scholarly journals Testing Antigens, Antibodies, and Immune Cells in COVID-19 as a Public Health Topic—Experience and Outlines

2021 ◽  
Vol 18 (24) ◽  
pp. 13173
Author(s):  
Monica Neagu ◽  
Carolina Constantin ◽  
Mihaela Surcel
Keyword(s):  
Public Health ◽  
Immune Cells ◽  
Digital Pcr ◽  
Immune Memory ◽  
Diagnostic Strategies ◽  
Molecular Tests ◽  
Chemiluminescent Microparticle Immunoassay ◽  
Pcr Method ◽  
Antigen Testing ◽  
Research Domains

The current COVID-19 pandemic has triggered an accelerated pace in all research domains, including reliable diagnostics methodology. Molecular diagnostics of the virus and its presence in biological samples relies on the RT-PCR method, the most used and validated worldwide. Nonconventional tests with improved parameters that are in the development stages will be presented, such as droplet digital PCR or CRISPR-based assays. These molecular tests were followed by rapid antigen testing along with the development of antibody tests, whether based on ELISA platform or on a chemiluminescent microparticle immunoassay. Less-conventional methods of testing antibodies (e.g., lateral flow immunoassay) are presented as well. Left somewhere in the backstage of COVID-19 research, immune cells and, furthermore, immune memory cells, are gaining the spotlight, more so in the vaccination context. Recently, methodologies using flow-cytometry evaluate circulating immune cells in infected/recovered patients. The appearance of new virus variants has triggered a surge for tests improvement. As the pandemic has entered an ongoing or postvaccination era, all methodologies that are used to monitor public health focus on diagnostic strategies and this review points out where gaps should be filled in both clinical and research settings.

scholarly journals The Role of the Pathogen Dose and PI3Kγ in Immunometabolic Reprogramming of Microglia for Innate Immune Memory

2021 ◽  
Vol 22 (5) ◽  
pp. 2578
Author(s):  
Trim Lajqi ◽  
Christian Marx ◽  
Hannes Hudalla ◽  
Fabienne Haas ◽  
Silke Große ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Immune Tolerance ◽  
Immune Cells ◽  
Low Dose ◽  
Innate Immune ◽  
Immune Memory ◽  
Innate Immune Cells ◽  
Atp Production ◽  
Dose Dependent

Microglia, the innate immune cells of the CNS, exhibit long-term response changes indicative of innate immune memory (IIM). Our previous studies revealed IIM patterns of microglia with opposing immune phenotypes: trained immunity after a low dose and immune tolerance after a high dose challenge with pathogen-associated molecular patterns (PAMP). Compelling evidence shows that innate immune cells adopt features of IIM via immunometabolic control. However, immunometabolic reprogramming involved in the regulation of IIM in microglia has not been fully addressed. Here, we evaluated the impact of dose-dependent microglial priming with ultra-low (ULP, 1 fg/mL) and high (HP, 100 ng/mL) lipopolysaccharide (LPS) doses on immunometabolic rewiring. Furthermore, we addressed the role of PI3Kγ on immunometabolic control using naïve primary microglia derived from newborn wild-type mice, PI3Kγ-deficient mice and mice carrying a targeted mutation causing loss of lipid kinase activity. We found that ULP-induced IIM triggered an enhancement of oxygen consumption and ATP production. In contrast, HP was followed by suppressed oxygen consumption and glycolytic activity indicative of immune tolerance. PI3Kγ inhibited glycolysis due to modulation of cAMP-dependent pathways. However, no impact of specific PI3Kγ signaling on immunometabolic rewiring due to dose-dependent LPS priming was detected. In conclusion, immunometabolic reprogramming of microglia is involved in IIM in a dose-dependent manner via the glycolytic pathway, oxygen consumption and ATP production: ULP (ultra-low-dose priming) increases it, while HP reduces it.

scholarly journals The ZKIR Assay, a novel Real-Time PCR Method for the Detection of Klebsiella pneumoniae and Closely Related Species in Environmental Samples

