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SARS-CoV-2 herd immunity of the Kyrgyz population in 2021
AbstractIn the fight against coronavirus infection, control of the immune response is of decisive importance, an important component of which is the seroprevalence of antibodies to SARS-CoV-2. Immunity to SARS-CoV-2 is formed either naturally or artificially through vaccination. The purpose of this study was to assess the seroprevalence of antibodies to SARS-CoV-2 in the population of Kyrgyzstan. A cross-sectional randomized study of seroprevalence was carried out according to a program developed by Rospotrebnadzor and the St. Petersburg Pasteur Institute, taking into account WHO recommendations. The ethics committees of t...
Source: Medical Microbiology and Immunology - July 2, 2022 Category: Microbiology Source Type: research

Child type 1 diabetes associated with mother vaginal bacteriome and mycobiome
AbstractMother vaginal microbes contribute to microbiome of vaginally delivered neonates. Child microbiome can be associated with autoimmune diseases, such as type 1 diabetes (T1D). We collected vaginal DNA samples from 25 mothers with a vaginally delivered child diagnosed with T1D and samples from 24 control mothers who had vaginally delivered a healthy child and analyzed bacteriome and mycobiome of the samples. The total DNA of the samples was extracted, and ribosomal DNA regions (16S for bacteria, ITS2 for fungi) were amplified, followed by next-generation sequencing and machine learning. We found that alpha-diversity o...
Source: Medical Microbiology and Immunology - June 14, 2022 Category: Microbiology Source Type: research

Blood and saliva SARS-CoV-2 antibody levels in self-collected dried spot samples
We examined the usefulness of dried spot blood and saliva samples in SARS-CoV-2 antibody analyses. We analyzed 1231 self-collected dried spot blood and saliva samples from healthcare workers. Participants filled in a questionnaire on their COVID-19 exposures, infections, and vaccinations. Anti-SARS-CoV-2 IgG, IgA, and IgM levels were determined from both samples using the GSP/DELFIA method. The level of exposure was the strongest determinant of all blood antibody classes and saliva IgG, increasing as follows: (1) no exposure (healthy, non-vaccinated), (2) exposed, (3) former COVID-19 infection, (4) one vaccination, (5) two...
Source: Medical Microbiology and Immunology - June 13, 2022 Category: Microbiology Source Type: research

Mouse models in COVID-19 research: analyzing the adaptive immune response
AbstractThe emergence of SARS-CoV-2, the severe acute respiratory syndrome coronavirus type 2 causing the COVID-19 pandemic, resulted in a major necessity for scientific countermeasures. Investigations revealing the exact mechanisms of the SARS-CoV-2 pathogenesis provide the basis for the development of therapeutic measures and protective vaccines against COVID-19. Animal models are inevitable for infection and pre-clinical vaccination studies as well as therapeutic testing. A well-suited animal model, mimicking the pathology seen in human COVID-19 patients, is an important basis for these investigations. Several animal mo...
Source: Medical Microbiology and Immunology - June 4, 2022 Category: Microbiology Source Type: research

Genetic variability in minor capsid protein (L2 gene) of human papillomavirus type 16 among Indian women
AbstractHuman papillomavirus type 16 (HPV-16) is the predominant genotype worldwide associated with invasive cervical cancer and hence remains as the focus for diagnostic development and vaccine research. L2, the minor capsid protein forms the packaging unit for the HPV genome along with the L1 protein and is primarily associated with transport of genomic DNA to the nucleus. Unlike L1, L2 is known to elicit cross-neutralizing antibodies and thus becomes a suitable candidate for pan-HPV prophylactic vaccine development. In the present study, a total of 148 cervical HPV-16 isolates from Indian women were analyzed by PCR-dire...
Source: Medical Microbiology and Immunology - May 13, 2022 Category: Microbiology Source Type: research

Inflammatory cytokine profile and T cell responses in African tick bite fever patients
In this study, inflammatory mediators and T cell responses were examined in samples from 13 patients with polymerase chain reaction-confirmedR. africae infections at different time points of illness. The Th1-associated cytokines IFN γ and IL-12 were increased in the acute phase of illness, as were levels of the T cell chemoattractant cytokine CXCL-10. In addition, the anti-inflammatory cytokine IL-10 and also IL-22 were elevated. IL-22 but not IFNγ was increasingly produced by CD4+ and CD8+ T cells during illness. Besides IFN γ, IL-22 appears to play a protective role in rickettsial infections. (Source: Medical Microbiology and Immunology)
Source: Medical Microbiology and Immunology - May 11, 2022 Category: Microbiology Source Type: research

Cytokine responses of immunosuppressed and immunocompetent patients with Neoehrlichia mikurensis infection
ConclusionPro-angiogenic and type 1 cytokines were produced as part of the host response of neoehrlichiosis independent of immune status, whereas immunosuppressed neoehrlichiosis patients produced cytokines required for B cell-mediated defense. (Source: Medical Microbiology and Immunology)
Source: Medical Microbiology and Immunology - April 17, 2022 Category: Microbiology Source Type: research

Functional cross-species conservation of guanylate-binding proteins in innate immunity
AbstractGuanylate binding proteins (GBPs) represent an evolutionary ancient protein family widely distributed among eukaryotes. They are interferon (IFN)-inducible guanosine triphosphatases that belong to the dynamin superfamily. GBPs are known to have a major role in the cell-autonomous innate immune response against bacterial, parasitic and viral infections and are also involved in inflammasome activation. Evolutionary studies depicted thatGBPs present a pattern of gain and loss of genes in each family with several genes pseudogenized and some genes more divergent, indicative for the birth-and-death evolution process. Mo...
Source: Medical Microbiology and Immunology - April 13, 2022 Category: Microbiology Source Type: research

