scholarly journals Immunity to Sda1 Protects against Infection by Sda1+ and Sda1− Serotypes of Group A Streptococcus

Vaccines ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 102
Author(s):  
Shuai Bi ◽  
Jie Wang ◽  
Meiyi Xu ◽  
Ning Li ◽  
Beinan Wang
Keyword(s):  
Protective Immunity ◽  
Vaccine Candidate ◽  
Group A Streptococcus ◽  
Protective Role ◽  
Gas Reservoir ◽  
Extracellular Traps ◽  
Mucosal Site ◽  
Group A ◽  
Potential Vaccine

Group A Streptococcus (GAS) causes a variety of diseases globally. The DNases in GAS promote GAS evasion of neutrophil killing by degrading neutrophil extracellular traps (NETs). Sda1 is a prophage-encoded DNase associated with virulent GAS strains. However, protective immunity against Sda1 has not been determined. In this study, we explored the potential of Sda1 as a vaccine candidate. Sda1 was used as a vaccine to immunize mice intranasally. The effect of anti-Sda1 IgG in neutralizing degradation of NETs was determined and the protective role of Sda1 was investigated with intranasal and systemic challenge models. Antigen-specific antibodies were induced in the sera and pharyngeal mucosal site after Sda1 immunization. The anti-Sda1 IgG efficiently prevented degradation of NETs by supernatant samples from different GAS serotypes with or without Sda1. Sda1 immunization promoted clearance of GAS from the nasopharynx independent of GAS serotypes but did not reduce lethality after systemic GAS challenge. Anti-Sda1 antibody can neutralize degradation of NETs by Sda1 and other phage-encoded DNases and decrease GAS colonization at the nasopharynx across serotypes. These results indicate that Sda1 can be a potential vaccine candidate for reduction in GAS reservoir and GAS tonsillitis-associated diseases.

scholarly journals Schistosoma mansoni egg-derived extracellular vesicles: A promising vaccine candidate against murine schistosomiasis

2021 ◽  
Vol 15 (10) ◽  
pp. e0009866
Author(s):  
Shereen F. Mossallam ◽  
Iman F. Abou-El-Naga ◽  
Amany Abdel Bary ◽  
Eman A. Elmorsy ◽  
Radwa G. Diab
Keyword(s):  
Schistosoma Mansoni ◽  
Extracellular Vesicles ◽  
Vaccine Candidate ◽  
Protective Efficacy ◽  
Protective Role ◽  
Immunological Parameters ◽  
Transmission Electron ◽  
Potential Vaccine ◽  
Protein Components

Extracellular vesicles (EVs) are protein-loaded nano-scaled particles that are extracellularly released by eukaryotes and prokaryotes. Parasite’s EVs manipulate the immune system, making them probable next-generation vaccines. Schistosomal EVs carry different proteins of promising immunizing potentials. For evaluating the immune-protective role of Schistosoma mansoni (S. mansoni) egg-derived EVs against murine schistosomiasis, EVs were isolated from cultured S. mansoni eggs by progressive sequential cooling ultra-centrifugation technique. Isolated EVs were structurally identified using transmission electron microscope and their protein was quantified by Lowry’s technique. Experimental mice were subcutaneously immunized with three doses of 20 μg EVs (with or without alum adjuvant); every two weeks, then were challenged with S. mansoni cercariae two weeks after the last immunizing dose. Six weeks post infection, mice were sacrificed for vaccine candidate assessment. EVs protective efficacy was evaluated through parasitological, histopathological, and immunological parameters. Results showed significant reduction of tegumentally deranged adult worms, hepatic and intestinal egg counts reduction by 46.58%, 93.14% and 93.17% respectively, accompanied by remarkable amelioration of sizes, numbers and histopathology of hepatic granulomata mediated by high interferon gamma (IFN γ) and antibody level. Using sera from vaccinated mice, the molecular weight of EVs’ protein components targeted by the antibody produced was recognized by western immunoblot. Results revealed two bands of ~ 14 KDa and ~ 21 KDa, proving that EVs are able to stimulate specific antibodies response. In conclusion, the present study highlighted the role of S. mansoni-egg derived EVs as a potential vaccine candidate against murine schistosomiasis mansoni.

Etiology, clinical presentation, laboratory diagnostics, pathogenesis of impetigo and treatment methods

2020 ◽  
pp. 64-70
Author(s):  
Anastasiya Laknitskaya
Keyword(s):  
Streptococcus Pyogenes ◽  
Skin Diseases ◽  
Group A Streptococcus ◽  
Antibiotic Sensitivity ◽  
Antioxidant Defense System ◽  
Laboratory Diagnostics ◽  
Treatment Methods ◽  
Group A ◽  
The Individual

