Vol 11, No 2 (2021)
- Year: 2021
- Published: 24.03.2021
- Articles: 17
- URL: https://iimmun.ru/iimm/issue/view/49
REVIEWS
Expression studies of tuberculosis susceptibility genes
Abstract
The activating research interest in the problem of tuberculosis development is due to the increase in cases of drug resistance, coinfection with HIV and hepatitis, and the lack of an effective vaccine. However, the pathogenesis of tuberculosis remains insufficiently studied at present. A significant role is assigned to hereditary factors, as the majority of those infected with Mycobacterium tuberculosis remain resistant to tuberculosis, and only in 5—15% of cases does infection lead to the development of the disease. Despite a long history of research of genetic factors of susceptibility to tuberculosis infection — from the search for monogenic forms of immune dysfunction, associations of individual tuberculosis susceptibility genes, to the analysis of genome-wide associative studies and the assessment of the characteristics of the transcriptional profiles of patients, — the problem of obtaining clinically significant results for the identification and monitoring of risk groups remains particularly acute. The search of differentially expressed genes in groups with different status of the disease (non-infected, latent tuberculosis infection, presymptomatic state, active tuberculosis, recovery from tuberculosis, non-tuberculosis infection) led to identification of a large number of data which is not overlapped in different compared groups, different ethnic groups, in the studies of the whole blood and cellular models. Merging this wealth of data followed by its reanalysis helps to verify and update results. However, there still is a large number of questions concerning our understanding of the functioning of the human organism under the influence of M. tuberculosis. In recent years, new approaches have been used to develop test systems for the diagnosis of various forms of the disease. The review considers up to date results of expression studies of susceptibility to tuberculosis, namely, objects and approaches of research changing over time, forms of the host response to the mycobacteria infection studied, the influence of different factors on the results.
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Immune response to respiratory syncytial virus infection (Orthopneumovirus)
Abstract
Respiratory syncytial virus (RSV) infects children as well as elderly and immunocompromised subjects. In 2016, RSV was renamed to Orthopneumovirus owing to virus taxonomy latinization and was also included into the Pneumoviridae family. However, in this review we will use the old and more common RSV name. RSV infection may occur throughout human lifetime as it does not induce sterilizing immunity. During RSV infection, diverse immune cells such as dendritic cells, macrophages, T cells, B cells and eosinophils are involved in the antiviral response. Some of them play an important role in eliminating RSV, while the others can provoke tissue damage. An interaction between these cells occurs through the induced cytokines and chemokines, some of which emerge at early disease stages, whereas the others — at later stages. In addition, the mentioned cells can affect the course of both primary and secondary RSV infection. A prolonged or persistent RSV infection is observed in children with T-cell immunodeficiency, emphasizing the importance of T cells in resolution of acute infection as well as for virus-specific immunological memory development. Almost all the adults and children bear RSV-specific antibodies, but that doesn't protect against the repeated infection. It was shown that high mucosal rather than serum IgG level correlated better with reduced RSV load. A growing body of RSV vaccine candidates has emerged: live-attenuated, protein-based, whole-inactivated, particle-based, subunit antigens, and nucleic acid-based vaccines. While developing vaccines, there should be taken into consideration features of anti-RSV immune response as well as age of subjects to be vaccinated. In particular, to avoid vaccine-associated aggravation of RSV infection it is justified to use live attenuated vaccines in children, whereas middle-aged and the elderly subjects might be applied with subunit vaccines. Currently, no licensed vaccine for RSV infection is available. In this review, we will detail an interaction of the RSV with diverse immune cells as well as our contemporary understanding regarding preventive vaccines in RSV infection.
