scholarly journals Immune System Evasion Mechanisms in Staphylococcus aureus: Current Understanding

2020 ◽  
Vol 14 (4) ◽  
pp. 2219-2234
Author(s):  
Hesham A. Malak ◽  
Hussein H. Abulreesh ◽  
Sameer R. Organji ◽  
Khaled Elbanna ◽  
Mohammed R. Shaaban ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Immune System ◽  
Soft Tissue ◽  
Immune Cells ◽  
Bloodstream Infections ◽  
Host Cells ◽  
Human Pathogen ◽  
Immune Systems ◽  
Wide Range ◽  
New Strategy

Staphylococcus aureus is a major human pathogen that may cause a wide range of infections and is a frequent cause of soft tissue and bloodstream infections. It is a successful pathogen due to its collective virulence factors and its ability to evade the host immune systems. The review aims to highlight how S. aureus destroys and damage the host cells and explains how immune cells can respond to this pathogen. This review may also provide new insights that may be useful for developing new strategy for combating MRSA and its emerging clones such as community-associated methicillin-resistant S. aureus (CA-MRSA).

scholarly journals Complement Inactivation Strategy of Staphylococcus aureus Using Decay-Accelerating Factor and the Response of Infected HaCaT Cells

2021 ◽  
Vol 22 (8) ◽  
pp. 4015
Author(s):  
Kyoung Ok Jang ◽  
Youn Woo Lee ◽  
Hangeun Kim ◽  
Dae Kyun Chung
Keyword(s):  
Staphylococcus Aureus ◽  
Immune Cells ◽  
Respiratory Infections ◽  
Food Poisoning ◽  
Surface Expression ◽  
Host Cells ◽  
Hacat Cells ◽  
Decay Accelerating Factor ◽  
Ligand Expression ◽  
The Complement System

Staphylococcus aureus is a species of Gram-positive staphylococcus. It can cause sinusitis, respiratory infections, skin infections, and food poisoning. Recently, it was discovered that S. aureus infects epithelial cells, but the interaction between S. aureus and the host is not well known. In this study, we confirmed S. aureus to be internalized by HaCaT cells using the ESAT-6-like protein EsxB and amplified within the host over time by escaping host immunity. S. aureus increases the expression of decay-accelerating factor (CD55) on the surfaces of host cells, which inhibits the activation of the complement system. This mechanism makes it possible for S. aureus to survive in host cells. S. aureus, sufficiently amplified within the host, is released through the initiation of cell death. On the other hand, the infected host cells increase their surface expression of UL16 binding protein 1 to inform immune cells that they are infected and try to be eliminated. These host defense systems seem to involve the alteration of tight junctions and the induction of ligand expression to activate immune cells. Taken together, our study elucidates a novel aspect of the mechanisms of infection and immune system evasion for S. aureus.

scholarly journals Search for receptors in immune cells that bind cancer cell antigens and their activation in silent cases

2019 ◽  
Author(s):  
Wenfa Ng
Keyword(s):  
Immune System ◽  
Amino Acid ◽  
Cancer Cells ◽  
Cell Lines ◽  
Cancer Cell ◽  
Immune Cells ◽  
Immune Cell ◽  
Checkpoint Inhibitors ◽  
Host Cells ◽  
Immune Receptor