Currently, one of the priority medical and social problems is the optimization of treatment methods for pyoderma associated with Streptococcus pyogenes — group A streptococcus (GAS). To date, the proportion of pyoderma, the etiological factor of which is Streptococcus pyogenes, is about 6 % of all skin diseases and is in the range from 17.9 to 43.9 % of all dermatoses. Role of the bacterial factor in the development of streptococcal pyoderma is obvious. Traditional treatment complex includes antibacterial drugs selected individually, taking into account the antibiotic sensitivity of pathognomonic bacteria, and it is not always effective. Currently implemented immunocorrection methods often do not take into account specific immunological features of the disease, the individual, and the fact that the skin performs the function of not only a mechanical barrier, but it is also an immunocompetent organ. Such an approach makes it necessary to conduct additional studies clarifying the role of factors of innate and adaptive immunity, intercellular mediators and antioxidant defense system, that allow to optimize the treatment of this pathology.

scholarly journals Invasive Group A Streptococcal Disease in The Netherlands: Evidence for a Protective Role of Anti–Exotoxin A Antibodies

2000 ◽  
Vol 181 (2) ◽  
pp. 631-638 ◽  
Author(s):  
Ellen M. Mascini ◽  
Margriet Jansze ◽  
Joop F. P. Schellekens ◽  
James M. Musser ◽  
Joop A. J. Faber ◽  
...  
Keyword(s):  
The Netherlands ◽  
Protective Role ◽  
Exotoxin A ◽  
Invasive Group ◽  
Streptococcal Disease ◽  
Group A

scholarly journals The Role of Wound Care in 2 Group A Streptococcal Outbreaks in a Chicago Skilled Nursing Facility, 2015‒2016

2018 ◽  
Vol 5 (7) ◽  
Author(s):  
Sana S Ahmed ◽  
Kasey E Diebold ◽  
Jacob M Brandvold ◽  
Saadeh S Ewaidah ◽  
Stephanie Black ◽  
...  
Keyword(s):  
Group A Streptococcus ◽  
Wound Care ◽  
Skilled Nursing Facility ◽  
Prevention Measures ◽  
Nursing Facility ◽  
Skilled Nursing ◽  
Group A ◽  
Care Practices ◽  
Transmission Factors

Abstract Two consecutive outbreaks of group A Streptococcus (GAS) infections occurred from 2015–2016 among residents of a Chicago skilled nursing facility. Evaluation of wound care practices proved crucial for identifying transmission factors and implementing prevention measures. We demonstrated shedding of GAS on settle plates during care of a colonized wound.

scholarly journals Evaluation of safety and immunogenicity of a group A streptococcus vaccine candidate (MJ8VAX) in a randomized clinical trial

PLoS ONE ◽  
2018 ◽  
Vol 13 (7) ◽  
pp. e0198658 ◽  
Author(s):  
Silvana Sekuloski ◽  
Michael R. Batzloff ◽  
Paul Griffin ◽  
William Parsonage ◽  
Suzanne Elliott ◽  
...  
Keyword(s):  
Clinical Trial ◽  
Randomized Clinical Trial ◽  
Vaccine Candidate ◽  
Group A Streptococcus ◽  
Group A

Group A Streptococcus Carriage in an Alabama Child-Care Center Following a Fatal Invasive Case

PEDIATRICS ◽  
1994 ◽  
Vol 94 (6) ◽  
pp. 1030-1030
Author(s):  
Michael M. Engelgau ◽  
John M. Horan ◽  
Charles H. Woernle ◽  
Banjamin Schwartz ◽  
Richard R. Facklam ◽  
...  
Keyword(s):  
Risk Factors ◽  
Child Care ◽  
Group A Streptococcus ◽  
Care Center ◽  
Fatal Case ◽  
Prophylactic Antibiotic ◽  
Child Care Center ◽  
Antibiotic Administration ◽  
Group A

Carriage of the GAS strain was common and widespread following a single fatal case of invasive GAS disease at the child-care center. Risk factors for GAS T-1 carriage did not identify all carriers. Our findings suggest that widespread culturing is needed to identify all potential carriers. The role of prophylactic antibiotic administration in preventing secondary cases could not be determined.

scholarly journals Regulatory Role of GSK-3βon NF-κB, Nitric Oxide, and TNF-αin Group A Streptococcal Infection

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Yu-Tzu Chang ◽  
Chia-Ling Chen ◽  
Chiou-Feng Lin ◽  
Shiou-Ling Lu ◽  
Miao-Huei Cheng ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Mouse Model ◽  
Group A Streptococcus ◽  
Glycogen Synthase ◽  
Critical Issue ◽  
No Production ◽  
Group A ◽  
Oxide Synthase