2019 ◽  
Author(s):  
Elodie Barbier ◽  
Carla Rodrigues ◽  
Geraldine Depret ◽  
Virginie Passet ◽  
Laurent Gal ◽  
...  
Keyword(s):  
Public Health ◽  
Klebsiella Pneumoniae ◽  
Real Time ◽  
Real Time Pcr ◽  
Environmental Samples ◽  
Health Concern ◽  
Complex Matrices ◽  
Animal Pathogens ◽  
Novel Method ◽  
Pcr Method

ABSTRACTKlebsiella pneumoniae (Kp) is of growing public health concern due to the emergence of strains that are multidrug-resistant, virulent, or both. Taxonomically, Kp includes seven phylogroups, with Kp1 (K. pneumoniae sensu stricto) being medically prominent. Kp can be present in environmental sources such as soils and vegetation, which could act as reservoirs of animal and human infections. However, the current lack of screening methods to detect Kp in complex matrices limits research on Kp ecology. Here we analysed 4222 genome sequences and found that existing molecular detection targets lack specificity for Kp. A novel real-time PCR method, the ZKIR assay, was developed and used to detect Kp in 96 environmental samples. Results were compared to a culture-based method using SCAI agar medium coupled to MALDI-TOF mass spectrometry identification. Whole-genome sequencing of environmental Kp was performed. The ZKIR assay was positive for the 48 tested Kp reference strains, whereas 88 non-Kp strains were negative. The limit of detection of Kp in spiked soil microcosms was 1.5 × 10-1 CFU g-1 after enrichment for 24 h in LB supplemented with ampicillin, and 1.5 × 103 to 1.5 × 104 CFU g-1 directly after soil DNA extraction. The ZKIR assay was more sensitive than the culture method. Kp was detected in 43% of environmental samples. Genomic analysis of the isolates revealed a predominance of phylogroups Kp1 (65%) and Kp3 (32%), a high genetic diversity (23 MLST sequence types), a quasi-absence of antibiotic resistance or virulence genes, and a high frequency (50%) of O-antigen type 3. This study shows that the ZKIR assay is an accurate, specific and sensitive novel method to detect the presence of Kp in complex matrices, and indicates that Kp isolates from environmental samples differ from clinical isolates.IMPORTANCEThe Klebsiella pneumoniae species complex (Kp) includes human and animal pathogens, some of which are emerging as hypervirulent and/or antibiotic resistant strains. These pathogens are diverse and classified into seven phylogroups, which may differ in their reservoirs and epidemiology. Proper management of this public health hazard requires a better understanding of Kp ecology and routes of transmission to humans. So far, detection of these microorganisms in complex matrices such as food or the environment has been difficult due to a lack of accurate and sensitive methods. Here, we describe a novel method based on real-time PCR, which enables detection of all Kp phylogroups with high sensitivity and specificity. We used this method to detect Kp isolates from environmental samples, and show based on genomic sequencing that they differ in antimicrobial resistance and virulence gene content, from human clinical Kp isolates. The ZKIR PCR assay will enable rapid screening of multiple samples for Kp presence and will thereby facilitate tracking the dispersal patterns of these pathogenic strains across environmental, food, animal and human sources.

scholarly journals Hematopoietic Stem and Immune Cells in Chronic HIV Infection

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Jielin Zhang ◽  
Clyde Crumpacker
Keyword(s):  
Hiv Infection ◽  
Immune Cells ◽  
Memory Cell ◽  
Point Of View ◽  
Immune Memory ◽  
Self Renewal ◽  
Viral Pathogen ◽  
Hematopoietic Stem ◽  
Effector Cells ◽  
Chronic Hiv Infection

Hematopoietic stem cell (HSC) belongs to multipotent adult somatic stem cells. A single HSC can reconstitute the entire blood system via self-renewal, differentiation into all lineages of blood cells, and replenishment of cells lost due to attrition or disease in a person’s lifetime. Although all blood and immune cells derive from HSC, immune cells, specifically immune memory cells, have the properties of HSC on self-renewal and differentiation into lineage effector cells responding to the invading pathogens. Moreover, the interplay between immune memory cell and viral pathogen determines the course of a viral infection. Here, we state our point of view on the role of blood stem and progenitor cell in chronic HIV infection, with a focus on memory CD4 T-cell in the context of HIV/AIDS eradication and cure.