The immune checkpoint plays an important role in keeping immune cells in check for protecting tissues and organs from attack by the body’s own immune system. Similar concepts also apply in how cancer cells managed to fool immune cells through the surface display of particular antigens that mimic those exhibited by normal body cells. Specifically, cancer cells display antigens that bind to receptors on immune cells that subsequently prevent an attack on the cancer cells. Such binding between cancer antigens and immune cell receptors can be prevented through the use of checkpoint inhibitors antibodies specific for particular receptors on immune cells; thereby, unleashing immune cells to mount an immune response against cancer cells. While demonstrating good remissions in many patients where tumours shrunk substantially after administration of checkpoint inhibitors, cases exist where an overactivated immune system cause harm to organs and tissues culminating in multiple organ failure. Analysis of such toxicity effects of checkpoint inhibitors revealed that generic nature of targeted immune receptor plays a pivotal role in determining extent of side effects. Specifically, if the target immune receptor participates in checkpoints that prevent immune cells from attacking host cells, unleashing such receptors in cancer therapy may have untoward effects on patient’s health. Hence, the goal should be the selection of immune cell receptor specific to cancer cell antigens and which does not bind antigens or ligands displayed by the body’s cells. Such receptors would provide ideal targets for the development of checkpoint inhibitor antibodies for unleashing immune cells against cancer cells. To search for non-generic receptors that bind cancer cell antigens only, a combined computational and experimental approach could be used where ensemble of surface antigens on cancer cells and available receptors on immune cells could be profiled by biochemical assays. Downstream purification of ligands and receptors would provide for both structural elucidation and amino acid sequencing useful for bioinformatic search of homologous sequences. Knowledge of the antigens’ and receptors’ structures and amino acid sequence would subsequently serve as inputs to computational algorithms that models molecular docking events between receptor and antigen. This paves the way for heterologous expression of putative ligand and receptor in cell lines cultured in co-culture format for assessing binding between ligand and receptor, and more importantly, its physiological effects. Ability of immune receptor to bind to ligands on normal cells could also be assessed. Similar co-culture studies could be conducted with cancer cells and different immune cell types to check for reproducibility of observed effect in cell lines. Finally, antibodies could be raised for candidate receptors whose inhibition would not result in systemic attack of immune cells on host cells.

ROS-Sensitive Micelles for Controlled Delivery of Antibiotics to Combat Intracellular Staphylococcus aureus-Associated Infections

2021 ◽  
Author(s):  
Jing Qiao ◽  
Shuolin Cui ◽  
May Xiong
Keyword(s):  
Staphylococcus Aureus ◽  
Immune System ◽  
Controlled Delivery ◽  
Host Cells ◽  
Bactericidal Action

Bacteria can evade the immune system once they are engulfed by phagocytic host cells. This protects them against the bactericidal action of antibiotics and allows the infection to remain latent...

scholarly journals Rapid Detection of Methicillin-Resistant Staphylococcus aureus Directly from Blood for the Diagnosis of Bloodstream Infections: A Mini-Review

Diagnostics ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 830
Author(s):  
Anna Rita Buonomini ◽  
Elisabetta Riva ◽  
Giovanni Di Bonaventura ◽  
Giovanni Gherardi
Keyword(s):  
Staphylococcus Aureus ◽  
Gold Standard ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Bloodstream Infections ◽  
Rapid Diagnostic Tests ◽  
Blood Cultures ◽  
High Morbidity ◽  
Human Pathogen ◽  
Gold Standard Method ◽  
Methicillin Resistant

Staphylococcus aureus represents a major human pathogen able to cause a number of infections, especially bloodstream infections (BSI). Clinical use of methicillin has led to the emergence of methicillin-resistant S. aureus (MRSA) and MRSA-BSI have been reported to be associated with high morbidity and mortality. Clinical diagnosis of BSI is based on the results from blood culture that, although considered the gold standard method, is time-consuming. For this reason, rapid diagnostic tests to identify the presence of methicillin-susceptible S. aureus (MSSA) and MRSA isolates directly in blood cultures are being used with increasing frequency to rapidly commence targeted antimicrobial therapy, also in the light of antimicrobial stewardship efforts. Here, we review and report the most common rapid non-molecular and molecular methods currently available to detect the presence of MRSA directly from blood.

scholarly journals Extracellular Vesicles Released by Leishmania: Impact on Disease Development and Immune System Cells

2021 ◽  
Author(s):  
Rogéria Cristina Zauli ◽  
Andrey Sladkevicius Vidal ◽  
Talita Vieira Dupin ◽  
Aline Correia Costa de Morais ◽  
Wagner Luiz Batista ◽  
...  
Keyword(s):  
Immune Response ◽  
Immune System ◽  
Extracellular Vesicles ◽  
Virulence Factors ◽  
Immune Cells ◽  
Diagnostic Tool ◽  
Experimental Models ◽  
Host Cells ◽  
Disease Development ◽  
Leishmania Spp