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Immunological and genetic features of pathogenetic association between psoriasis and colonic dysbiosis
Abstract
Psoriasis is a multifactorial systemic immune-associated disease. It is assumed that colonic dysbiosis may contribute to its development. In this review we provide the data on colonic dysbiosis in induction and progression of psoriatic inflammation assessing a role for bacterial species: Akkermansia muciniphila, Faecalibacterium prausnitzii and Escherichia coli. On one hand, these bacterial species indicate at state of dysbiotic bacterial communities, whereas on the other hand, they are functionally associated with triggering a chain of events inducing impaired intestinal barrier transforming into chronic inflammation in the colonic mucosa and systemic inflammation. Such a scenario leads to the altered systemic reactivity of innate and adaptive immune cells, impaired function of regulatory immune cells resulting in expansion of the autoreactive skin T-cells and induction of psoriatic inflammation due to molecular mimicry between persistent Streptococcus pyogenes and cutaneous antigens. The psoriatic process is envisioned as a comorbidity with inflammatory bowel diseases. Since dysbiotic changes in psoriasis and inflammatory bowel diseases (e.g. Crohn's disease) display similar features, these diseases might potentially proceed via a similar pathogenetic chain resulting from dysbiotic changes in intestinal microbiota towards impaired intestinal barrier, chronic systemic inflammation and altered anti-inflammatory immune arm. Therefore, the data on pathogenetic pathways of the diseases comorbid with psoriasis are able to uncover yet-unknown pathogenetic components for the latter. Psoriasis as a genetically-determined disease is currently believed to be associated with single nucleotide polymorphisms (SNP) in more than four hundred genes. A role for diverse SNPs in candidate genes involved in psoriasis pathogenetic chain in antigen processing and presentation, migration of immune cells, pro-inflammatory cytokine ligation and production is discussed. Crohn's disease is associated with single nucleotide polymorphisms of the genes encoding intestinal barrier proteins potentially underlying its functional deficiency. In connection with comorbidity and similarity between microbiota-associated pathogenetic psoriasis chain and inflammatory bowel diseases, it is possible to assume that such SNPs accounting for genetic defects in the intestinal barrier are manifested as dysbiotic changes in colonic bacterial community and contribute to progression not only of inflammatory bowel diseases, but psoriasis as well.
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Tularemia in the world
Abstract
Here we review the data on the global spread of tularemia — a natural focal, especially dangerous human and animal infection caused by the bacterium Francisella tularensis. Strains of the most virulent F. tularensis subspecies tularensis circulate solely in the North America, whereas less virulent F. tularensis subspecies holarctica is found in Europe, Asia (Japan), North America, Australia (especially Tasmania). Isolates of this subspecies are isolated in territories of various climatic zones — from subarctic to subtropical, featured with diverse biocenoses in natural foci — from water to desert, with their unique hosts and carriers. Compared with the remaining subspecies of the tularemia causative agent, subspecies holarctica has a wide spread due to its ability to live in aquatic environment that markedly expands its distribution areas and shows higher ecological plasticity and stability. Infection of people by such causative agents occurs due to infected blood-sucking arthropods biting (mosquitoes, horseflies, ticks), intake of rodent-contaminated food and water, inhalation of air-dust aerosol bearing tularemia pathogen transmitted from sick rodents, as well as after direct contact with infected animals (hunting, pet care, carcass cutting). Different routes of the pathogen transmission in various countries are discussed. The peak prevalence of tularemia is observed in the North America (USA) and Europe (Sweden and Finland), as well as in Asia (Turkey). Since the mid-20th century, incidence rate of tularemia has been profoundly decreased in the Russian Federation and Kazakhstan due to preventing populations in tularemia-enzootic territories as well as those at risk of contact. In the last years, 31 European countries as well as Turkey and Japan have begun to conduct mandatory registration of tularemia cases due to an opportunity of using the pathogen for bioterrorism. The geographical distribution of the main tularemia microbe phylogenetic populations and subpopulations is demonstrated. The peak diversity of F. tularensis subsp. holarctica strains in a single country was registered in China. The major ecology- and epidemiology-related features of the tularemia causative agent are noted.
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A search for new molecular targets for optimizing plague preventive vaccination and therapy
Abstract
The causative agent of plague, Yersinia pestis, is a highly virulent bacterial pathogen and a potential bioweapon. Depending on the route of infection, two prevalent forms of the disease — bubonic and pneumonic, are known. The latter is featured by a high fatality rate. Mortality in untreated bubonic plague patients reaches up to 40—60%, whereas untreated pneumonic plague is always lethal. The development of the infectious process in susceptible host is accounted for by a whole set of pathogenicity factors in plague pathogen displaying various functional modalities being expressed depending on stage of infectious process, providing their coordinated expression. Knocking out any of such factors, in turn, may not either affect microbe virulence or lead to its attenuation. A search for new Yersinia pestis pathogenicity factors and subsequent development of highly effective subunit and live attenuated plague vaccines inducing development of pronounced cellular and humoral immune reactions, and/or assessment of their potential use as molecular targets for plague therapy still remain a pressing issue, as both currently licensed plague vaccines do not meet the WHO requirements, whereas strains of plague microbe isolated in Madagascar are resistant to all drugs recommended for plague antibacterial therapy. Here we summarize an impact of described and newly discovered pathogenicity factors into the virulence of Y. pestis strains and their protective anti-plague activity. An effect of loss of genes encoding regulatory proteins as well as mutations in the genes for various transport systems of Y. pestis on attenuation of virulent strains is described as well. Perspectives for introducing characterized antigens into prototype subunit vaccine as well as some other obtained mutants into prototypes of living attenuating vaccines were assessed. The use of antibiotics for plague treatment has been embraced by the World Health Organization Expert Committee on Plague as the “gold standard” treatment. However, concerns regarding development of antibioticresistant Y. pestis strains accounted for further exploring alternatives to plague therapy. Several research groups continue to seek for other alternative approaches, e. g. treatment with inhibitors of pathogenicity factors. Preliminary data attempting to treat plague patients with pathogenicity factor inhibitors are summarized. Antivirulence drugs targeting key microbial factors represent new promising therapeutic options in the fight against antibiotic-resistant bacteria.
