scholarly journals Use of Flow Cytometry to Evaluate Phagocytosis of Staphylococcus aureus by Human Neutrophils

2021 ◽  
Vol 12 ◽  
Author(s):  
Elena Boero ◽  
Iris Brinkman ◽  
Thessely Juliet ◽  
Eline van Yperen ◽  
Jos A. G. van Strijp ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Flow Cytometry ◽  
Immune Responses ◽  
Human Neutrophils ◽  
Host Proteins ◽  
Flow Cytometry Assay ◽  
Immune Therapies ◽  
Human Immune Response ◽  
Human Immune ◽  
Phagocytic Uptake

Neutrophils play a key role in the human immune response to Staphylococcus aureus infections. These professional phagocytes rapidly migrate to the site of infection to engulf bacteria and destroy them via specialized intracellular killing mechanisms. Here we describe a robust and relatively high-throughput flow cytometry assay to quantify phagocytosis of S. aureus by human neutrophils. We show that effective phagocytic uptake of S. aureus is greatly enhanced by opsonization, i.e. the tagging of microbial surfaces with plasma-derived host proteins like antibodies and complement. Our rapid assay to monitor phagocytosis can be used to study neutrophil deficiencies and bacterial evasion, but also provides a powerful tool to assess the opsonic capacity of antibodies, either in the context of natural immune responses or immune therapies.

scholarly journals Immune Response toward Mycobacterium Tuberculosis Infection

2020 ◽  
Vol 2 (2) ◽  
pp. 77-87
Author(s):  
Abdi Dzul Ikram Hasanuddin ◽  
Nanang Roswita ◽  
Ivan Virnanda Amu
Keyword(s):  
Immune Response ◽  
Mycobacterium Tuberculosis ◽  
Immune Responses ◽  
Tuberculosis Infection ◽  
Mycobacterium Tuberculosis Infection ◽  
Adaptive Immune ◽  
Human Immune Response ◽  
Exogenous Factors ◽  
Human Immune ◽  
Microfold Cells

Understanding the human immune response toward Mycobacterium tuberculosis infection is important for controlling its infection. Its transmission through the air consists of "droplets nuclei" containing TB bacilli. After initial infection, the human body will provide diverse immune responses and will determine different clinico-histopathologic finding. This response starts from innate immunity that consists of phagocytosis by distal alveolar macrophages or nasal microfold cells, then will be continued by dendritic cells to be transferred to mediastinal lymph nodes to induced adaptive immune responses. This response is mediated by cells through IFN- γ signaling which will enhance phagocytosis. If this response is effective, there will be a latent infection with an initial histopathological finding of caseosa granulomas and predominantly followed by chronic granulomas. In a few cases, it can be reactivated via the IL-10 activation pathway and exogenous factors, it will induce a great adaptive immune reaction and provide more severe clinico-histopathological manifestation. The existence of the human body's immune response to Mycobacterium tuberculosis, etiher innate or adaptive immunity will determine the clinical course and pathology that will occur.

scholarly journals Variation in Gamma Interferon Responses to Different Infecting Strains of Mycobacterium tuberculosis in Acid-Fast Bacillus Smear-Positive Patients and Household Contacts in Antananarivo, Madagascar

2010 ◽  
Vol 17 (7) ◽  
pp. 1094-1103 ◽  
Author(s):  
Niaina Rakotosamimanana ◽  
Vaomalala Raharimanga ◽  
Soa Fy Andriamandimby ◽  
Jean-Louis Soares ◽  
T. Mark Doherty ◽  
...  
Keyword(s):  
Immune Response ◽  
Mycobacterium Tuberculosis ◽  
Immune Responses ◽  
Gamma Interferon ◽  
Clinical Strains ◽  
Household Contacts ◽  
Human Immune Response ◽  
Ifn Γ ◽  
Human Immune ◽  
Index Cases