Leishmania spp. release extracellular vesicles (EVs) containing parasite molecules, including several antigens and virulence factors. These EVs can interact with the host cells, such as immune cells, contributing to the parasite–host relationship. Studies have demonstrated that Leishmania-EVs can promote infection in experimental models and modulate the immune response. Although the immunomodulatory effect has been demonstrated, Leishmania-EVs can deliver parasite antigens and therefore have the potential for use as a new diagnostic tool and development of new therapeutic and vaccine approaches. This review aims to bring significant advances in the field of extracellular vesicles and Leishmania, focusing on their role in the cells of the immune system.

scholarly journals Study of Staphylococcus aureus Biofilm Ability to Destroy Bone Matrix in Absences of Host Immunity

2020 ◽  
Author(s):  
ahmed Al Ghaithi ◽  
Sultan Al Mastari ◽  
John Husband ◽  
Mohammed al kindi ◽  
Atika Al Bimani
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Staphylococcus Aureus ◽  
Raman Spectroscopy ◽  
Immune System ◽  
Bone Resorption ◽  
Bone Quality ◽  
Host Cells ◽  
Immune System Activation ◽  
Scanning Electron

AbstractPurposeOsteomyelitis is an infectious bone process leading to bone necrosis and destruction. Published reports on pathogen biofilm thus far have focused on indirect bone resorption mediated by host cells and factors secondary to immune system activation. However, direct bone resorption due to biofilm pathogen has not been adequately studied yet. This study aims to investigate the effect of biofilm pathogen in ex-vivo human bones in the absence of the host immune response using Raman spectroscopy and Scanning electron microscopy.MethodsBone samples collected from patients who underwent knee replacement surgeries were inoculated with Staphylococcus aureus bacteria. Bacterial direct effects on the bone quality were then examined, at various time intervals, using Raman spectroscopy and scanning electron microscopy.ResultsRaman spectroscopy and scanning electron demonstrated the destruction of bone structure and drop in bone quality.ConclusionThis experiment shows the direct effect of bacteria on bone during osteomyelitis in addition to the recognised destruction caused by the host immune system.

scholarly journals Search for receptors in immune cells that bind cancer cell antigens and their activation in silent cases

2019 ◽  
Author(s):  
Wenfa Ng
Keyword(s):  
Immune System ◽  
Amino Acid ◽  
Cancer Cells ◽  
Cell Lines ◽  
Cancer Cell ◽  
Immune Cells ◽  
Immune Cell ◽  
Checkpoint Inhibitors ◽  
Host Cells ◽  
Immune Receptor

The immune checkpoint plays an important role in keeping immune cells in check for protecting tissues and organs from attack by the body’s own immune system. Similar concepts also apply in how cancer cells managed to fool immune cells through the surface display of particular antigens that mimic those exhibited by normal body cells. Specifically, cancer cells display antigens that bind to receptors on immune cells that subsequently prevent an attack on the cancer cells. Such binding between cancer antigens and immune cell receptors can be prevented through the use of checkpoint inhibitors antibodies specific for particular receptors on immune cells; thereby, unleashing immune cells to mount an immune response against cancer cells. While demonstrating good remissions in many patients where tumours shrunk substantially after administration of checkpoint inhibitors, cases exist where an overactivated immune system cause harm to organs and tissues culminating in multiple organ failure. Analysis of such toxicity effects of checkpoint inhibitors revealed that generic nature of targeted immune receptor plays a pivotal role in determining extent of side effects. Specifically, if the target immune receptor participates in checkpoints that prevent immune cells from attacking host cells, unleashing such receptors in cancer therapy may have untoward effects on patient’s health. Hence, the goal should be the selection of immune cell receptor specific to cancer cell antigens and which does not bind antigens or ligands displayed by the body’s cells. Such receptors would provide ideal targets for the development of checkpoint inhibitor antibodies for unleashing immune cells against cancer cells. To search for non-generic receptors that bind cancer cell antigens only, a combined computational and experimental approach could be used where ensemble of surface antigens on cancer cells and available receptors on immune cells could be profiled by biochemical assays. Downstream purification of ligands and receptors would provide for both structural elucidation and amino acid sequencing useful for bioinformatic search of homologous sequences. Knowledge of the antigens’ and receptors’ structures and amino acid sequence would subsequently serve as inputs to computational algorithms that models molecular docking events between receptor and antigen. This paves the way for heterologous expression of putative ligand and receptor in cell lines cultured in co-culture format for assessing binding between ligand and receptor, and more importantly, its physiological effects. Ability of immune receptor to bind to ligands on normal cells could also be assessed. Similar co-culture studies could be conducted with cancer cells and different immune cell types to check for reproducibility of observed effect in cell lines. Finally, antibodies could be raised for candidate receptors whose inhibition would not result in systemic attack of immune cells on host cells.

