Alzheimer's disease and COVID-19.

In elderly patients with COVID-19 cognitive functions decline;it has been suggested that SARS-CoV-2 infection may lead to the development of Alzheimer's disease (AD) and other long-term neurological consequences. We review several parallels between AD and COVID-19 in terms of pathogenetic mechanisms and risk factors. Possible mechanisms through which COVID-19 can initiate AD are discussed. These include systemic inflammation, hyperactivation of the renin-angiotensin system, innate immune activation, oxidative stress, and direct viral damage. It has been shown that increased expression of angiotensin-renin receptors (ACE2) may be a risk factor for COVID-19 in patients with AD. When entering the central nervous system, the SARS-CoV-2 virus can directly activate glial cell-mediated immune responses, which in turn can lead to the accumulation of beta-amyloid and the subsequent onset or progression of current AD. The involvement of inflammatory biomarkers, including interleukins (IL): IL6, IL1, as well as galectin-3, as a link between COVID-19 and AD is discussed. The rationale for the use of memantine (akatinol memantine) in patients with COVID-19 in order to prevent the development of cognitive deficits is discussed. Memantine has been shown to have a positive effect on neuroinflammatory processes in the onset or exacerbation of cognitive deficits, in reducing cerebral vasospasm and endothelial dysfunction in viral infections. Memantine therapy may improve everyday activity and reduce the risk of severe SARS-CoV-2 infection.Copyright © 2022 Ima-Press Publishing House. All rights reserved.

Sensitizing breast cancers to immune checkpoint inhibitors through CD27 agonism and vaccination against tumor-associated antigen

Project objective: Despite the recent revolution in immune checkpoint inhibitors (ICIs), only modest improvement in overall survival and likely caused by not enough potent cellular immunity among BC patients. Our lab has been focus on inducing cellular immunity against HER2+ BC through vaccination against the tumor-associated antigen HER2. Approximately 20 years ago, we performed an experimental pilot study by administrating HER2 peptide and recombinant protein pulsed dendritic cells (DC vaccine) to six patients with refractory HER2+ advanced or metastatic (stage II (>= 6 +LN), III, or stage IV) BC. We followed the patients on 2019 found that all of the six patients were still alive, 18 years after vaccination. Their blood sample were analyzed with cytometry by time-offlight (CyTOF) and found there is a significantly increased presence of CD27 expressing memory T cells in response to HER2 peptide stimulation. Recent report on the SARS-CoV2 mRNA vaccine also suggested that CD27 expressing memory T cells plays a critical role in long-lasting cellular immunity against SARS-CoV2 infection. Therefore, we hypothesized that CD27 plays a critical role in cellular immunity against BC, and the stimulation of CD27 expressing T cells with mAb targeting CD27 significantly increase the cellular immunity triggered by vaccination against tumor-associated antigen. Result(s): We recapitulate the rise of CD27+ antigen specific T cells among the vaccinated patients using a transgenic mouse model expressing human CD27. When combined the adenoviral-vector based HER2 (Ad-HER2) vaccination with a single dose of human aCD27 antibody (Varlilumab), we found there is a robust increase in the HER2 specific T cells compared to vaccination alone, especially CD27+CD44+ memory CD4 T cells, even after 120 days post vaccination. Using an ICIinsensitive syngeneic HER2+ BC models, we found 50% of mice in the combination group of aCD27 antibody plus Ad-HER2 showed total tumor regression by the end of study. When combined with anti-PD1 antibody, the combination of AdHER2 and Varlilumab leads to total tumor regression in 90% of tumor bearing mice with syngeneic HER2+ BC, indicating that the vaccination against tumor associated antigen HER2 plus anti-CD27 antibody sensitized ICI-insensitive HER2+ BC toward ICI. Conclusion(s): Our data demonstrates that the administration of anti-CD27 antibody significantly increase the long term presence of CD27+ antigen specific memory T cells after vaccination against tumor associated antigen HER2. As consequence, combination of anti-CD27 with HER2 sensitized the immune unresponsive breast cancer toward anti-PD1 antibody. Our study suggests that the vaccination against tumor-associated antigen with mAb targeting CD27 leads to the robust cellular immunity, which is required for successful ICIs against breast cancer.

