Related Experiment Video

Updated: Sep 13, 2026

Invasion of Human Cells by a Bacterial Pathogen
07:15

Invasion of Human Cells by a Bacterial Pathogen

Published on: March 21, 2011

M protein mediates streptococcal adhesion to HEp-2 cells

J R Wang1, M W Stinson

  • 1Department of Microbiology, School of Medicine and Biomedical Sciences, State University of New York at Buffalo 14214-3005.

Infection and Immunity
|February 1, 1994
PubMed

Insights

Streptococcus pyogenes adhesion to human cells is mediated by M protein. This bacterial adhesin directly binds to specific human epithelial cell membrane components, facilitating infection.

Area of Science:

  • Microbiology
  • Cell Biology
  • Immunology

Background:

  • Streptococcus pyogenes is a pathogen that adheres to human epithelial cells.
  • Identifying bacterial adhesins is crucial for understanding infection mechanisms.

Purpose of the Study:

  • To identify the specific Streptococcus pyogenes adhesins responsible for binding to human epithelial cells.
  • To elucidate the interaction between bacterial components and host cell surface receptors.

Main Methods:

  • Extraction of S. pyogenes M6 cell wall components.
  • Incubation of HEp-2 cells with bacterial extracts and analysis via Western blot.
  • Use of pepsin-cleaved M protein fragments and labeled lipoteichoic acid.
  • Comparison of adhesion between M+ and M- S. pyogenes strains.

Main Results:

  • M protein (62 kDa) was identified as the sole S. pyogenes component binding to HEp-2 cells.
  • M protein binds to trypsin-sensitive HEp-2 cell components (97 and 205 kDa).
  • Lipoteichoic acid did not mediate M protein binding; M-deficient strains showed significantly reduced adhesion.

Conclusions:

  • M protein directly binds to specific human epithelial cell membrane components.
  • M protein is a key mediator of Streptococcus pyogenes adhesion to host cells.

More Related Videos

In Vitro Assay of Bacterial Adhesion onto Mammalian Epithelial Cells05:57

In Vitro Assay of Bacterial Adhesion onto Mammalian Epithelial Cells

Published on: May 16, 2011

Biomimetic Materials to Characterize Bacteria-host Interactions12:22

Biomimetic Materials to Characterize Bacteria-host Interactions

Published on: November 16, 2015

Related Concept Videos

Intracellular Signaling Affects Focal Adhesions01:17

Intracellular Signaling Affects Focal Adhesions

Integrins act both as extracellular input receivers and as intracellular processing activators. As their name suggests, integrins are entirely integrated into the membrane structure. Their hydrophobic membrane-spanning regions interact with the phospholipid bilayer's hydrophobic region. These membrane receptors provide extracellular attachment sites for effectors like hormones and growth factors. They activate intracellular response cascades when their effectors are bound and active.
Some...
Adherens Junctions01:24

Adherens 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...
Cell Adhesion Molecules - Types and Functions01:20

Cell Adhesion Molecules - Types and Functions

Cell adhesion molecules (CAMs) are pivotal to multicellularity and the coordinated functioning of tissues and organ systems. They enable physical interactions between cells and provide mechanical strength to tissues. They also function as receptors for signal transmission across the plasma membrane. The CAMs are broadly classified into four families - integrins, cadherins, selectins, and immunoglobulin-like CAMs (IgCAMs).
CAM Families
The Integrin family of proteins is primarily  involved in a...
Selectins01:25

Selectins

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...
Immunoglobulin-like Cell Adhesion Molecules01:31

Immunoglobulin-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...
Streptococcal Pharyngitis01:27

Streptococcal Pharyngitis

Streptococcal pharyngitis, commonly known as “strep throat,” is an acute infection of the oropharyngeal tissues caused by the Gram‑positive Group A Streptococcus (Streptococcus pyogenes). Transmission occurs primarily through respiratory droplets expelled during coughing, sneezing, or talking.Mechanisms of Host Entry and Immune EvasionUpon entering the host, S. pyogenes adheres to the mucosal epithelial cells of the pharynx via surface proteins, notably lipoteichoic acid and the antiphagocytic...