Group A streptococcus (GAS) imposes a great burden on humans. Efforts to minimize the associated morbidity and mortality represent a critical issue. Glycogen synthase kinase-3β(GSK-3β) is known to regulate inflammatory response in infectious diseases. However, the regulation of GSK-3βin GAS infection is still unknown. The present study investigates the interaction between GSK-3β, NF-κB, and possible related inflammatory mediators in vitro and in a mouse model. The results revealed that GAS could activate NF-κB, followed by an increased expression of inducible nitric oxide synthase (iNOS) and NO production in a murine macrophage cell line. Activation of GSK-3βoccurred after GAS infection, and inhibition of GSK-3βreduced iNOS expression and NO production. Furthermore, GSK-3βinhibitors reduced NF-κB activation and subsequent TNF-αproduction, which indicates that GSK-3βacts upstream of NF-κB in GAS-infected macrophages. Similar to the in vitro findings, administration of GSK-3βinhibitor in an air pouch GAS infection mouse model significantly reduced the level of serum TNF-αand improved the survival rate. The inhibition of GSK-3βto moderate the inflammatory effect might be an alternative therapeutic strategy against GAS infection.

scholarly journals The Effect of a Mediterranean Meal on Sprague Dawley Rats DMBA-Induced Mammary Tumors

2010 ◽  
Vol 3 ◽  
pp. CGM.S5894
Author(s):  
Paula C. Pereira ◽  
A. Filipa Vicente ◽  
Maria F. Mesquita ◽  
Antonio S. Cabrita
Keyword(s):  
Experimental Studies ◽  
Protective Role ◽  
Female Rats ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Total Cancer ◽  
Group A ◽  
Histopathologic Analysis ◽  
Group B

The present study intents to find a possible protective role of a Mediterranean type meal on mammary carcinogenesis. Several factors have been associated with breast cancer risk, genetics and environment are the most pointed out in epidemiologic and experimental studies. Diet is an environmental factor that can promote or prevent disease, being responsible for almost 35% of total cancer cases. A total of 72 female rats 50 days old were randomly divided in three groups of 24 rats and housed 4 in each plastic cage in a holding room under constant conditions of 22 ± 2 °C, 55 ± 10% humidity and a 12 h light/dark cycle. All the animals were submitted to the administration of 20 mg of 7, 12 dimethylbenzanthracene (DMBA) in olive oil, by gavages, except group A. The same defined standard food was provided for all the animals in group A and B, supplemented with a Mediterranean meal in group C. All the animals were sacrificed by the end of 150 days. Total carcinoma number did not differ significantly between Groups B and C and there were not found any neoplastic lesions in Group A. Most tumors showed a mixed architectural pattern, with cribriform and papillary areas, comedocarcinoma and necrosis was only seen in Group B. Histopathologic analysis showed that Group C tumors had lower mitotic activity and Pattern Grades, but higher Nuclear Grades. Mediterranean diet type meal showed lower Pattern Grades and lower Mitotic count in spite of that a higher nuclear pleomorphism was also found. Even so, tumors from Group C were better differentiated which can indicate lower malignancy.

scholarly journals The Mga Regulon but Not Deoxyribonuclease Sda1 of Invasive M1T1 Group A Streptococcus Contributes toIn VivoSelection of CovRS Mutations and Resistance to Innate Immune Killing Mechanisms

2015 ◽  
Vol 83 (11) ◽  
pp. 4293-4303 ◽  
Author(s):  
Guanghui Liu ◽  
Wenchao Feng ◽  
Dengfeng Li ◽  
Mengyao Liu ◽  
Daniel C. Nelson ◽  
...  
Keyword(s):  
Group A Streptococcus ◽  
Regulatory System ◽  
Innate Immune ◽  
M Protein ◽  
Content Type ◽  
Group A ◽  
Innate Immune Evasion ◽  
Selection Of

ABSTRACTInvasive M1T1 group AStreptococcus(GAS) can have a mutation in the regulatory system CovRS, and this mutation can render strains hypervirulent. Interestingly, via mechanisms that are not well understood, the host innate immune system's neutrophils select spontaneous M1T1 GAS CovRS hypervirulent mutants, thereby enhancing the pathogen's ability to evade immune killing. It has been reported that the DNase Sda1 is critical for the resistance of M1T1 strain 5448 to killing in human blood and provides pressure forin vivoselection of CovRS mutations. We reexamined the role of Sda1 in the selection of CovRS mutations and in GAS innate immune evasion. Deletion ofsda1or all DNase genes in M1T1 strain MGAS2221 did not alter emergence of CovRS mutants during murine infection. Deletion ofsda1in strain 5448 resulted in Δsda1mutants with (5448 Δsda1M+strain) and without (5448 Δsda1M−strain) M protein production. The 5448 Δsda1M+strain accumulated CovRS mutationsin vivoand resisted killing in the bloodstream, whereas the 5448 Δsda1M−strain lostin vivoselection of CovRS mutations and was sensitive to killing. The deletion ofemmand a spontaneous Mga mutation in MGAS2221 reduced and preventedin vivoselection for CovRS mutants, respectively. Thus, in contrast to previous reports, Sda1 is not critical forin vivoselection of invasive M1T1 CovRS mutants and GAS resistance to innate immune killing mechanisms. In contrast, M protein and other Mga-regulated proteins contribute to thein vivoselection of M1T1 GAS CovRS mutants. These findings advance the understanding of the progression of invasive M1T1 GAS infections.

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