scholarly journals Bacterial Keratitis Infection: A Battle Between Virulence Factors and the Immune Response

10.5772/52264 ◽  
2013 ◽  
Author(s):  
Atzin Robles-Contreras ◽  
Hector Javier ◽  
Alejandro Babayan Sosa ◽  
Oscar Baca-Loz
Keyword(s):  
Immune Response ◽  
Virulence Factors ◽  
Bacterial Keratitis

scholarly journals Protein Kinase G Induces an Immune Response in Cows Exposed toMycobacterium aviumSubsp.paratuberculosis

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Horacio Bach ◽  
Melissa Richard-Greenblatt ◽  
Eviatar Bach ◽  
Marcelo Chaffer ◽  
Wanika Lai ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Immune Response ◽  
Protein Kinase ◽  
Virulence Factors ◽  
Interferon Gamma ◽  
Host Cells ◽  
Protein Kinase G ◽  
Signal Transduction Pathways ◽  
Mycobacterial Species ◽  
Stimulation Of

To establish infection, pathogens secrete virulence factors, such as protein kinases and phosphatases, to modulate the signal transduction pathways used by host cells to initiate immune response. The protein MAP3893c is annotated in the genome sequence ofMycobacterium aviumsubspeciesparatuberculosis(MAP), the causative agent of Johne’s disease, as the serine/threonine protein kinase G (PknG). In this work, we report that PknG is a functional kinase that is secreted within macrophages at early stages of infection. The antigen is able to induce an immune response from cattle exposed to MAP in the form of interferon gamma production after stimulation of whole blood with PknG. These findings suggest that PknG may contribute to the pathogenesis of MAP by phosphorylating macrophage signalling and/or adaptor molecules as observed with other pathogenic mycobacterial species.

scholarly journals Proteases fromEntamoebaspp. and Pathogenic Free-Living Amoebae as Virulence Factors

2013 ◽  
Vol 2013 ◽  
pp. 1-32 ◽  
Author(s):  
Jesús Serrano-Luna ◽  
Carolina Piña-Vázquez ◽  
Magda Reyes-López ◽  
Guillermo Ortiz-Estrada ◽  
Mireya de la Garza
Keyword(s):  
Immune Response ◽  
Extracellular Matrix ◽  
Virulence Factors ◽  
Free Living ◽  
Highly Pathogenic ◽  
Cytopathic Effects ◽  
Human Parasite ◽  
System Components ◽  
Protease Expression ◽  
Specific Inhibitors

The standard reference for pathogenic and nonpathogenic amoebae is the human parasiteEntamoeba histolytica; a direct correlation between virulence and protease expression has been demonstrated for this amoeba. Traditionally, proteases are considered virulence factors, including those that produce cytopathic effects in the host or that have been implicated in manipulating the immune response. Here, we expand the scope to other amoebae, including less-pathogenicEntamoebaspecies and highly pathogenic free-living amoebae. In this paper, proteases that affect mucin, extracellular matrix, immune system components, and diverse tissues and cells are included, based on studies in amoebic cultures and animal models. We also include proteases used by amoebae to degrade iron-containing proteins because iron scavenger capacity is currently considered a virulence factor for pathogens. In addition, proteases that have a role in adhesion and encystation, which are essential for establishing and transmitting infection, are discussed. The study of proteases and their specific inhibitors is relevant to the search for new therapeutic targets and to increase the power of drugs used to treat the diseases caused by these complex microorganisms.

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 The immune response in Acinetobacter baumannii pneumonia

2016 ◽  
Vol 19 (1) ◽  
pp. 16-21 ◽  
Author(s):  
Cristina Anca Tudor ◽  
◽  
Cristian Boros ◽  
Raluca Petre ◽  
Adriana Elena Nica ◽  
...  
Keyword(s):  
Immune Response ◽  
Respiratory Tract ◽  
Acinetobacter Baumannii ◽  
Virulence Factors ◽  
Biofilm Formation ◽  
Lower Respiratory Tract ◽  
Defense Mechanism ◽  
Immunocompromised Patients ◽  
Common Site ◽  
Acinetobacter Baumanii

Acinetobacter baumannii is a bacterium that is commonly causes of nosocomial infections, the most common site of infection and colonization is the lower respiratory tract. Although it is present more often in immunocompromised patients, the defense mechanism against infection with Acinetobacter baumanii remains incomplete elucidated. Among the virulence factors involved in infection with Acinetobacter baumanii are production and release of exopolysaccharide, and ability to biofilm formation in tissues. Understanding of virulence mechanisms is important for early initiation of treatment.

scholarly journals Staphylococcus pseudintermedius, both commensal and pathogen

2018 ◽  
Vol 74 (1) ◽  
pp. 6042-2018
Author(s):  
Dorota Chrobak-Chmiel ◽  
Anna Golke ◽  
Kourou Dembele ◽  
Katarzyna Ćwiek ◽  
Magdalena Kizerwetter-Świda ◽  
...  
Keyword(s):  
Immune Response ◽  
Atopic Dermatitis ◽  
Immune System ◽  
Virulence Factors ◽  
Innate Immune Response ◽  
Innate Immune ◽  
Staphylococcus Pseudintermedius ◽  
Underlying Condition ◽  
Secondary Infections ◽  
Pathogenic Effects