ABSTRACT The majority of healthy individuals exposed to Mycobacterium tuberculosis will not develop tuberculosis (TB), though many may become latently infected. More precise measurement of the human immune response to M. tuberculosis infection may help us understand this difference and potentially identify those subjects most at risk of developing active disease. Gamma interferon (IFN-γ) production has been widely used as a proxy marker to study infection and to examine the human immune response to specific M. tuberculosis antigens. It has been suggested that genetically distinct M. tuberculosis strains may invoke different immune responses, although how these differences influence the immune responses and clinical outcome in human tuberculosis is still poorly understood. We therefore evaluated the antigen-specific IFN-γ production responses in peripheral blood mononuclear cells from two cohorts of subjects recruited in Antananarivo, Madagascar, from 2004 to 2006 and examined the influence of the infecting M. tuberculosis strains on this response. The cohorts were sputum-positive index cases and their household contacts. Clinical strains isolated from the TB patients were typed by spoligotyping. Comparison of the IFN-γ responses with the spoligotype of the infecting clinical strains showed that “modern” M. tuberculosis strains, like Beijing and Central Asian (CAS) strains, tended to induce lower IFN-γ responses than “ancient” strains, like East African-Indian (EAI) strains, in index cases and their household contacts. These results suggest that new strains may have evolved to induce a host response different from that of ancient strains. These findings could have important implications in the development of therapeutic and diagnostic strategies.

Immune responses during cutaneous and visceral leishmaniasis

Parasitology ◽  
2014 ◽  
Vol 141 (12) ◽  
pp. 1544-1562 ◽  
Author(s):  
LUKASZ KEDZIERSKI ◽  
KRYSTAL J. EVANS
Keyword(s):  
Immune Response ◽  
Immune Responses ◽  
Vaccine Development ◽  
Current Treatment ◽  
Acquired Immunity ◽  
Insect Vector ◽  
Protozoan Parasites ◽  
Human Immune Response ◽  
Human Immune ◽  
Significant Health

SUMMARYLeishmaniaare protozoan parasites spread by a sandfly insect vector and causing a spectrum of diseases collectively known as leishmaniasis. The disease is a significant health problem in many parts of the world, resulting in an estimated 1·3 million new cases and 30 000 deaths annually. Current treatment is based on chemotherapy, which is difficult to administer, expensive and becoming ineffective in several endemic regions. To date there is no vaccine against leishmaniasis, although extensive evidence from studies in animal models indicates that solid protection can be achieved upon immunization. This review focuses on immune responses toLeishmaniain both cutaneous and visceral forms of the disease, pointing to the complexity of the immune response and to a range of evasive mechanisms utilized by the parasite to bypass those responses. The amalgam of innate and acquired immunity combined with the paucity of data on the human immune response is one of the major problems currently hampering vaccine development and implementation.

scholarly journals Assessment of the oxidative metabolism of calves’ bronchoalveolar cells: comparison between NBT and fluorimetric techniques

2018 ◽  
Vol 85 (0) ◽  
Author(s):  
Bruna Artner ◽  
Angela Reck ◽  
Alessandra Mayer Coelho ◽  
Julio José Prediger ◽  
Desiree Vera Pontarolo ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Flow Cytometry ◽  
Alveolar Macrophages ◽  
Oxidative Metabolism ◽  
Therapeutic Dose ◽  
Flow Cytometry Assay ◽  
Colorimetric Test ◽  
Healthy Cattle ◽  
The Difference ◽  
Cattle Husbandry

ABSTRACT: Evaluation of alveolar macrophage functions of cattle is an important tool in order to assess whether measures taken during the cattle husbandry can decrease the respiratory tract defense. The aim of this study was to determine whether dexamethasone used at therapeutic dose can affect the oxidative metabolism of alveolar macrophages of cattle. This was evaluated by two tests, the fluorometric and colorimetric. The similarity of the results was studied, using alveolar macrophages of six healthy cattle, obtained from bronchoalveolar lavage on a basal and an immunosuppressant moment after the application of dexamethasone. For the fluorometric test, alveolar macrophages were incubated with Staphylococcus aureus and 2’-7’dichlorohidroflurescein, and analyzed by flow cytometer. For the colorimetric test, alveolar macrophages were incubated with Phorbol 12- miristate-13 acetate and nitroblue tetrazolium, dissolved and analyzed in a spectrophotometer. It was noted that dexamethasone therapeutic dose (0.05 mg/kg) reduced the functions of alveolar macrophages from healthy bovine. This result was observed by both tests with the difference that the flow cytometry assay was more informative for identifying which specific cellular function has been compromised.