scholarly journals The ZKIR Assay, a Real-Time PCR Method for the Detection of Klebsiella pneumoniae and Closely Related Species in Environmental Samples

2020 ◽  
Vol 86 (7) ◽  
Author(s):  
Elodie Barbier ◽  
Carla Rodrigues ◽  
Geraldine Depret ◽  
Virginie Passet ◽  
Laurent Gal ◽  
...  
Keyword(s):  
Public Health ◽  
Klebsiella Pneumoniae ◽  
Real Time ◽  
Real Time Pcr ◽  
Environmental Samples ◽  
Health Concern ◽  
Complex Matrices ◽  
Content Type ◽  
Novel Method ◽  
Pcr Method

ABSTRACT Klebsiella pneumoniae is of growing public health concern due to the emergence of strains that are multidrug resistant, virulent, or both. Taxonomically, the K. pneumoniae complex (“Kp”) includes seven phylogroups, with Kp1 (K. pneumoniae sensu stricto) being medically prominent. Kp can be present in environmental sources such as soils and vegetation, which could act as reservoirs of animal and human infections. However, the current lack of screening methods to detect Kp in complex matrices limits research on Kp ecology. Here, we analyzed 1,001 genome sequences and found that existing molecular detection targets lack specificity for Kp. A novel real-time PCR method, the ZKIR (zur-khe intergenic region) assay, was developed and used to detect Kp in 96 environmental samples. The results were compared to a culture-based method using Simmons citrate agar with 1% inositol medium coupled to matrix-assisted laser desorption ionization–time of flight mass spectrometry identification. Whole-genome sequencing of environmental Kp was performed. The ZKIR assay was positive for the 48 tested Kp reference strains, whereas 88 non-Kp strains were negative. The limit of detection of Kp in spiked soil microcosms was 1.5 × 10−1 CFU g−1 after enrichment for 24 h in lysogeny broth supplemented with ampicillin, and it was 1.5 × 103 to 1.5 × 104 CFU g−1 directly after soil DNA extraction. The ZKIR assay was more sensitive than the culture method. Kp was detected in 43% of environmental samples. Genomic analysis of the isolates revealed a predominance of phylogroups Kp1 (65%) and Kp3 (32%), a high genetic diversity (23 multilocus sequence types), a quasi-absence of antibiotic resistance or virulence genes, and a high frequency (50%) of O-antigen type 3. This study shows that the ZKIR assay is an accurate, specific, and sensitive novel method to detect the presence of Kp in complex matrices and indicates that Kp isolates from environmental samples differ from clinical isolates. IMPORTANCE The Klebsiella pneumoniae species complex Kp includes human and animal pathogens, some of which are emerging as hypervirulent and/or antibiotic-resistant strains. These pathogens are diverse and classified into seven phylogroups, which may differ in their reservoirs and epidemiology. Proper management of this public health hazard requires a better understanding of Kp ecology and routes of transmission to humans. So far, detection of these microorganisms in complex matrices such as food or the environment has been difficult due to a lack of accurate and sensitive methods. Here, we describe a novel method based on real-time PCR which enables detection of all Kp phylogroups with high sensitivity and specificity. We used this method to detect Kp isolates from environmental samples, and we show based on genomic sequencing that they differ in antimicrobial resistance and virulence gene content from human clinical Kp isolates. The ZKIR PCR assay will enable rapid screening of multiple samples for Kp presence and will thereby facilitate tracking the dispersal patterns of these pathogenic strains across environmental, food, animal and human sources.

