Related Experiment Video

Updated: Sep 21, 2025

Analyzing Platelet Subpopulations by Multi-color Flow Cytometry
08:04

Analyzing Platelet Subpopulations by Multi-color Flow Cytometry

Published on: June 10, 2025

432

Group B Streptococcal Hemolytic Pigment Impairs Platelet Function in a Two-Step Process

Kristin Jahn1, Patience Shumba1, Phoenicia Quach2

  • 1Center for Functional Genomics of Microbes, Department of Molecular Genetics and Infection Biology, Interfaculty Institute for Genetics and Functional Genomics, University of Greifswald, 17489 Greifswald, Germany.

Cells
|May 28, 2022
PubMed

Insights

Group B streptococci pigment activates and then kills human platelets, a key factor in severe infections. This finding reveals a novel mechanism for platelet destruction during GBS disease.

Area of Science:

  • Microbiology and Immunology
  • Hematology

Background:

  • Group B streptococci (GBS) are increasingly implicated in invasive infections beyond maternal-fetal contexts, including sepsis and toxic shock syndrome.
  • These severe GBS infections are frequently associated with coagulation disorders and low platelet counts (thrombocytopenia).
  • GBS produce a pigment toxin with hemolytic, cytolytic, and coagulatory properties.

Purpose of the Study:

  • To investigate the direct impact of the GBS pigment toxin on human platelets.
  • To elucidate the mechanism by which GBS pigment affects platelet function and viability.

Main Methods:

  • Exposure of human platelets to GBS expressing the pigment toxin.
  • Assessment of platelet activation markers and cell death following GBS pigment interaction.

Main Results:

  • Infection with pigmented GBS initially triggered activation of human platelets.
  • Prolonged exposure led to necrotic cell death in the affected platelets.
  • The GBS pigment toxin was identified as the causative agent for platelet demise.

Conclusions:

  • The GBS pigment toxin plays a critical role in the pathogenesis of GBS-associated coagulopathies.
  • GBS pigment directly induces platelet activation followed by necrotic cell death, contributing to thrombocytopenia.
  • This study demonstrates that GBS pigment is a potent platelet-killing factor.

Keywords:
Streptococcus agalactiaegroup B streptococcuspigmentplatelets

More Related Videos

Procoagulant Platelet Characterization by Measuring Phosphatidylserine Exposure and Microvesicle Release from Human Purified Platelets05:49

Procoagulant Platelet Characterization by Measuring Phosphatidylserine Exposure and Microvesicle Release from Human Purified Platelets

Published on: November 29, 2024

733
Microfluidics in Assessing Platelet Function06:47

Microfluidics in Assessing Platelet Function

Published on: November 8, 2024

1.1K

Related Concept Videos

Formation of the Platelet Plug01:22

Formation of the Platelet Plug

The platelet phase, the second stage of hemostasis, commences around 15-20 seconds after an injury. It follows and overlaps with the vascular phase, during which blood vessels constrict to minimize blood loss.
As the injured blood vessel contracts, endothelial cells undergo contraction, revealing collagen fibers in the basement membrane and underlying connective tissue. Furthermore, the plasma membrane of endothelial cells becomes adhesive, preparing the site for platelet adhesion. Platelets...
7.2K
Structure and Function of Platelets01:18

Structure and Function of Platelets

The cell fragments known as platelets are disc-shaped, with an average diameter of about 3 μm and a thickness of roughly 1 μm. They play a crucial role in the body's vascular clotting system, which also involves plasma proteins, blood cells, and blood vessel tissues.
Platelets are continually replenished, circulating in the bloodstream for 9-12 days before being removed by phagocytes, primarily in the spleen. A microliter of circulating blood contains between 150,000 and 450,000...
1.6K
Introduction to Hemostasis01:05

Introduction to Hemostasis

Hemostasis is a complex physiological process that prevents excessive bleeding when a blood vessel is injured. It's crucial for maintaining the integrity of the circulatory system, as it ensures that our blood remains fluid while still within the vascular network and yet clots to prevent blood loss upon vessel injury.
The three phases of hemostasis involve many clotting factors present in plasma and several substances released by platelets and injured tissue cells. It is a fast, localized,...
9.0K
Extrinsic and Intrinsic Pathways of Hemostasis01:20

Extrinsic and Intrinsic Pathways of Hemostasis

Blood clotting or coagulation involves extrinsic and intrinsic pathways, which ultimately merge into the common pathway, forming a fibrin clot.
The Extrinsic Pathway
The extrinsic pathway of coagulation is typically initiated by tissue damage that exposes blood to tissue factor (TF), a protein released by the damaged tissue cells outside the blood vessels—this interaction with TF triggers biochemical reactions involving specific clotting factors. The key player here is Factor VII, which...
9.3K
Disorders of Hemostasis01:24

Disorders of Hemostasis

Hemostasis, the process that stops bleeding after a blood vessel injury, is crucial for maintaining the integrity of the circulatory system. However, disorders of hemostasis can disrupt this delicate balance, leading to either excessive clotting or bleeding. These disorders can be broadly classified into thromboembolic disorders and bleeding disorders.
Thromboembolic Disorders
Two factors primarily cause thromboembolic conditions.
1.2K
Coagulation01:09

Coagulation

The coagulation phase is a critical part of the body's process to prevent blood loss following injury to blood vessels. It involves chemical reactions that form a clot to seal the injured area. The clotting process begins shortly after injury, within 15-20 seconds for severe damage and 1-2 minutes for minor injuries.
During the coagulation phase, clotting factors, or procoagulants, play a vital role in initiating and progressing the coagulation cascade. This cascade is a series of reactions...
7.5K