Related Experiment Video

Updated: Jul 26, 2026

Experimental Human Pneumococcal Carriage
07:47

Experimental Human Pneumococcal Carriage

Published on: February 15, 2013

Identification of hBD-3 in respiratory tract and serum: the increase in pneumonia

H Ishimoto1, H Mukae, Y Date

  • 1Second Dept of Internal Medicine, Nagasaki University School of Medicine, Japan.

The European Respiratory Journal
|February 3, 2006
PubMed

Insights

Human beta-defensin-3 (hBD-3) peptide, an antimicrobial molecule, is present in the human respiratory system and exhibits potent antimicrobial activity. Its presence in lung tissue and elevated serum levels during pneumonia suggest a role in respiratory infections.

Area of Science:

  • Immunology
  • Microbiology
  • Pulmonology

Background:

  • Human beta-defensin-3 (hBD-3) is an antimicrobial peptide found in human skin.
  • hBD-3 mRNA is detected in airways, suggesting a potential role in respiratory antimicrobial defenses.
  • The presence of hBD-3 peptide in the respiratory system remained unconfirmed.

Purpose of the Study:

  • To confirm the presence and localization of hBD-3 peptide in the human respiratory system.
  • To assess the antimicrobial activity of hBD-3 peptide.
  • To measure serum concentrations of hBD-3 in patients with bacterial pneumonia.

Main Methods:

  • Radial diffusion assay and colony count assay for antimicrobial activity.
  • Reverse-phase HPLC coupled with RIA for peptide detection in lung and serum.
  • Immunohistochemistry for hBD-3 localization.
  • RIA for serum hBD-3 concentration measurement.

Main Results:

  • Synthesized hBD-3 peptide demonstrated strong antimicrobial activity, unaffected by salt concentrations.
  • hBD-3 peptide was confirmed in human lung homogenates and serum.
  • Immunohistochemistry revealed hBD-3 expression in bronchial and bronchiolar epithelial cells.
  • Mean serum hBD-3 levels were higher in acute bacterial pneumonia (239.4 pg/mL) compared to post-therapy (159.3 pg/mL).

Conclusions:

  • hBD-3 peptide is present in the human respiratory tract and exhibits significant antimicrobial properties.
  • Findings elucidate hBD-3's role in host immune responses within the respiratory system.
  • hBD-3 may have pathophysiological significance in respiratory infections, particularly bacterial pneumonia.

More Related Videos

An In vitro Model to Study Immune Responses of Human Peripheral Blood Mononuclear Cells to Human Respiratory Syncytial Virus Infection09:01

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

Experimental Model to Evaluate Resolution of Pneumonia09:49

Experimental Model to Evaluate Resolution of Pneumonia

Published on: February 17, 2023

Related Concept Videos

Pneumonia I: Introduction01:30

Pneumonia I: Introduction

Pneumonia is an acute respiratory infection that targets the lungs, specifically the alveoli. These tiny air sacs, essential for oxygen exchange, become engorged with pus and fluid, severely hindering breathing, decreasing oxygen absorption, and causing significant pain and discomfort during respiration.
Risk Factors
Various factors influence the likelihood of developing pneumonia. Age plays a crucial role, with infants, children under two, and individuals over 65 at increased risk due to their...
Pneumonia II: Pathophysiology01:29

Pneumonia II: Pathophysiology

The pathophysiology of pneumonia involves the following steps:
Pneumonia III: Complications and Assessment01:30

Pneumonia III: Complications and Assessment

Pneumonia poses the potential for numerous complications that warrant consideration. These complications include the following:
Pneumonia IV: Management01:28

Pneumonia IV: Management

The treatment of pneumonia varies based on its severity and the causative pathogen. Here is a structured approach to managing pneumonia, integrating pharmaceutical and supportive care strategies.
Bacterial Pneumonia Treatment
For bacterial pneumonia, antibiotics serve as the cornerstone of therapy. Initial treatment often begins with empirical antibiotics, tailored to the anticipated causative organism and adjusted based on culture results. Key antibiotic choices include:
Atypical Pneumonia01:14

Atypical Pneumonia

Atypical pneumonia, often caused by Mycoplasma pneumoniae, is a form of pulmonary infection that differs from the classical presentation of bacterial pneumonia in both its cause and clinical symptoms. Mycoplasma pneumoniae is a pleomorphic bacterium notable for its lack of a rigid cell wall. This structural characteristic imparts resistance to beta-lactam antibiotics and significantly influences the bacterium’s behavior within the human host.Other pathogens responsible for the disease include...
Pneumonia I: Introduction01:29

Pneumonia I: Introduction

Pneumonia is an infection of the lower respiratory tract that leads to inflammation of the lung parenchyma, often resulting in the accumulation of inflammatory exudate in the alveoli and airways. Unlike the watery, low-protein fluid exudate in pulmonary edema, the exudate in this case is a thick fluid rich in immune cells, proteins, and debris produced during infection and inflammation.This impairs gas exchange and can lead to consolidation of lung tissue. The infection may be caused by a...