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ORIGINAL ARTICLES
A single blind, placebo-controlled randomized study of the safety, reactogenicity and immunogenicity of the “EpiVacCorona” Vaccine for the prevention of COVID-19, in volunteers aged 18–60 years (phase I–II)
Abstract
Vaccination of the population is one of the most effective countermeasures in responding to the pandemic caused by novel coronavirus infection. Therefore, scientists all over the world have been working to develop effective and safe vaccines. We have developed a synthetic peptide vaccine, EpiVacCorona, against novel SARS-CoV-2 coronavirus, which is a suspension for intramuscular administration containing a composition of chemically synthesized peptide immunogens of the S protein of SARS-CoV-2 coronavirus conjugated to a carrier protein and adsorbed on aluminum hydroxide. Phase I–II clinical trials of the vaccine have started that consist of two stages: Stage 1 is an open study of the safety, reactogenicity, and immunological activity of the vaccine with the involvement of 14 volunteers aged 18–30 years; Stage 2 is a single blind, comparative, randomized placebo-controlled study with the involvement of 86 volunteers. The study involved volunteers aged 18–60 years; the vaccine was injected intramuscularly twice, spaced 21 days apart between injections. All local reactions in response to vaccine administration were mild, such as a short-term pain at the injection site. There were no signs of development of local or systemic adverse reactions. The two-dose vaccination scheme induced the production of antibodies, specific to the antigens that make up the vaccine, in 100% of the volunteers. Seroconversion with a neutralizing antibody titer ≥ 1:20 was reported in 100% of the volunteers 21 days following the second immunization dose. No seroconversion was reported in the groups of volunteers vaccinated with a placebo. The peptide-based EpiVacCorona Vaccine has low reactogenicity and is a safe, immunogenic product. Clinical Trials Identifier: NCT04527575.
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Features of developing SARS-CoV-2 nucleocapsid protein population-based seroprevalence during the first wave of the COVID-19 epidemic in the Russian Federation
Abstract
The novel coronavirus (SARS-CoV-2) pandemic, dubbed COVID-19, has become one of the most serious challenges for human populations in the vast majority of countries worldwide. Rapid spreading and increased mortality related to it required new approaches to manage epidemic processes on a global scale. One of such approaches was based on analyzing SARS-CoV-2 seroprevalence associated with COVID-19. Our aim was to summarize the results on assessing seroprevalence to the SARS-CoV-2 nucleocapsid antigen (Nc) in residents from 26 regions of the Russian Federation, carried out during the first wave of the COVID-19 epidemic.
Materials and methods. Seroprevalence distribution was examined in 26 model regions of the Russian Federation according to the unified method developed by the Rospotrebnadzor with the participation of the Federal State Institution Saint Petersburg Pasteur Research Institute of Epidemiology and Microbiology. Such approach implied formation of a group of volunteer subjects in model geographic region who were tested by ELISA for anti-Nc serum antibody level in peripheral blood. Analyzed primary data obtained in separate regions were either accepted for publication or released.
Results. The current paper finalizes the data obtained in all 26 regions of the Russian Federation. The total SARS-CoV-2 seroprevalence was 19.5 (10.0–25.6)% with the maximum and minimum value found in the Kaliningrad Region and the Republic of Crimea, respectively (50.2% vs. 4.3%). A pattern of age-related seroprevalence distribution indicates insignificant predominance of seroprevalence among subjects of 1–17 years old: 22.1 (13.1–31.8)%. Among COVID-19 convalescents positive for SARS-CoV Nc antibodies it reached 60.0 (40.0–73.3)%. The number of contact persons comprised 6285 subjects or 8.5% of total volunteer cohort, with the level of seroprevalence reaching up to 25.3 (17.95–35.8)%. A direct correlation was revealed between levels of seroprevalence in convalescent and contact volunteers. In addition, the reproductive number for SARS-CoV was calculated comprising 5.8 (4.3–8.5) suggesting that one convalescent subject can infect at least 4 healthy individuals. A high level of asymptomatic forms of COVID-19 among seropositive subjects was confirmed empirically comprising up to 93.6 (87.1–94.9)%.
