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 Repertoire of the Bacillus thuringiensis Virulence Factors Unrelated to Major Classes of Protein Toxins and Its Role in Specificity of Host-Pathogen Interactions

Toxins ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 347 ◽  
Author(s):  
Yury V. Malovichko ◽  
Anton A. Nizhnikov ◽  
Kirill S. Antonets
Keyword(s):  
Immune Response ◽  
Extracellular Matrix ◽  
Bacillus Thuringiensis ◽  
Stationary Phase ◽  
Host Range ◽  
Host Specificity ◽  
Virulence Factors ◽  
Soil Bacteria ◽  
Cytotoxic Effect ◽  
Protein Toxins

Bacillus thuringiensis (Bt) is a Gram-positive soil bacteria that infects invertebrates, predominantly of Arthropoda phylum. Due to its immense host range Bt has become a leading producer of biopesticides applied both in biotechnology and agriculture. Cytotoxic effect of Bt, as well as its host specificity, are commonly attributed either to proteinaceous crystal parasporal toxins (Cry and Cyt) produced by bacteria in a stationary phase or to soluble toxins of Vip and Sip families secreted by vegetative cells. At the same time, numerous non-toxin virulence factors of Bt have been discovered, including metalloproteases, chitinases, aminopolyol antibiotics and nucleotide-mimicking moieties. These agents act at each stage of the B. thuringiensis invasion and contribute to cytotoxic properties of Bt strains enhancing toxin activity, ensuring host immune response evasion and participating in extracellular matrix degeneration. In this review we attempt to classify Bt virulence factors unrelated to major groups of protein toxins and discuss their putative role in the establishment of Bt specificity to various groups of insects.

scholarly journals Human Coronaviruses: Counteracting the Damage by Storm

Viruses ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1457
Author(s):  
Dewald Schoeman ◽  
Burtram C. Fielding
Keyword(s):  
Immune Response ◽  
Severe Disease ◽  
Antiviral Agents ◽  
The Elderly ◽  
Highly Pathogenic ◽  
Vaccine Responses ◽  
Cell Mediated Immune Response ◽  
Inhibition Antibody ◽  
A Cell ◽  
Human Coronaviruses

Over the past 18 years, three highly pathogenic human (h) coronaviruses (CoVs) have caused severe outbreaks, the most recent causative agent, SARS-CoV-2, being the first to cause a pandemic. Although much progress has been made since the COVID-19 pandemic started, much about SARS-CoV-2 and its disease, COVID-19, is still poorly understood. The highly pathogenic hCoVs differ in some respects, but also share some similarities in clinical presentation, the risk factors associated with severe disease, and the characteristic immunopathology associated with the progression to severe disease. This review aims to highlight these overlapping aspects of the highly pathogenic hCoVs—SARS-CoV, MERS-CoV, and SARS-CoV-2—briefly discussing the importance of an appropriately regulated immune response; how the immune response to these highly pathogenic hCoVs might be dysregulated through interferon (IFN) inhibition, antibody-dependent enhancement (ADE), and long non-coding RNA (lncRNA); and how these could link to the ensuing cytokine storm. The treatment approaches to highly pathogenic hCoV infections are discussed and it is suggested that a greater focus be placed on T-cell vaccines that elicit a cell-mediated immune response, using rapamycin as a potential agent to improve vaccine responses in the elderly and obese, and the potential of stapled peptides as antiviral agents.

scholarly journals Long-term maternal effect on offspring immune response in song sparrows Melospiza melodia

2006 ◽  
Vol 2 (4) ◽  
pp. 573-576 ◽  
Author(s):  
Jane M Reid ◽  
Peter Arcese ◽  
Lukas F Keller ◽  
Dennis Hasselquist
Keyword(s):  
Immune Response ◽  
Time Scales ◽  
Parasitic Infection ◽  
Antibody Responses ◽  
Melospiza Melodia ◽  
Long Term Effects ◽  
Free Living ◽  
Humoral Immune ◽  
Song Sparrows

Knowledge of the causes of variation in host immunity to parasitic infection and the time-scales over which variation persists, is integral to predicting the evolutionary and epidemiological consequences of host–parasite interactions. It is clear that offspring immunity can be influenced by parental immune experience, for example, reflecting transfer of antibodies from mothers to young offspring. However, it is less clear whether such parental effects persist or have functional consequences over longer time-scales, linking a parent's previous immune experience to future immune responsiveness in fully grown offspring. We used free-living song sparrows ( Melospiza melodia ) to quantify long-term effects of parental immune experience on offspring immune response. We experimentally vaccinated parents with a novel antigen and tested whether parental vaccination influenced the humoral antibody response mounted by fully grown offspring hatched the following year. Parental vaccination did not influence offspring baseline antibody titres. However, offspring of vaccinated mothers mounted substantially stronger antibody responses than offspring of unvaccinated mothers. Antibody responses did not differ between offspring of vaccinated and unvaccinated fathers. These data demonstrate substantial long-term effects of maternal immune experience on the humoral immune response of fully grown offspring in free-living birds.

scholarly journals Plasma vitronectin is reduced in patients with myasthenia gravis: Diagnostic and pathophysiological potential

2019 ◽  
Vol 8 ◽  
pp. 184945441987591 ◽  
Author(s):  
Antonio Junior Lepedda ◽  
Giovanni Andrea Deiana ◽  
Omar Lobina ◽  
Gabriele Nieddu ◽  
Paola Baldinu ◽  
...  
Keyword(s):  
Immune Response ◽  
Extracellular Matrix ◽  
Myasthenia Gravis ◽  
Cell Attachment ◽  
Postsynaptic Membrane ◽  
Clinical Value ◽  
Disease Biomarkers ◽  
Skeletal Muscle Weakness ◽  
Plasma Fractions ◽  
Muscle Specific Kinase

Myasthenia gravis (MG) is an autoimmune disease leading to varying degrees of skeletal muscle weakness. It is caused by specific antibodies directed against definite components in the postsynaptic membrane at the neuromuscular junction (NMJ), such as the acetylcholine receptor (AChR) and the muscle-specific kinase (MUSK) receptor. In clinical practice, MG patients may be classified into three main subgroups based on the occurrence of serum autoantibodies directed against AChR or MUSK receptor or antibody-negative. As the MG subgroups differ in terms of clinical characteristics, disease pathogenesis, prognosis, and response to therapies, they could benefit from targeted treatment as well as the detection of other possible disease biomarkers. We performed proteomics on plasma fractions enriched in low-abundance proteins to identify potential biomarkers according to different autoimmune responses. By this approach, we evidenced a significant reduction of vitronectin in MG patients compared to healthy controls, irrespective of the autoantibodies NMJ target. The obtained results were validated by mono- and two-dimensional Western blotting analysis. Vitronectin is a multifunctional glycoprotein involved in the regulation of several pathophysiological processes, including complement-dependent immune response, coagulation, fibrinolysis, pericellular proteolysis, cell attachment, and spreading. The pathophysiological significance of the reduction of plasma vitronectin in MG patients has yet to be fully elucidated. It could be related either to a possible deposition of vitronectin at NMJ to counteract the complement-mediated muscle damage at this level or to a parallel variation of this glycoprotein in the muscle extracellular matrix with secondary induced alteration in clustering of AChRs at NMJ, as it occurs with variation in concentrations of agrin, another extracellular matrix component. The clinical value of measuring plasma vitronectin has yet to be defined. According to present findings, significantly lower plasma values of this glycoprotein might be indicative of an impaired complement-dependent immune response.

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
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