Interferon antagonists encoded by SARS-CoV-2 at a glance
AbstractThe innate immune system is a powerful barrier against invading pathogens. Interferons (IFNs) are a major part of the cytokine-mediated anti-viral innate immune response. After recognition of a pathogen by immune sensors, signaling cascades are activated that culminate in the release of IFNs. These activate cells in an autocrine or paracrine fashion eventually setting cells in an anti-viral state via upregulation of hundreds of interferon-stimulated genes (ISGs). To evade the anti-viral effect of the IFN system, successful viruses like the pandemic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) evolve...
Source: Medical Microbiology and Immunology - April 2, 2022 Category: Microbiology Source Type: research

Cytomegalovirus immune evasion sets the functional avidity threshold for protection by CD8 T cells
AbstractConflicting hallmarks are attributed to cytomegalovirus (CMV) infections. CMVs are viewed as being master tacticians in “immune evasion” by subverting essentially all pathways of innate and adaptive immunity. On the other hand, CMV disease is undeniably restricted to the immunologically immature or immunocompromised host, whereas an intact immune system prevents virus spread, cytopathogenic tissue infection, and thus pathological organ manifestations. Therefore, the popular term “immune evasion” is apparently incongruous with the control of CMV infections in the immunocompetent human host as well as in expe...
Source: Medical Microbiology and Immunology - April 1, 2022 Category: Microbiology Source Type: research

HIV-1 restriction by SERINC5
AbstractSerine incorporator 5 (SERINC5 or SER5) is a multipass transmembrane protein with ill-defined cellular activities. SER5 was recently described as a human immunodeficiency virus 1 (HIV-1) restriction factor capable of inhibiting HIV-1 that does not express its accessory protein Nef ( Δ Nef). SER5 incorporated into the viral membrane impairs the entry of HIV-1 by disrupting the fusion between the viral and the plasma membrane after envelope receptor interaction induced the first steps of the fusion process. The mechanisms of how SER5 prevents membrane fusion are not fully unders tood and viral envelope proteins were...
Source: Medical Microbiology and Immunology - March 25, 2022 Category: Microbiology Source Type: research

Streptococcus pneumoniae exerts oxidative stress, subverts antioxidant signaling and autophagy in human corneal epithelial cells that is alleviated by tert-Butylhydroquinone
AbstractStreptococcus pneumoniae is one of the leading causes of bacterial keratitis in the developing world and globally. In the current study, we have determined oxidative stress as pathogenesis ofS. pneumoniae infection in corneal tissues and human corneal epithelial cells (HCEC) and explored host immune response of HCEC towardsS. pneumoniae. We also determined whether treatment with tert-Butylhydroquinone (tBHQ), a Nrf2 inducer, could alleviate oxidative stress and reduce bacterial cytotoxicity in these cells. Oxidative stress was determined in corneal tissues of patients and HCEC by immunohistochemistry and immunofluo...
Source: Medical Microbiology and Immunology - March 24, 2022 Category: Microbiology Source Type: research

Molecular variants of SARS-CoV-2: antigenic properties and current vaccine efficacy
AbstractAn ongoing pandemic of newly emerged SARS-CoV-2 has puzzled many scientists and health care policymakers around the globe. The appearance of the virus was accompanied by several distinct antigenic changes, specifically spike protein which is a key element for host cell entry of virus and major target of currently developing vaccines. Some of these mutations enable the virus to attach to receptors more firmly and easily. Moreover, a growing number of trials are demonstrating higher transmissibility and, in some of them, potentially more serious forms of illness related to novel variants. Some of these lineages, espe...
Source: Medical Microbiology and Immunology - March 2, 2022 Category: Microbiology Source Type: research

Impaired detection of omicron by SARS-CoV-2 rapid antigen tests
We examined a total of 115 SARS-CoV-2 PCR-negative and 166 SARS-CoV-2 PCR-positive respiratory swab samples (101 omicron, 65 delta (B.1.617.2)) collected from October 2021 until January 2022 as well as cell culture-expanded clinical isolates of both VoCs. In an assessment of the analytical sensitivity in clinical specimen, the 50% limit of detection (LoD50) ranged from 1.77  × 106 to 7.03  × 107 RNA copies subjected to the RAT for omicron compared to 1.32  × 105 to 2.05  × 106 for delta. To score positive in these point-of-care tests, up to 10-fold (LoD50) or 101-fold (LoD95) higher virus loads were req...
Source: Medical Microbiology and Immunology - February 20, 2022 Category: Microbiology Source Type: research

Rapid and sensitive identification of omicron by variant-specific PCR and nanopore sequencing: paradigm for diagnostics of emerging SARS-CoV-2 variants
This study will assist the unambiguous laboratory-based diagnosis and global surveillance for this highly contagious VoC with an unprecedented degree of humoral immune escape. Moreover, we propose that specialized diagnostic laboratories should continuously update their assays for variant-specific PCRs in thespike gene of SARS-CoV-2 to readily detect and diagnose emerging variants of interest and VoCs. The combination with established nanopore sequencing procedures allows both the rapid confirmation by whole genome sequencing as well as the sensitive identification of newly emerging variants of this pandemic β-coronavirus...
Source: Medical Microbiology and Immunology - January 21, 2022 Category: Microbiology Source Type: research