Conclusion. A single cross-sectional study performed during 2020 June–August timeframe allowed to assess pattern of sex- and agerelated COVID-19 seroprevalence for general population in 26 Russian Federation regions. The data obtained may serve as a basis for the longitudinal cohort investigation with serial subject sampling. The timing and duration of study will be determined by dynamics of ongoing COVID-19 epidemic.
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The mechanisms of antibiotic resistance in major pathogens of purulent-inflammatory complications in cancer patients
Abstract
The problem of microbial antibiotic resistance and investigation of its underlying mechanisms is of paramount importance for all fields of clinical medicine, including oncology. The aim of the study was to examine the mechanisms of antibiotic resistance for major pathogens causing purulent-inflammatory complications in cancer patients. Materials and methods. In 2012—2015 there was conducted a prospective examination of 184 cancer patients, including 67 patients at the Department of Surgery no. 1 and 117 patients at the Intensive Care Unit of the Krasnoyarsk Regional Clinical Oncology Center named after A.I. Kryzhanovsky. For this, we collected bronchoalveolar lavage fluid, wound discharge and investigated the material by using bacteriological method, as well as MALDI-TOF. Antibiotic sensitivity was studied as follows: disco-diffusion, double disc method, carbapenem inactivation method, staphylococcal sensitivity — by screening method, PCR, E-test method, and serial dilutions in Muller-Hinton broth. Genotyping and antibiotic resistance mechanisms study were performed by using PCR, M-PCR, and sequencing. The WHONET program (WHO) was used, with significance level set at p < 0.05. Results. Microbiological examination of bronchoalveolar lavage fluid and wound discharge samples allowed to uncover prevalent associations of multi-resistant (MDR) and extremely resistant pathogens (XDR). The microflora of the lower respiratory tract and in the wound secretion in cancer patients were found to be dominated by non-fermenting Gram-negative bacteria reaching up to 44.5% and 48%, respectively; as well as order Enterobacteriales found in 24% and 34.9%, respectively; Gram-positive bacteria — 24% and 17.1%, respectively. Imipenem- and/or meropenem-resistant P. aeruginosa and A. baumannii, K. pneumoniae strains, were assessed for MBL production phenotypically, as well as the genes of the most common VIM, IMP types, whereas A. baumannii — for OXA-23, OXA-40, and OXA-58; and K. pneumoniae — for OXA-48. 20 strains and 16 strains of P. aeruginosa and A. baumannii, respectively, were studied by PCR. It was found that A. baumannii strains formed no MBL, but 56.3% of A. baumannii isolates (9 strains) produced OXA-23 and OXA-40 carbapenemases. Among P. aeruginosa strains there were three of them which possessed VIM (15.0%), whereas the remaining strains formed no MBL, but were resistant to carbapenems being associated with other resistance mechanisms, e.g. efflux, decreased permeability of cell wall etc. Among 6 isolates of K. pneumoniae, 1 strain produced OXA-48. In cancer patients, the percentage of methicillin-resistant strains among all members of the genus Staphylococcus was 48.9% (4 strains belonged to MRSA). PVL- MRSA strains belonged to the clones ST239/spa3(t037)/SCCmecIIIA/tst,sek,seq+ (75%) and ST8/ spa1(t008)/SCCmecIVc/sea+ (25%). MRSA ST239 showed multiple antibiotic resistance: to aminoglycosides (aacA-aphD, aadD genes were detected), linkcosamides/macrolides (the ermA gene was detected), fluoroquinolones (mutations in the GyrA gene — Ser84Leu; in GrlA- Ser80Phe), rifampicin (MIC more than 128 gg/ml; mutations in the rpoB gene are His481Asn, Ile527Met), sulfamethoxazole, tetracycline (tetM gene), and chloramphenicol (66.7% of isolates, the cat gene encoding chloramphenicol acetyl transferase was detected); but sensitive to vancomycin (MIC 1.0 gg/ ml), linezolid in 100% of cases. MRSA ST8 are resistant to aminoglycosides (aacA-aphD, aadD genes), lincosamides/macrolides (ermC gene), tetracyclines (tetK gene), chloramphenicol (cat gene); and 100% sensitive to fluoroquinolones, rifampicin (MIC 0.006 gg/ml), sulfamethaxazole, vancomycin (MIC 1.0 gg/ml), daptomycin (MIC 0.094 gg/ml), linezolid (MIC 0.75 gg/ml). Conclusion. Thus, it was found that members of the order Enterobacteriales, A. baumannii, P. aeruginosa and MRSA retain high resistance to a large number of antibacterial drugs of almost all classes. These data should be taken into account while choosing proper antibiotic therapy, as well as controlling spread of nosocomial infections caused by multiresistant microorganisms.