scholarly journals FINDINGS OF THE ANAPLASMA PHAGOCYTOPILUM GENOME IN TICKS FROM VOJVODINA AREA, SERBIA

2013 ◽  
Vol 6 (1) ◽  
pp. 29-43 ◽  
Author(s):  
Aleksandar Potkonjak ◽  
Sara Savić ◽  
Živoslav Grgić ◽  
Branislav Lako ◽  
Vuk Vračar ◽  
...  
Keyword(s):  
Public Health ◽  
Anaplasma Phagocytophilum ◽  
Human Population ◽  
Dermacentor Reticulatus ◽  
Wild Animals ◽  
Obligate Intracellular Bacterium ◽  
Gram Negative ◽  
Obligate Intracellular ◽  
Pcr Method ◽  
Autonomous Province

Ticks are vectors for many infectious diseases and represent a constant threat to human population and other animals, especially with respect to zoonoses. Th e cause of granulocyte anaplasmosis Anaplasma phagocytophilum is a gram-negative, obligate intracellular bacterium that infects people as well as various domestic and wild animals. Th e agent is spread worldwide, persisting in the natural environment through an enzootic circle between ticks and their hosting vertebrae. Th e aim of this paper is to demonstrate the distribution of ticks’ infection with Anaplasma phagocytophilum in the territory of the Autonomous Province of Vojvodina. Ticks were collected at ten locations in the Autonomous Province of Vojvodina, Serbia, which are a rural habitat for ticks. By applying the nested PCR method, the ticks were examined for the presence of specifi c DNA p44/msp2 Anaplasma phagocytphilum. Of the ten examined pools of ticks collected in the area of the Autonomous Province of Vojvodina, the presence of genome of the agent Anaplasma phagocytophilum was confi rmed in six pools applying the PCR method. In five pools of ticks of the species Ixodes ricinus, presence of agent Anaplasma phagocytophilum was confi rmed. Th ese ticks were found at the following locations: Poplar Research Institute (2 locations), Fruška gora (2 locations) Poloj-forest Bačka Palanka (1 location). In one pool of ticks of the species Dermacentor reticulatus from the location Poloj-forest Bačka Palanka, we confi rmed the presence of Anaplasma phagocytophilum genome. This infection can be a problem for public health, so further and more comprehensive acharological and epidemiological research is necessary in the Autonomous Province of Vojvodina.

scholarly journals Antigen Testing for COVID-19 Asymptomatic Screening: Why it Should be Preferred Over PCR Insights From Navy Region Japan’s Experience With a Comprehensive Antigen Testing Strategy

2021 ◽  
Author(s):  
Ross A Mullinax
Keyword(s):  
Public Health ◽  
Infectious Virus ◽  
Infectious Period ◽  
Test Results ◽  
Testing Strategy ◽  
Viral Loads ◽  
Viral Culture ◽  
Polymerase Chain ◽  
Antigen Testing

ABSTRACT Polymerase chain reaction (PCR) is commonly used in asymptomatic screening testing, but is suboptimal for this purpose as it will identify many old persistent positives that are no longer infectious. This can result in placement of individuals that are not infectious to others into isolation. This results in substantial adverse impact to military manning and operations, without any benefit to public health. Antigen testing does not have this same drawback. Antigen testing, while less sensitive than PCR, will identify the vast majority of infectious positives, especially those with higher viral loads that are more likely to transmit to others. Importantly, use of antigen testing will also greatly increase the certainty of benefit from isolation, reducing the risk of isolating those individuals who are beyond their infectious period and pose no threat to public health. The literature on this topic is reviewed, with particular focus on studies that perform viral culture in addition to PCR and antigen testing. This allows for determination of sensitivity for infectious virus. Also, Navy Region Japan’s experience with a comprehensive antigen testing strategy is described. The challenges presented by persistent positive PCR test results are examined, as well as the real-world benefits from implementing widespread use of antigen testing.

scholarly journals Evaluation of Large-Scale Rapid Antigen Testing of Incoming Passengers at a Dynamic Point of Care Setting Carried Out by Dental Students for Covid-19 Screening – A Field Report

