Related Experiment Video

Updated: Aug 11, 2026

Visualization of Bacterial Toxin Induced Responses Using Live Cell Fluorescence Microscopy
14:29

Visualization of Bacterial Toxin Induced Responses Using Live Cell Fluorescence Microscopy

Published on: October 1, 2012

Effect on polymorphonuclear cell function of a human-specific cytotoxin, intermedilysin, expressed by Streptococcus

M G Macey1, R A Whiley, L Miller

  • 1Department of Haematology, Barts and the London NHS Trust, United Kingdom. macey.marion@royalhos-tr.nthames.nhs.uk

Infection and Immunity
|September 13, 2001
PubMed

Insights

Intermedilysin (ILY) from Streptococcus intermedius impacts polymorphonuclear cell (PMN) function. While decreasing intact PMNs, ILY enhances PMN calcium, CD11b expression, and phagocytosis, potentially influencing deep-seated abscesses.

Area of Science:

  • Microbiology
  • Immunology
  • Cell Biology

Background:

  • Streptococcus intermedius is a commensal oral bacterium and an opportunistic pathogen.
  • Intermedilysin (ILY) is a cytolysin produced by S. intermedius, specific for human cells.
  • Polymorphonuclear cells (PMNs) are crucial for innate immunity.

Purpose of the Study:

  • To investigate the effects of purified intermedilysin (ILY) on polymorphonuclear cell (PMN) function.
  • To understand the role of ILY in the context of bacterial infections and host immune response.

Main Methods:

  • Purified intermedilysin (ILY) was used to treat human PMNs.
  • Assays included measurement of intact PMNs, intracellular calcium, CD11b expression, metabolic burst, and phagocytosis of Staphylococcus aureus.
  • Comparison was made between active and heat-inactivated ILY.

Main Results:

  • Active ILY significantly reduced the number of intact PMNs at 40 ng/microl after 60 minutes.
  • Active ILY did not exhibit chemotaxis but increased intracellular calcium levels in PMNs.
  • Active ILY enhanced PMN metabolic burst and phagocytosis of Staphylococcus aureus.

Conclusions:

  • Intermedilysin (ILY) modulates PMN function, impacting both cell viability and activity.
  • These findings suggest a complex role for ILY in S. intermedius infections, potentially contributing to abscess formation.
  • ILY's effects on PMNs warrant further investigation for understanding its pathogenicity.

More Related Videos

Implementation of a Permeable Membrane Insert-based Infection System to Study the Effects of Secreted Bacterial Toxins on Mammalian Host Cells09:25

Implementation of a Permeable Membrane Insert-based Infection System to Study the Effects of Secreted Bacterial Toxins on Mammalian Host Cells

Published on: August 19, 2016

Purification of Human S100A12 and Its Ion-induced Oligomers for Immune Cell Stimulation12:55

Purification of Human S100A12 and Its Ion-induced Oligomers for Immune Cell Stimulation

Published on: September 29, 2019

Related Concept Videos

Antimicrobial Proteins01:23

Antimicrobial Proteins

Antimicrobial proteins are important components of the immune system. They aid the body in combating pathogens by either killing them directly or hindering their replication processes. Four main types of antimicrobial substances are interferons, the complement system, iron-binding proteins, and antimicrobial proteins.
Interferons
Interferons (IFNs) are proteins produced by lymphocytes, macrophages, and fibroblasts infected with viruses. While IFNs cannot prevent viruses from entering and...
Hypersensitivity Reactions: Cytolytic Reactions01:01

Hypersensitivity Reactions: Cytolytic Reactions

Type II hypersensitivity involves IgG and IgM antibodies targeting cell surface antigens, leading to cell destruction. This can occur through complement activation, antibody-dependent cell-mediated cytotoxicity (ADCC), or acting as opsonins for phagocytosis. When excessive, these reactions cause significant tissue damage.Drug-induced hemolytic anemia is a common example, where drugs like penicillin or cephalosporins bind to red blood cells, forming drug-protein complexes. These complexes...
Bacterial Toxins01:12

Bacterial Toxins

Bacterial toxins are sophisticated virulence factors that enable pathogenic bacteria to interact with, invade, and damage host tissues. These toxins fall broadly into two types: protein exotoxins, which are secreted into the environment and target specific host receptors, and lipopolysaccharide endotoxins, which are structural components of the bacterial outer membrane released primarily during bacterial lysis or membrane shedding. Exotoxins generally act more selectively, binding to cell...
Determinants of Bacterial Pathogenicity and Virulence01:20

Determinants of Bacterial Pathogenicity and Virulence

Pathogenic bacteria employ a variety of strategies to establish infections, including the secretion of extracellular enzymes that act as potent virulence factors. These enzymes facilitate bacterial colonization of host tissues and help evade immune surveillance. By targeting structural components of host tissues and interfering with immune mechanisms, these enzymes play a pivotal role in disease progression.Extracellular Enzymes Facilitating Tissue Invasion: Several bacterial pathogens secrete...
Diphtheria01:28

Diphtheria

Diphtheria is an acute, toxin-mediated infectious disease that primarily affects the upper respiratory tract. It is caused by Corynebacterium diphtheriae, a Gram-positive, pleomorphic rod that lacks spore-forming capability and exhibits a characteristic club-shaped morphology under microscopic examination. While C. diphtheriae can asymptomatically colonize mucosal surfaces, clinical disease manifests only when the bacterial strain is lysogenized by a specific β-corynephage. This phage...
Inhibitors of Bacterial Protein Synthesis01:25

Inhibitors of Bacterial Protein Synthesis

Aminoglycosides constitute a highly potent class of bactericidal antibiotics that exert their antimicrobial effects by targeting the bacterial ribosome, specifically disrupting protein synthesis. These polycationic molecules consist of amino-modified sugars linked via glycosidic bonds to an aminocyclitol core such as 2-deoxystreptamine or streptamine. Their strong positive charges facilitate tight binding to the negatively charged phosphate backbone of ribosomal RNA (rRNA), primarily at the 16S...