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Molecular epidemiology of multidrug resistant tuberculosis in Mongolia and Eastern Siberia: two independent dissemination processes for dominant strains
Abstract
Mongolia and Russia are among the countries with the high tuberculosis (TB) burden. The prevalence of tuberculosis, including multidrug-resistant tuberculosis (MDR), in Eastern Siberia bordering Mongolia is significantly higher than in the European part of Russia. In addition, unlike Mongolia, Eastern Siberia is characterized by a high prevalence of HIV infection. The cross-border spread of socially significant infections in these countries seems to occur due to their wide-range cooperation and cultural exchange. Whereas the HIV infection has no epidemiological significance for Mongolia at the moment, tuberculosis, however, has a similar prevalence on both sides of the border. The aim was to evaluate the cross-border MDR M. tuberculosis distribution in Mongolia and Eastern Siberia by using molecular genetic data. Materials and methods. A total of 1045 M. tuberculosis strains isolated in Mongolia (291) and the three regions of Eastern Siberia (754) were studied by using the MIRU-VNTR-24 loci genotyping. The CC2/W148 and CC1 subtypes were identified by the specific deletion in the kdpD gene and SNP in the pks17 gene at position 1887060, respectively. Phylogenetic analysis of MIRU-VNTR patterns was carried out by generating UPGMA tree and maximum likelihood tree. Results. The Beijing genotype was found in 75.3% (219/291) and 69.0% (520/754) from Mongolian and East Siberian collection, respectively. Common minor genotypes were LAM (11.0% and 15.1%), T (10.3% and 4.5%), and Haarlem (1.4% and 2.4%) found in Mongolia and Eastern Siberia, respectively. The genotypes S (1.3%) and Ural (5.0%) were found solely in the Russia-derived samples. The main epidemic Beijing subtypes in each country belonged to different clonal complexes (CC): the majority of Mongolian Beijing strains displayed profiles 342-32, 3819-32, 1773-32 MLVA types and belonged to the CC4 subtype; Russian Beijing strains mainly belonged to the CC1 (43.7% — 227/520) and CC2/W148 (34.8% — 181/520) subtypes. The MDR level and distribution patterns differed significantly between Mongolia and Eastern Siberia. Modeling of Beijing strain expansion evidences about extremely subtle contribution of the M. tuberculosis cross-border transmission between Mongolia and Russia. The phylogenetic reconstruction of Beijing CC4 subtype evolution in Mongolia suggests that its distribution is primarily associated with China and other countries of the Western Pacific Region. Three main phylogenetic branches of CC4 subtype were traced, which probably spread throughout Mongolia in the 11—12th centuries. It may be assumed that spreading of the epidemic Beijing CC4 subtype might occur in two stages: early period — emergence of ancestral CC4 variants in Mongolia or their introduction from China (they are homologous to the strains preserved in the Chinese population), later period — dissemination due to the active exchange of M. tuberculosis with countries of Southeast Asia, but not Russia. Conclusion. Using MIRU-VNTR-24 genotyping as well as classification according to specific single nucleotide polymorphisms specific to certain Beijing subtypes, it allowed to describe separate patterns of the epidemic variants spread in Mongolia and Russia. It has been demonstrated that emergence and spread of MDR-TB in Mongolia are entirely iatrogenic in nature, while the epidemic subtypes of the Beijing genotype (subtypes CC1 and CC2/W148) contribute markedly into the MDR-TB spreading in Eastern Siberia.
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S. pyogenes M49-16 arginine deiminase inhibits proliferative activity of human peripheral blood lymphocytes
Abstract
Arginine deiminase is one of three enzymes constituting the arginine deiminase system in bacteria. It was demonstrated that arginine deiminase exerts anti-proliferative effects on some primary and immortalized mouse and human cells. It is assumed that the inhibitory effect of arginine deiminase on cell proliferation might be related to its ability to result in the arginine exhaustion. T-lymphocytes depend on arginine for proliferation, T-cell receptor complex expression, and the differentiation of memory cells. The aim of the current study was to investigate an impact streptococcal arginine deiminase on functions of human peripheral blood lymphocytes. For this, we comparatively analyzed effects of Supernatant of Destroyed Streptococcal Cells (SDSCs) derived from parental strain S. pyogenes M49-16 and its isogenic mutant S. pyogenes M49-16delArcA bearing inactivated arginine deiminase gene (ArcA) on immune cell functions. An impact of supernatants on cell viability was estimated by staining with DAPI dye. Cell proliferation was assessed by MTT-test and flow cytometry by using the method based on intracellular protein staining with vital fluorescent CFSE (carboxyfluorescein succinimidyl ester) dye. In addition, the level of lymphocyte tyrosine phosphatase CD45 expression in various culturing conditions was evaluated. It was demonstrated that S. pyogenes M49-16 SDSCs had no impact on cells viability. Parental strain-derived SDSC exerted virtually no effect on intact cells proliferation, but considerably suppressed ConA-induced cell proliferation. At the same time, mutant strain-derived SDSC significantly stimulated spontaneous cell proliferation, but not that one after mitogen exposure. It was observed that increased proliferation was accompanied by upregulated CD45 expression, although it was not significant in all cases. These data allow to conclude that bacterial arginine deiminase could be one of pathogenicity factors able to limit lymphocyte proliferation and immune response and could be a part of pathogen strategy to suppress immune response in order to improve bacterial growth and dissemination.