2021 ◽  
Vol 10 (33) ◽  
pp. 2734-2739
Author(s):  
Akshay K. Langalia ◽  
Dolly P. Patel ◽  
Aravind D. Kumbhar ◽  
Hetal J. Maheshwari ◽  
Shubhangi K. Vyas ◽  
...  
Keyword(s):  
Large Scale ◽  
Point Of Care ◽  
Dental Students ◽  
Antigen Detection ◽  
Rapid Antigen Detection Test ◽  
Molecular Tests ◽  
Testing Facility ◽  
Field Report ◽  
Antigen Testing ◽  
Central Station

BACKGROUND Assessment of the results of large-scale rapid antigen diagnostic (RAD) testing for detection of SARS-CoV-2 amongst incoming passengers was carried out by Ahmedabad Municipal Corporation (AMC) Dental College Students at the Central Railway Station of Ahmedabad city. We wanted to determine the sensitivity and specificity of RAD testing for detection of Covid-19 amongst passengers disembarking from scheduled trains arriving at the Central Railway Terminus of Ahmedabad city. METHODS Under the campaign “Chase the Virus” launched by Ahmedabad Municipal Corporation (AMC), Interns & Final Year students of AMC Dental College were trained to carry out rapid antigen testing of scheduled trains running on special routes starting from 07 / 09 / 2020 to 05 / 10 / 2020. 14 dental teams were deputed at a temporary testing facility formulated for day-to-day testing at the Central Station using the standalone Standard - Q Covid-19 Ag testing kit (SD Biosensor, South Korea). RESULTS In total, 18901 travellers were tested in a span of 26 days out of which 324 tested positive with an overall percentage positivity of 1.71 %. An average number of 727 (± 182) tests were performed with an overall sensitivity of 66.01 % and specificity of 99.71 %. CONCLUSIONS In response to the growing Covid-19 pandemic and complexity of laboratory-based molecular tests, rapid antigen detection tests have proved to be efficient in the easier and faster diagnosis of the passengers in such point of care settings. KEY WORDS Rapid Antigen Detection Test, Covid-19, SARS-CoV-2

scholarly journals Implementation of Rapid and Frequent SARS-CoV2 Antigen Testing and Response in Congregate Homeless Shelters

2021 ◽  
Author(s):  
Andrés Aranda-Díaz ◽  
Elizabeth Imbert ◽  
Sarah Strieff ◽  
Dave Graham-Squire ◽  
Jennifer L Evans ◽  
...  
Keyword(s):  
Public Health ◽  
High Risk ◽  
San Francisco ◽  
Viable Alternative ◽  
Homeless Shelters ◽  
Minimal Support ◽  
Antigen Testing ◽  
Current Screening

AbstractBackgroundPeople experiencing homelessness who live in congregate shelters are at high risk of SARS-CoV2 transmission and severe COVID-19. Current screening and response protocols using rRT-PCR in homeless shelters are expensive, require specialized staff and have delays in returning results and implementing responses.MethodsWe piloted a program to offer frequent, rapid antigen-based tests (BinaxNOW) to residents and staff of congregate-living shelters in San Francisco, California, from January 15th to February 19th, 2021. We used the Reach-Effectiveness-Adoption-Implementation-Maintenance (RE-AIM) framework to evaluate the implementation.ResultsReachWe offered testing at ten of twelve eligible shelters. Shelter residents and staff had variable participation across shelters; approximately half of eligible individuals tested at least once; few tested consistently during the study.Effectiveness2.2% of participants tested positive. We identified three outbreaks, but none exceeded 5 cases. All BinaxNOW-positive participants were isolated or left the shelters.AdoptionWe offered testing to all eligible participants within weeks of the project’s initiation.ImplementationAdaptations made to increase reach and improve consistency were promptly implemented.MaintenanceSan Francisco Department of Public Health expanded and maintained testing with minimal support after the end of the pilot.ConclusionRapid and frequent antigen testing for SARS-CoV2 in homeless shelters is a viable alternative to rRT-PCR testing that can lead to immediate isolation of infectious individuals. Using the RE-AIM framework, we evaluated and adapted interventions to enable the expansion and maintenance of protocols.

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