scholarly journals Temperate Bacteriophages—The Powerful Indirect Modulators of Eukaryotic Cells and Immune Functions

Viruses ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1013
Author(s):  
Martyna Cieślik ◽  
Natalia Bagińska ◽  
Ewa Jończyk-Matysiak ◽  
Alicja Węgrzyn ◽  
Grzegorz Węgrzyn ◽  
...  
Keyword(s):  
Immune Response ◽  
Immune Responses ◽  
Immune Modulation ◽  
Host Cells ◽  
Eukaryotic Cells ◽  
Mammalian Host ◽  
Immune Functions ◽  
Human Immune Response ◽  
Human Immune ◽  
Biological Entities

Bacteriophages are natural biological entities that limit the growth and amplification of bacteria. They are important stimulators of evolutionary variability in bacteria, and currently are considered a weapon against antibiotic resistance of bacteria. Nevertheless, apart from their antibacterial activity, phages may act as modulators of mammalian immune responses. In this paper, we focus on temperate phages able to execute the lysogenic development, which may shape animal or human immune response by influencing various processes, including phagocytosis of bacterial invaders and immune modulation of mammalian host cells.

scholarly journals Staphylococcal Protein A Induces Leukocyte Necrosis by Complexing with Human Immunoglobulins

mBio ◽  
2021 ◽  
Author(s):  
Proinnsias G. Fox ◽  
Francesca Schiavetti ◽  
Rino Rappuoli ◽  
Rachel M. McLoughlin ◽  
Fabio Bagnoli
Keyword(s):  
Staphylococcus Aureus ◽  
Protein A ◽  
The United States ◽  
Staphylococcal Protein A ◽  
Human Pathogen ◽  
Content Type ◽  
Staphylococcal Protein ◽  
Human Immunoglobulins ◽  
Human Immune Response ◽  
Human Immune

Staphylococcus aureus is one of the largest health care threats faced by humankind, with a reported mortality rate within the United States greater than that of HIV/AIDS, tuberculosis, and viral hepatitis combined. One of the defining features of S. aureus as a human pathogen is its ability to evade and impair the human immune response through expression of staphylococcal protein A.

Identification of biologic agents to neutralize the bicomponent leukocidins of Staphylococcus aureus

2019 ◽  
Vol 11 (475) ◽  
pp. eaat0882 ◽  
Author(s):  
Rita Chan ◽  
Peter T. Buckley ◽  
Aidan O’Malley ◽  
William E. Sause ◽  
Francis Alonzo ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Virulence Factors ◽  
Immune Cells ◽  
Ex Vivo ◽  
Fibronectin Type Iii ◽  
Human Immune Response ◽  
Human Immune ◽  
Critical Components ◽  
Systemic Infections

A key aspect underlying the severity of infections caused by Staphylococcus aureus is the abundance of virulence factors that the pathogen uses to thwart critical components of the human immune response. One such mechanism involves the destruction of host immune cells by cytolytic toxins secreted by S. aureus, including five bicomponent leukocidins: PVL, HlgAB, HlgCB, LukED, and LukAB. Purified leukocidins can lyse immune cells ex vivo, and systemic injections of purified LukED or HlgAB can acutely kill mice. Here, we describe the generation and characterization of centyrins that bind S. aureus leukocidins with high affinity and protect primary human immune cells from toxin-mediated cytolysis. Centyrins are small protein scaffolds derived from the fibronectin type III–binding domain of the human protein tenascin-C. Although centyrins are potent in tissue culture assays, their short serum half-lives limit their efficacies in vivo. By extending the serum half-lives of centyrins through their fusion to an albumin-binding consensus domain, we demonstrate the in vivo efficacy of these biologics in a murine intoxication model and in models of both prophylactic and therapeutic treatment of live S. aureus systemic infections. These biologics that target S. aureus virulence factors have potential for treating and preventing serious staphylococcal infections.