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Route-coupled pathogenicity and immunogenicity of vaccinia virus variant inoculated mice
Abstract
Vaccinia virus had played a key role in the global smallpox eradication. However, in case of mass vaccination with various Vaccinia virus strains severe side effects were revealed sometimes ending up with lethal outcomes, especially in immunocompromised humans. Hence, in 1980 the World Health Organization recommended to cancel smallpox vaccination after declaring about smallpox eradication. Over the last 40 years, human population virtually lost immunity not only against smallpox, but also against other zoonotic orthopoxvirus infections, such as monkeypox, cowpox, buffalopox, and camelpox. All of them pose a represent increasing threat to human health and heighten a risk of emerging highly contagious viruses due to natural evolution of previous zoonotic orthopoxviruses. In order to prevent development of small outbreaks into spreading epidemics and, thus, to decrease a risk of emergence due to natural evolution of highly pathogenic for humans orthopoxviruses, efforts should be applied to develop safe new generation live vaccines based on Vaccinia virus with target virulence genes inactivation. These strains should be examined in laboratory animal models inoculated via different routes. Currently, Vaccinia virus often becomes attenuated to create live recombinant vaccines due to inserting target DNA sequences into the virus virulence genes resulting in their inactivation. Vaccinia virus strain LIVP used in the Russian Federation as smallpox vaccine as well as derivative attenuated variant LIVP-GFP created by using genetic engineering methods with inactivating its thymidine kinase gene were examined. Such viruses were intracerebrally inoculated into suckling mice at doses of 101 or 102 PFU/animal for neurovirulence assessment. Adult mice were infected intranasally, subcutaneously or intradermally at doses of 107 or 108 PFU/animal and clinical manifestations were analyzed for 14 days. On the 28th day after the onset, blood serum samples were collected from individual mice to measure virus specific antibody level by using ELISA. It was shown that recombinant Vaccinia virus strain LIVP-GFP displayed markedly lowered neurovirulence and pathogenicity for mice as compared to parental LIVP. Finally, intradermal route turned out to demonstrate the most safe and effective profile for immunization with both examined Vaccinia virus strains.
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Altered microbiota in the female reproductive tract as a risk factor for failure of assisted reproductive technologies
Abstract
Assisted reproductive technologies (ART) are one of the most effective ways in fighting infertility, but their effectiveness is influenced by various factors. Our study focuses on examining importance of risk factors underlying ART failure related to altered microbiome pattern in the female reproductive system. The case-control study was based on conducting a laboratory examination of 129 infertile couples applied to the Department of Assisted Reproductive Technologies due to failure of in vitro fertilization (IVF), whereas control group consisted of females with successful progressive pregnancy after ART. Chlamydia, herpes virus and cytomegalovirus were assessed by using PCR and ELISA, whereas culture method was used to detect Trichomonas vaginalis in vaginal swabs and ejaculate applying Trichomonas Modified CPLM Medium (HiMedia, India) followed by microscopy. In addition, the qualitative and quantitative composition of the vaginal biocenosis was studied with multiplex RT-PCR by using Femoflor-16 kit (DNA-technologies, Russia). Serological tests were based on measuring IgG and IgA antibodies against Chlamydia trachomatis in ELISA (diagnostic kits purchased from Vektor Best, Russia; NovaTec, Germany; ImmunoComb, Israel) as well as antibodies against immediate early HSV-1/2 proteins (BioService, Russia) and immediate early HHV-5 proteins (Vector Best, Russia). C. trachomatis and herpesvirus DNA was measured by using PCR diagnostic kits Amplisens (Interlabservice, Russia). It was found that sexually transmitted infection agents were highly prevalent in infertile couples applying to the hospital for IVF. Significant factors for non-pregnancy were vaginal dysmicrobiocenosis (OR = 7.5 (95% CI 1.04—54.1), p = 0.02) and detected T. vaginalis (OR = 2.6 (95% CI 1.12—6.4), p = 0.01). Dysbiosis of the reproductive system, including those occurring due to trichomonas infection is associated with lowered ART effectiveness. It is evident to timely detect urogenital infections and dysbiosis while preparing infertile couples for IVF cycles.
