LtxA, revealing critical domains for LtxA
Area of Science:
- Microbiology
- Immunology
- Molecular Biology
Background:
- Aggregatibacter actinomycetemcomitans causes aggressive periodontitis and endocarditis.
- Leukotoxin (LtxA) is a key virulence factor targeting immune cells.
- Lymphocyte function-associated antigen 1 (LFA-1) is the suspected LtxA receptor.
Purpose of the Study:
- Identify the specific subunit of LFA-1 that functions as the LtxA receptor.
- Determine the regions of the receptor critical for LtxA binding and activity.
Main Methods:
- Utilized chimeric beta2-integrins expressed in LtxA-resistant cells.
- Investigated LtxA binding and biological effects on engineered cells.
Main Results:
- Demonstrated that human CD18 is the functional receptor for LtxA.
- Identified specific extracellular domains (integrin-epidermal growth factor-like domains 2, 3, and 4) of CD18 as critical for LtxA interaction.
- Showed these domains confer species-specific susceptibility to LtxA.
Conclusions:
- Human CD18 is the primary receptor for Aggregatibacter actinomycetemcomitans leukotoxin.
- Specific extracellular domains of CD18 are essential for LtxA's cytotoxic effects.
- Findings advance understanding of bacterial pathogenesis and host-pathogen interactions.
Related Concept Videos
01:24Adherens Junctions
Strong contact points between adjacent cells anchor them to each other, forming tissues. Such anchoring junctions are of two types – adherens junctions and desmosomes. Adherens junctions are abundant in tissues such as epithelium and endothelium, forming a continuous zone of adhesion called the adhesion belt. In other tissues, such as heart muscle, they appear as clusters, linking the cells to produce coordinated heart muscle contraction.
Adherens Junctions are Dynamic
The endothelial cells...
Adherens Junctions are Dynamic
The endothelial cells...
01:31Immunoglobulin-like Cell Adhesion Molecules
Immunoglobulin-like cell adhesion molecules or Ig-CAMs are a versatile group of cell surface glycoproteins belonging to the immunoglobulin protein superfamily. Ig-CAMs possess the characteristic immunoglobulin protein domains and other domains such as the fibronectin type III domain. The Ig domains are glycosylated to varying degrees in different Ig-CAMs.
Ig-CAMs exhibit either homophilic binding (to other Ig-CAMs) or heterophilic binding (to other ligands such as integrins). While most Ig-CAMs...
Ig-CAMs exhibit either homophilic binding (to other Ig-CAMs) or heterophilic binding (to other ligands such as integrins). While most Ig-CAMs...
01:25Selectins
Cell adhesion is an essential aspect of multicellularity. While stable cell interactions usually occur between cells of the same type, transient cell interactions occur between cells of different tissue types, such as between neutrophils and endothelial cells. Selectins are one class of cell adhesion molecules (CAMs) that bind carbohydrate ligands to form transient cell adhesion. They are rod-like proteins with a long extracellular part of variable length ending with the lectin domain, which...
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...
01:13Actin Polymerization and Cell Motility
Actin is a family of globular proteins that are highly abundant in eukaryotic cells. It makes up approximately 1-5% of total cell protein concentration. Actin monomers polymerize to form a complex network of polarized filaments, the actin cytoskeleton, that plays a crucial role in many cellular processes, including cell motility, division, endocytosis, and metastasis of cancer cells.
Actin cytoskeleton dynamics can produce pushing, pulling, and resistance forces that help the cell to migrate.
Actin cytoskeleton dynamics can produce pushing, pulling, and resistance forces that help the cell to migrate.
01:26Antigens Involved in Adaptive Immunity
An antigen is any substance the immune system identifies as foreign and potentially harmful to the body, prompting an immune response. Antigens have two functional properties: immunogenicity and reactivity. Immunogenicity is the ability of an antigen to stimulate a specific immune response. At the same time, reactivity describes the antigen's ability to react with the cells and antibodies produced in response to it.
Complete Antigens
Complete antigens possess both immunogenicity and reactivity.
Complete Antigens
Complete antigens possess both immunogenicity and reactivity.