scholarly journals Whole-Genome Sequences of Staphylococcus aureus Isolates from Positive Blood Cultures

2021 ◽  
Vol 10 (43) ◽  
Author(s):  
Itidal Reslane ◽  
Margaret Sladek ◽  
Paul D. Fey ◽  
Baha Abdalhamid
Keyword(s):  
Staphylococcus Aureus ◽  
Soft Tissue ◽  
Draft Genome ◽  
Bloodstream Infections ◽  
Blood Cultures ◽  
Whole Genome ◽  
Soft Tissue Infections ◽  
Genome Sequences ◽  
Content Type ◽  
Clinical Strains

Staphylococcus aureus is a major cause of skin and soft tissue infections as well as bloodstream infections worldwide. Here, we report the draft genome sequences of 18 deidentified S. aureus clinical strains collected from positive blood cultures.

Interferons: role in cancer therapy

Immunotherapy ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 833-855 ◽  
Author(s):  
Mohadeseh Haji Abdolvahab ◽  
Behrad Darvishi ◽  
Mohammad Zarei ◽  
Keivan Majidzadeh-A ◽  
Leila Farahmand
Keyword(s):  
Immune System ◽  
Cancer Therapy ◽  
Immune Cells ◽  
Biological Function ◽  
Host Cells ◽  
Combination Therapies ◽  
Chronic Stimulation ◽  
Induce Resistance ◽  
Extreme Responses ◽  
Stimulation Of

Interferons (IFNs) are a group of signaling cytokines, secreted by host cells to induce protection against various disorders. IFNs can directly impact on tumor cells or indirectly induce the immune system to protect host cells. The expression levels of IFNs and its functions of are excellently modulated in a way to protect host cells from probable toxicities caused by extreme responses. The efficacy of anticancer therapies is correlated to IFNs signaling. Although IFN signaling is involved in induction of antitumor responses, chronic stimulation of the IFN signaling pathway can induce resistance to various antineoplasm therapies. Hence, IFNs are expressed by both cancer and immune cells, and modulate their biological function. Understanding this mechanism of action might be a key target of combination therapies.

scholarly journals Bacteremia caused by Comamonas testosteroni an unusual pathogen

2019 ◽  
Vol 11 (01) ◽  
pp. 087-090
Author(s):  
Shreekant Tiwari ◽  
Monalisah Nanda
Keyword(s):  
Infectious Agent ◽  
Bloodstream Infections ◽  
Opportunistic Pathogen ◽  
Routine Clinical Practice ◽  
Clinical Approach ◽  
Comamonas Testosteroni ◽  
Human Pathogen ◽  
Natural Habitats ◽  
Reservoir Water ◽  
Wide Range

Abstract Comamonas species are rare isolates in microbiology laboratories and have been infrequently reported as an infectious agent in routine clinical practice. They have a wide range of natural habitats including water, soil, and plants as well as from some hospital devices, such as intravenous lines and the reservoir water in the humidifiers of respiratory therapy equipment. Comamonas testosteroni is rarely recognized as a human pathogen. In spite of its uncommon human pathogenesis, there are few reports where it was reported as an aggressive opportunistic pathogen, and that was mostly related to Testosterone species. Herewith, we are reporting this pathogen from the blood of an immunocompetent female. The aim of this case report is to alert clinicians and laboratory physicians for the potential diagnosis and clinical approach of bloodstream infections caused by such unusual pathogens. This is the first documented case of bacteremia caused by C. testosteroni from India.

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