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SHORT COMMUNICATIONS
Sensitivity of Streptococcus viridans to antibacterial agents in HIV-positive patients coupled to respiratory diseases
Abstract
The streptococcus group consists of multiple species of globular Gram-positive facultative anaerobic bacteria, the classification of which is based on assessing their capacity to erythrocyte hemolysis. The viridans group streptococci produce a green coloration being a part of normal microflora in the oral cavity. However, in case of developing immunodeficiency states, oncology, and neutropenia, this pathogen can cause diseases such as bacteremia, sepsis, endocarditis, as well as pneumonia in some cases. Respiratory diseases commonly require medical assistance in HIV-infected patient cohort. The role of commensal S. viridans in development of bacterial diseases in HIV-infected patients remains poorly examined. A potential association between S. viridans and other bacterial communities, including pathogenic microorganisms is obscure. In addition, it might be worth evaluating sensitivity of S. viridans to antibacterial agents in regions with high HIV infection incidence. The aim of the study was to evaluate sensitivity to antibiotics in sputum viridans group streptococci collected from HIV-infected patients with symptomatic pneumonia. Materials and methods. The data on sputum microbiological study conducted within the 01.01.2012—01.01.2019 interval were collected from all HIV-infected patients with suspected pneumonia (n = 684) and analyzed at the Infectious Clinical Hospital No. 1 named after D.M. Dalmatov, among which S. viridans was detected in 193 patients (28.2%). Bacteriological examination of patient samples was conducted to isolate pure bacterial culture by using standard methods. Next, S. viridans was assessed for sensitivity to antibacterial agents (n = 78) according to the 2018 clinical recommendations. Initially, antibiotic resistance was assessed by disk-diffusion method as a routine approach broadly used in clinical laboratory. After that, the minimal inhibitory concentration was measured by using AutoScan 4 Microscan analyzer (bacteriological semi-automatic analyzer, Beckman Coulter, USA) to identify and determine antibacterial sensitivity. Results. A disk-diffusion method allowed to find in sputum samples streptococci resistant to penicillin in 28.2% cases, ampicillin — in 42.3% and cefazolin — in 43.6%. While assessing the minimal inhibitory concentration for antibacterial agents, similar data were obtained. Good sensitivity was found for cefotaxime, ceftriaxone, cefepime, fluoroquinolones and vancomycin.
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Immunostimulating effect of Yersinia enterocolitica-antigen conjugated gold nanoparticles
Abstract
Yersinia enterocolitica is one of the most common causative agents of nosocomial infections and the causative agent of yersiniosis, an acute infectious disease of the gastrointestinal tract. Intestinal yersiniosis caused by Y. enterocolitica is a very pressing issue for clinical and veterinary medicine requiring use of sero- and immunodiagnostics to identify the causative agent in humans, animals and animal products. Gold nanoparticles represent one of the most popular antigen nanocarriers used for immunization and vaccination. The advantages of using gold nanoparticles as vaccine delivery vehicles are associated with their relatively small size promoting their tissue penetration, low toxicity and prolonged in vivo circulation, low cost, and reproducibility. Currently, the development of new gold nanoparticle-containing diagnostic tests and vaccines against viral, bacterial, parasitic infections, including bacteria of the genus Yersinia is underway. The aim of the study was to examine efficacy of 15 nm gold nanoparticles as an immunomodulator coupled to Y. enterocolitica-derived antigen for immunization and vaccination. Final conjugate construct was used to immunize laboratory animals. The methods of immunochemical analysis assessed sensitivity and specificity of the antibodies obtained. After that, protective effects were examined in animals vaccinated with antigen conjugates and comparison preparations. It was found that immunization with a Y. enterocolitica antigen-gold nanoparticle conjugate resulted in obtaining serum that specifically recognized yersiniosis ~35 and ~14 kDa proteins evaluated in Western blot analysis. It was shown that the specific sera cross-reacted with Y. pseudotuberculosis species, but not with intestinal group Escherichia coli, Salmonella enterica, Pseudomonas aeruginosa, Proteus vulgaris, suggesting the generic specificity of the antibodies obtained. To determine the protective effect, animals were vaccinated with antigen-gold nanoparticle conjugates and comparison preparations. Two weeks after the last vaccination, mice were challenged intraperitoneally with pathogenic strain Y. enterocolitica culture. The groups immunized with antigen-gold nanoparticle conjugate had 70—80% survival rate, whereas all control mice died. It was shown that Yersinia-derived antigen-gold nanoparticle conjugates possessed higher immunomodulating activity than unconjugated antigen. The antibodies obtained can be used for effective yersiniosis immunodiagnostics. Thus, Y. enterocolitica antigen-gold nanoparticle conjugates may serve as a basis for creating preventive vaccines.
