Related Experiment Video

Updated: Sep 9, 2026

Evaluation of Host-Pathogen Responses and Vaccine Efficacy in Mice
08:52

Evaluation of Host-Pathogen Responses and Vaccine Efficacy in Mice

Published on: February 22, 2019

Virulence factors determine attachment and ingestion of nonopsonized and opsonized Bordetella pertussis by human

W L Hazenbos1, B M van den Berg, J W van't Wout

  • 1Department of Infectious Diseases, University Hospital, Leiden, The Netherlands.

Infection and Immunity
|November 1, 1994
PubMed

Insights

Virulence factors on Bordetella pertussis mediate bacterial attachment to human monocytes. However, these factors also inhibit the engulfment (phagocytosis) of B. pertussis by monocytes, especially when opsonized.

Area of Science:

  • Immunology
  • Microbiology
  • Cell Biology

Background:

  • Bordetella pertussis, the causative agent of whooping cough, interacts with human immune cells.
  • Understanding these interactions is crucial for developing effective vaccines and treatments.
  • The roles of bacterial virulence factors and host opsonization in these interactions are not fully elucidated.

Purpose of the Study:

  • To investigate the role of Bordetella pertussis virulence factors in monocyte attachment and ingestion.
  • To determine the effect of opsonization on the interaction between B. pertussis and human monocytes.
  • To differentiate between bacterial attachment and phagocytosis by monocytes.

Main Methods:

  • Utilized virulent and avirulent Bordetella pertussis strains, including mutants deficient in specific virulence factors (filamentous hemagglutinin, fimbriae, pertactin).
  • Assessed bacterial attachment to human monocytes in the absence of opsonins.
  • Quantified bacterial ingestion (phagocytosis) by monocytes with and without serum opsonization.

Main Results:

  • Non-opsonized virulent B. pertussis attached to monocytes, mediated by filamentous hemagglutinin, fimbriae, and pertactin.
  • Non-opsonized avirulent B. pertussis showed no significant attachment to monocytes.
  • Opsonization enhanced the ingestion of both virulent and avirulent B. pertussis by monocytes, but virulence factors were found to inhibit this opsonin-mediated process.

Conclusions:

  • Fimbriae and pertactin are key virulence factors for the adherence of non-opsonized virulent B. pertussis to monocytes.
  • Filamentous hemagglutinin also plays a significant role in bacterial adherence.
  • B. pertussis virulence factors actively inhibit opsonin-mediated phagocytosis by monocytes, suggesting a mechanism to evade immune clearance.

More Related Videos

Opsono-Adherence Assay to Evaluate Functional Antibodies in Vaccine Development Against Bacillus anthracis and Other Encapsulated Pathogens13:47

Opsono-Adherence Assay to Evaluate Functional Antibodies in Vaccine Development Against Bacillus anthracis and Other Encapsulated Pathogens

Published on: May 19, 2020

Automated, High-Throughput Detection of Bacterial Adherence to Host Cells07:21

Automated, High-Throughput Detection of Bacterial Adherence to Host Cells

Published on: September 17, 2021

Related Concept Videos

Receptor-mediated Endocytosis01:48

Receptor-mediated Endocytosis

Receptor-mediated endocytosis is a process through which bulk amounts of specific molecules can be imported into a cell after binding to cell surface receptors. The molecules bound to these receptors are taken into the cell through inward folding of the cell surface membrane, which is eventually pinched off into a vesicle within the cell. Structural proteins, such as clathrin, coat the budding vesicle and give it its round form.Clathrin-Mediated Endocytosis of LDLOne well-characterized example...
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...
Defense Against Bacterial Pathogens01:31

Defense Against Bacterial Pathogens

The human immune system is a complex network of cells, tissues, and organs that work together to defend the body against bacterial infections. It consists of various immune cells, each playing a specific role in the defense mechanism.
Phagocytes
Phagocytes are the frontline soldiers of the immune system. They include neutrophils and macrophages. Neutrophils are the most abundant type of white blood cell and are quickly mobilized to the site of infection. Macrophages are larger cells that patrol...
Colonisation of Pathogens01:25

Colonisation of Pathogens

Pathogen colonization of host tissues is a critical step in the development of infectious diseases. Various pathogenic microorganisms, including bacteria, fungi, viruses, and protozoa, have evolved complex strategies to attach to, invade, and persist within host environments. These mechanisms enable pathogens to establish infections, evade immune responses, and resist antimicrobial treatments.Attachment to Host CellsIn bacteria, colonization typically begins with adherence to host epithelial...
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...
Regulation of Bacterial Virulence01:28

Regulation of Bacterial Virulence

Pathogenic bacteria employ a range of regulatory mechanisms to modulate the expression of virulence genes in response to environmental and host-derived signals. These mechanisms ensure that virulence factors are expressed only under favorable conditions, thereby optimizing infection and survival strategies.Mechanisms of Virulence RegulationKey regulatory strategies include:Two-Component Systems: These consist of a membrane-bound sensor kinase and a cytoplasmic response regulator. Environmental...