Staphylococcus pseudintermedius is considered to be a both commensal and opportunistic canine pathogen. The anal, perineal and nasal locations appear to be the main S. pseudintermedius colonization sites, from which bacteria are transmitted to other body sites, causing secondary infections. When the immune system is compromised because of an underlying condition, the skin becomes susceptible to infection. Thus, the host’s condition seems to play a crucial role in the pathogenesis of S. pseudintermedius infections. There are some predisposing factors, one of which is atopic dermatitis. The pathogenic effects of S. pseudintermedius are mediated by several virulence factors, for instance superantigens, which play an important role by causing dermatitis. The immune system has evolved many different mechanisms to recognize and deal with pathogens, but bacteria have also developed various strategies to evade them. In this review, we focus on early stages of the innate immune response with particular emphasis on the mechanisms of recognition of staphylococci and the action of antimicrobial peptides. .

scholarly journals Oral Candidiasis: A Disease of Opportunity

2020 ◽  
Vol 6 (1) ◽  
pp. 15 ◽  
Author(s):  
Taissa Vila ◽  
Ahmed S. Sultan ◽  
Daniel Montelongo-Jauregui ◽  
Mary Ann Jabra-Rizk
Keyword(s):  
Immune Response ◽  
Oral Cavity ◽  
Oral Mucosa ◽  
Virulence Factors ◽  
Proteolytic Enzymes ◽  
Oral Candidiasis ◽  
Host Susceptibility ◽  
Initial Growth ◽  
Denture Stomatitis ◽  
Wide Range

Oral candidiasis, commonly referred to as “thrush,” is an opportunistic fungal infection that commonly affects the oral mucosa. The main causative agent, Candida albicans, is a highly versatile commensal organism that is well adapted to its human host; however, changes in the host microenvironment can promote the transition from one of commensalism to pathogen. This transition is heavily reliant on an impressive repertoire of virulence factors, most notably cell surface adhesins, proteolytic enzymes, morphologic switching, and the development of drug resistance. In the oral cavity, the co-adhesion of C. albicans with bacteria is crucial for its persistence, and a wide range of synergistic interactions with various oral species were described to enhance colonization in the host. As a frequent colonizer of the oral mucosa, the host immune response in the oral cavity is oriented toward a more tolerogenic state and, therefore, local innate immune defenses play a central role in maintaining Candida in its commensal state. Specifically, in addition to preventing Candida adherence to epithelial cells, saliva is enriched with anti-candidal peptides, considered to be part of the host innate immunity. The T helper 17 (Th17)-type adaptive immune response is mainly involved in mucosal host defenses, controlling initial growth of Candida and inhibiting subsequent tissue invasion. Animal models, most notably the mouse model of oropharyngeal candidiasis and the rat model of denture stomatitis, are instrumental in our understanding of Candida virulence factors and the factors leading to host susceptibility to infections. Given the continuing rise in development of resistance to the limited number of traditional antifungal agents, novel therapeutic strategies are directed toward identifying bioactive compounds that target pathogenic mechanisms to prevent C. albicans transition from harmless commensal to pathogen.

scholarly journals A microfluidic-based genetic screen to identify microbial virulence factors that inhibit dendritic cell migration

2014 ◽  
Vol 6 (4) ◽  
pp. 438-449 ◽  
Author(s):  
Laura M. McLaughlin ◽  
Hui Xu ◽  
Sarah E. Carden ◽  
Samantha Fisher ◽  
Monique Reyes ◽  
...  
Keyword(s):  
Immune Response ◽  
Cell Migration ◽  
Dendritic Cell ◽  
Virulence Factors ◽  
Genetic Screen ◽  
Critical Step ◽  
Dendritic Cell Migration ◽  
Human Immune Response ◽  
Human Immune ◽  
Cell Chemotaxis

A microfluidic-based screen to identify Salmonella genes that impede dendritic cell chemotaxis, a critical step of the human immune response.

scholarly journals Tailoring the Immune Response via Customization of Pathogen Gene Expression

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Lisa M. Runco ◽  
Charles B. Stauft ◽  
J. Robert Coleman
Keyword(s):  
Gene Expression ◽  
Immune Response ◽  
Virulence Factors ◽  
Vaccine Development ◽  
Host Immunity ◽  
Bacterial Disease ◽  
Amino Acid Residues ◽  
Bacterial Strains ◽  
Memory Response

The majority of studies focused on the construction and reengineering of bacterial pathogens have mainly relied on the knocking out of virulence factors or deletion/mutation of amino acid residues to then observe the microbe’s phenotype and the resulting effect on the host immune response. These knockout bacterial strains have also been proposed as vaccines to combat bacterial disease. Theoretically, knockout strains would be unable to cause disease since their virulence factors have been removed, yet they could induce a protective memory response. While knockout strains have been valuable tools to discern the role of virulence factors in host immunity and bacterial pathogenesis, they have been unable to yield clinically relevant vaccines. The advent of synthetic biology and enhanced user-directed gene customization has altered this binary process of knockout, followed by observation. Recent studies have shown that a researcher can now tailor and customize a given microbe’s gene expression to produce a desired immune response. In this commentary, we highlight these studies as a new avenue for controlling the inflammatory response as well as vaccine development.

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