scholarly journals Human Immune Response to COVID-19 Infection and Potential Role of Chloroquine Family of Drugs

2020 ◽  
Author(s):  
Sunita Singh ◽  
Chandra Shekharaiah PS ◽  
Vishal Paul ◽  
Santosh Kodgire ◽  
Shivbachan Kushwaha ◽  
...  
Keyword(s):  
Immune Response ◽  
Immune Responses ◽  
Clinical Studies ◽  
Task Force ◽  
The Body ◽  
European Medicines Agency ◽  
Regulatory Bodies ◽  
Human Immune Response ◽  
Human Immune ◽  
Set Up

Currently, world is witnessing a massive morbidity and mortality due to COVID-19 pandemic.  A novel strain of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is the causative agent of coronavirus disease 2019 (COVID-19). The virus enters inside the body and infect the cells through angiotensin-converting enzyme 2 (ACE2) receptor. The S1 protein of SARS-CoV-2 binds to the ACE2 receptor which results in endocytosis and transfer of virus into endosomes of body cells. Entry of SARS-CoV-2 results in activation of innate immune responses first followed by adaptive immune responses. The effective host immune responses are crucial to control and prevent viral infection. However, excessive production of proinflammatory cytokines and decrease in number of T-lymphocytes are the major reasons associated with severity of COVID-19. Therapies and drugs that can modulate the immune responses appropriately may play a crucial role to control and prevent the progression of disease. Chloroquine (CQ) and hydroxychloroquine (HCQ) have anti-inflammatory, immunomodulatory, antitumor, antimicrobial and antithrombotic effects. These drugs have already been registered in many countries to treat arthritis, lupus and malaria. The treatment responses of COVID-19 patients to these drugs have been found positive in some cases and clinical studies are underway for evaluating these drugs for the same. However, there are some serious side effects and health hazards associated. Many regulatory bodies are demanding more conclusive data on efficacy and safety from the clinical studies. Moreover, some regulatory bodies such as Food and Drug Administration (FDA) and European Medicines Agency (EMA) have recommended to use these drugs in emergency and chronic situation to treat critically ill COVID-19 patients under doctor’s supervision with all issued guidelines. The national task force (NTF) set up by Indian Council of Medical Research has recommended high risk individuals to take HCQ for prophylaxis. This review summarizes human immune response and various aspects of CQ and HCQ with special reference to COVID-19.

scholarly journals Immune evasion by Staphylococcus aureus conferred by iron-regulated surface determinant protein IsdH

Microbiology ◽  
2009 ◽  
Vol 155 (3) ◽  
pp. 667-679 ◽  
Author(s):  
Livia Visai ◽  
Naoko Yanagisawa ◽  
Elisabet Josefsson ◽  
Andrej Tarkowski ◽  
Ilaria Pezzali ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Immune Responses ◽  
Innate Immune ◽  
Human Neutrophils ◽  
Protective Mechanism ◽  
Innate Immune Responses ◽  
Null Mutant ◽  
Wild Type ◽  
Accelerated Degradation ◽  
Associated Proteins

The ability of Staphylococcus aureus to avoid innate immune responses including neutrophil-mediated phagocytosis is crucial for the organism to cause infection. This multifactorial process involves several secreted and cell-surface-associated proteins. In this paper we report a novel mechanism of combating neutrophils that involves iron-regulated surface determinant protein H (IsdH). The IsdH protein is part of a complex that is only expressed under iron-restricted conditions in order to bind haemoglobin and extract and transport haem into the cytoplasm. A null mutant defective in expression of IsdH, and mutants expressing variants of IsdH with substitutions in residues predicted to be involved in ligand binding, were generated from S. aureus 8325-4. The IsdH-defective mutants were shown by several measures to have reduced virulence compared with the wild-type. The mutant was engulfed more rapidly by human neutrophils in the presence of serum opsonins, survived poorly in fresh whole human blood and was less virulent in a mouse model of sepsis. The protective mechanism seems to stem from an accelerated degradation of the serum opsonin C3b.

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