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Features of proinflammatory cytokine production in patients with allergic rhinitis combined with Helicobacter pylori-associated pathologies
Abstract
Investigating a role for pro- and anti-inflammatory cytokines in immune and inflammatory response represents one of the most pressing topics in current immunology. There have been accumulated a great body of data regarding the cytokine status during inflammatory processes in gastrointestinal tract. However, many issues remain poorly elucidated. Moreover, most of the studies were mainly aimed at examining biopsy material cytokines collected from various parts of the gastrointestinal tract or gastric juice. Here we present the data on investigating the features of cytokine production in patients with allergic rhinitis combined with H. pylori-associated diseases of the upper gastrointestinal tract. A total of 225 patients aged 18 to 40 years (mean age 29.5±6.74 years) were examined, among which 43 patients suffered from allergic rhinitis, 66 patients had inflammatory diseases of the upper gastrointestinal tract (chronic gastritis/gastroduodenitis), and 69 patients — allergic rhinitis with concomitant inflammatory diseases of the upper gastrointestinal tract. Patients were stratified to various study groups depending on diagnosed allergic rhinitis and H. pylori infection. Serum IL-6 and IL-8 level and complete blood cell count were measured. Statistical significance for difference in parameter frequencies between independent groups was assessed by using Fisher's exact test or χ2 criteria. It was shown that serum IL-6 level in H. pylori-negative patients was within the reference interval with single spikes, whereas its production was markedly increased in patients with H. pylori infection regardless of allergic pathology. Frequency of subjects with elevated serum IL-8 level was comparable between groups of patients with gastrointestinal diseases, but significantly higher than that one in the control group. An interdependence between serum IL-8 level and white blood cell count was found, which is of interest for predicting development of the inflammatory process. Thus, the serum IL-8 level during the upper gastrointestinal tract inflammatory diseases was increased regardless of verified of H. pylori infection and allergic rhinitis, whereas increased IL-6 serum level was observed solely in H. pylori-positive patients.
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Functional activity of peripheral blood monocytes in patients with opisthorchiasis coupled to liver fibrosis intensity
Abstract
The aim is to examine activity of peripheral blood monocytes from patients with opisthorchiasis coupled to intensity of liver fibrosis. Materials and Methods. A total of 74 patients with chronic opisthorchiasis (39 males and 35 females, average age 42.3 years) and 32 apparently healthy subjects (17 males and 15 females, average age 41.5 years) aged 24 to 60 years were enrolled. Opisthorchiasis was mainly diagnosed by parasitological assays to detect adult parasite eggs or bodies in duodenal contents and/or feces in all 74 patients. Liver fibrosis was assessed by elastometry according to the METAVIR scale. Functional activity of peripheral blood monocytes was performed in all patients with opisthorchiasis and healthy individuals from the control group by chemiluminescent analysis to measure intensity of reactive oxygen species production in lucigenin- and luminol-dependent spontaneous and zymosan-induced reactions. Results. Liver fibrosis F2 and F3—F4 stage according to METAVIR scale was found in 20.3% and 17.6% of patients with opisthorchiasis, respectively. While analyzing total pool of reactive oxygen species in the luminol-dependent process in patients with opisthorchiasis, a significantly decreased monocyte functional activity was observed as compared to healthy subjects that was evidenced by significantly decreased maximum intensity of produced reactive oxygen species as well as area under the chemiluminescence curve both in spontaneous and zymosan-induced reaction. Such parameters in liver fibrosis F3—F4 compared to F0—F1 in zymosan-induced response were lowered. Monocyte functional activity in spontaneous luminol-dependent reaction did not differ significantly depending on liver fibrosis intensity in patients with opisthorchiasis. The phagocytosis activation index in patients with opisthorchiasis with liver fibrosis F3—F4 compared to F0—F1 and F2 stage was lower. Similar changes were observed in the lucigenin-dependent reaction. Conclusion. The data obtained undoubtedly provide promising evidence to interpret the mechanisms behind liver fibrosis in patients with opisthorchiasis and create new opportunities for development of diagnostic and therapeutic technologies.
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OBITUARY
In memory of Vyacheslav F. Lavrov
Abstract
22 февраля 2021 года на 73 году после тяжелой болезни ушел жизни один из ведущих сотрудников нашего института — заведующий лабораторией диагностики вирусных инфекций отдела вирусологии ФГБНУ НИИВС им. И.И. Мечникова, доктор медицинских наук, профессор Вячеслав Федорович Лавров.
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