Related Experiment Video
Updated: Apr 19, 2026

09:01
An In vitro Model to Study Immune Responses of Human Peripheral Blood Mononuclear Cells to Human Respiratory Syncytial Virus Infection
Published on: December 10, 2013
8.5K
TLR4 genotype and environmental LPS mediate RSV bronchiolitis through Th2 polarization
The Journal of Clinical Investigation
|January 3, 2015
Summary
Respiratory Syncytial Virus (RSV) disease severity in infants is influenced by Toll-like receptor 4 (TLR4) genotype and lipopolysaccharide (LPS) exposure. A high IL-4/IFN-γ ratio indicates severe RSV infection and Th2 polarization.
Area of Science:
- Immunology
- Virology
- Genetics
Background:
- Respiratory Syncytial Virus (RSV) causes bronchiolitis in 30%-70% of infected infants, with 2% requiring hospitalization.
- Disease severity varies among infants, with proposed factors including virus titers, inflammation, and T-helper 2 (Th2) bias.
- The role of Toll-like receptor 4 (TLR4) in RSV pathogenesis is debated, despite its association with disease phenotypes.
Purpose of the Study:
- To investigate the interaction between TLR4 and environmental factors in RSV disease.
- To identify immune mediators associated with severe RSV illness.
- To define the genetic and environmental determinants of RSV disease severity.
Main Methods:
- Analysis of two independent infant populations with RSV bronchiolitis.
- Evaluation of TLR4 genotype and environmental lipopolysaccharide (LPS) exposure.
- Assessment of immune mediators, including GATA3/T-bet and IL-4/IFN-γ ratios in respiratory secretions.
- Confirmation using murine models of RSV infection.
Main Results:
- RSV infection severity is determined by individual TLR4 genotype and environmental LPS exposure.
- Infants with severe RSV disease exhibited a high GATA3/T-bet ratio, correlating with a high IL-4/IFN-γ ratio in respiratory secretions.
- A high IL-4/IFN-γ ratio signifies Th2 polarization, associated with severe RSV illness.
- Murine models confirmed the influence of LPS exposure, Tlr4 genotype, and Th2 polarization on disease phenotypes.
Conclusions:
- Environmental and genetic factors significantly influence RSV pathogenesis.
- A high IL-4/IFN-γ ratio is a key indicator of severe RSV disease.
- TLR4 genotype and LPS exposure are critical determinants of RSV disease severity.
- Immune mediators like IL-4 and IFN-γ present potential therapeutic targets for RSV intervention.
More Related Videos
Related Concept Videos
Asthma I: Introduction
3
Asthma is a chronic inflammatory disorder of the airways characterized by variable airflow obstruction and heightened bronchial responsiveness to a wide range of triggers. The underlying inflammation leads to airway swelling, mucus hypersecretion, and smooth muscle constriction, all of which narrow the airway lumen and impede airflow. Clinically, asthma presents with recurrent episodes of wheezing, shortness of breath, chest tightness, and coughing, symptoms that typically vary in intensity and...
3
Microbiota of the Respiratory Tract
47
The human respiratory tract, comprising the upper and lower segments, serves as a critical interface with the external environment. The upper respiratory tract (URT)—including the nostrils, sinuses, pharynx, and oropharynx—is heavily colonized by microbes, while the lower respiratory tract (LRT), composed of the larynx, trachea, bronchi, and lungs, was long thought to be sterile. However, recent molecular studies have revealed that the lungs are not devoid of microbes but act more...
47
Chronic Obstructive Pulmonary Disease III: Chronic Bronchitis Features
2
Chronic bronchitis is a key phenotype of chronic obstructive pulmonary disease (COPD), characterized by airway-centered inflammation and mucus overproduction. It develops from long-term exposure to harmful particles or gases, most commonly cigarette smoke, which triggers a persistent inflammatory response.Cellular and Structural ChangesInflammation initially affects the large bronchi and later the smaller airways, with infiltration by immune cells, including neutrophils, macrophages, and...
2
T Cell Types and Functions
3.5K
When T cells with CD4 markers are activated, they give rise to two types of effector cells: helper T cells and regulatory T cells. Meanwhile, T cells with CD8 markers differentiate into effector cytotoxic T cells. The differentiation of CD4 T cells into helper T cell subsets, such as Th1, Th2, and Th17 cells, is dependent on the antigen type, antigen-presenting cell, and regulatory cytokines.
Th1 cells stimulate dendritic cells to express necessary co-stimulatory molecules on their surfaces for...
Th1 cells stimulate dendritic cells to express necessary co-stimulatory molecules on their surfaces for...
3.5K
Formation of Lipopolysaccharides
1.1K
Lipopolysaccharides (LPS) are crucial components of the outer membrane of Gram-negative bacteria, serving both structural and functional roles. It contributes to membrane stability and protects bacteria from host immune responses. LPS is composed of three major regions—lipid A, a core oligosaccharide, and an O antigen. The biosynthesis and assembly of LPS involve a highly coordinated set of enzymatic reactions and transport mechanisms. Additionally, LPS is recognized as an endotoxin,...
1.1K
Asthma-II: Pathophysiology and Classification
5.0K
Asthma is a prevalent chronic respiratory condition marked by inflammation and hyperresponsiveness of the airways. Its pathophysiology involves complex interactions among inflammatory pathways, immune responses, and neural mechanisms.
Additionally, environmental and genetic factors play crucial roles in determining an individual's susceptibility to asthma and the severity of their condition.
Critical processes in asthma pathophysiology include:
Additionally, environmental and genetic factors play crucial roles in determining an individual's susceptibility to asthma and the severity of their condition.
Critical processes in asthma pathophysiology include:
5.0K

