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Microscopy-based Assays for High-throughput Screening of Host Factors Involved in Brucella Infection of Hela Cells
Published on: August 5, 2016
Brucella melitensis invades murine erythrocytes during infection
Marie-Alice Vitry1, Delphine Hanot Mambres1, Michaël Deghelt1
1Unité de Recherche en Biologie des Microorganismes, Laboratoire d'Immunologie et de Microbiologie, NARILIS, University of Namur (UNamur), Namur, Belgium.
Abstract:
Brucella spp. are facultative intracellular Gram-negative coccobacilli responsible for brucellosis, a worldwide zoonosis. We observed that Brucella melitensis is able to persist for several weeks in the blood of intraperitoneally infected mice and that transferred blood at any time point tested is able to induce infection in naive recipient mice. Bacterial persistence in the blood is dramatically impaired by specific antibodies induced following Brucella vaccination. In contrast to Bartonella, the type IV secretion system and flagellar expression are not critically required for the persistence of Brucella in blood. ImageStream analysis of blood cells showed that following a brief extracellular phase, Brucella is associated mainly with the erythrocytes. Examination by confocal microscopy and transmission electron microscopy formally demonstrated that B. melitensis is able to invade erythrocytes in vivo. The bacteria do not seem to multiply in erythrocytes and are found free in the cytoplasm. Our results open up new areas for investigation and should serve in the development of novel strategies for the treatment or prophylaxis of brucellosis. Invasion of erythrocytes could potentially protect the bacterial cells from the host's immune response and hamper antibiotic treatment and suggests possible Brucella transmission by bloodsucking insects in nature.
Insights
Brucella melitensis persists in mouse blood, infecting recipients via blood transfusion. Erythrocyte invasion by Brucella may evade immune responses and hinder treatment, suggesting new therapeutic targets.
Area of Science:
- Microbiology
- Immunology
- Infectious Diseases
Background:
- Brucella spp. cause brucellosis, a global zoonotic disease.
- Brucella are Gram-negative coccobacilli that survive intracellularly.
- Understanding Brucella's persistence mechanisms is crucial for disease control.
Purpose of the Study:
- To investigate the persistence of Brucella melitensis in mouse blood.
- To determine the role of erythrocytes in Brucella blood persistence.
- To explore potential implications for brucellosis treatment and transmission.
Main Methods:
- Intraperitoneal infection of mice with Brucella melitensis.
- Blood transfusion experiments to assess infectivity.
- ImageStream, confocal, and transmission electron microscopy to examine bacterial-host cell interactions.
- Evaluation of antibody effects on bacterial persistence.
Main Results:
- Brucella melitensis persisted in mouse blood for weeks, capable of infecting naive recipients.
- Bacterial persistence was significantly reduced by vaccination-induced antibodies.
- Brucella invaded erythrocytes in vivo, residing within the cytoplasm without apparent multiplication.
- Type IV secretion system and flagellar expression were not critical for blood persistence.
Conclusions:
- Brucella melitensis invades erythrocytes, potentially offering protection from immune responses and antibiotics.
- Erythrocyte invasion by Brucella may influence treatment strategies and disease transmission routes.
- Further research into erythrocyte invasion is warranted for developing novel brucellosis interventions.