Trace Elements Zinc and Selenium: Their Significance in the Conditions of the Covid-19 Pandemic

Within the conditions of the ongoing COVID-19 pandemic, when many questions regarding prevention and treatment strategies remain unsolved and the search for the best antiviral agents is underway, attention should be paid to the role of trace elements zinc and selenium in increasing the body's resistance to viral infections and their direct antiviral activity against SARS-CoV-2. Experimental data show that trace elements zinc and selenium not only actthrough regulating the immune response at all levels of humoral and cellular immunity, but also can play a significant role in adjuvant therapy for viral diseases. This is especially relevant in the case of COVID-19. Studies of the direct antiviral effect of these micro-elements testify to its 3 main ways to SARS-Cov-2: I - counteraction to virus replication and its transcription through: (i) their covalent binding to the SH-group of the cysteine of the main protease M(Pro) of the virus;(ii) inhibition of its RNA polymerase activity by zinc;II - preventing the penetration of the virus into cells due to blocking SH-groups of protein disulfide isomerase (RDI) of the protein of its spikes (peplomers);III - decreasing the adsorption capacity of the virus due to the blocking of the electrostatic interaction of SARS-CoV-2 peplomers and angiotensin-converting enzyme (ACE-2) in ultra-low, uncharacteristic oxidation states (Zn+1and Se-2). The intensity of the antiviral action of these trace elements may depend on their chemical form. It was found that zinc citrate (a five-membered complex of zinc with citric acid) and monoselenium citric acid obtained with the help of nanotechnology have a greater intensity of action and higher chemical purity. Taking into account the immunostimulating and direct antiviral effect of zinc and selenium, their use in the form of pharmaceuticals and dietary supplements should be considered as adjunctive therapy for SARS-CoV-2 in patients, or as a preventive strategy for uninfected people from risk groups during the spread of COVID-19.Copyright © Publisher PH <<Akademperiodyka>> of the NAS of Ukraine, 2023.

Cellular and humoral immune responses after SARS-CoV-2 vaccination in pediatric kidney recipients

Objective: Humoral and cellular immune responses to SARS-CoV-2 vaccination are reduced in adult kidney recipients. After pediatric kidney transplantation there are only few data available - mostly limited to monitoring of SARS-CoV-2 antibodies. Method(s): Cellular and humoral immune responses have been monitored before and after SARS-CoV-2 vaccination in pediatric kidney recipients. After in vitro stimulation with SARS-CoV-2 antigen (spike glycoprotein) virus-specific CD4 and CD8 T cells (SARS-CoV-2-Tvis) have been identified by cytokine flow cytometry. SARS-CoV-2 IgG was measured by CMIA. Result(s): Immune response after SARS-CoV-2 vaccination was analyzed in a total of 30 pediatric kidney recipients (age at 1st vaccine dose 5.2 - 17.8 years, median 14.8 years;43% male;30/30 2 vaccine doses;23/30 3 vaccine doses). At time of vaccination 22 patients (73%) received a tacrolimus (Tac)-based immunosuppression combined with mycophenolate mofetil (MMF;n = 15) or everolimus (n = 6) or neither of them (n = 1);3 patients were exposed to cyclosporine A and 5 patients to a calcineurin inhibitor (CNI)- free immunosuppression. MMF was used in 18/30 patients. After 1st dose of mRNA vaccine SARS-CoV-2 antibodies were detectable in 50% of pediatric kidney recipients, after 2nd dose in 78% and after 3rd dose in 88%. After the 2nd vaccine dose absence of humoral immune response (< 33.8 BAU/ml) was only found in case of MMF use (predominately combined with Tac). Peak IgG values (> 2,080 BAU/ml) were only detected in MMF-free regimens (6/7). Cellmediated response partially differed from humoral response, e. g., in some patients SARS-CoV2-Tvis were found despite lack of virus-specific antibodies. After 1st vaccine dose SARS-CoV-2-Tvis were detectable in 50% of pediatric kidney recipients, after 2nd dose in 92%. After 2nd vaccine dose absence or very low levels of SARS-CoV-2-Tvis (< 0.3 cells/mul) were only found in Tac-based immunosuppressive regimens, whereas higher levels (> 1.3 cells/mul) were exclusively detected in patients with MMFfree medication. Conclusion(s): After pediatric kidney transplantation humoral and cellular immune responses to SARS-CoV-2 vaccination were suboptimal, but more pronounced than in adult kidney recipients. Use of Tac and MMF was associated with impaired immune response to vaccination. SARS-CoV-2-specific humoral response corresponded only partially to cell-mediated response. Additional monitoring of SARS-CoV- 2-Tvis might be recommendable to improve assessment of the individual vaccine response and thereby to personalize the decision on the necessity of further vaccine doses.

Predominantly defective CD8+ T cell immunity to SARS-CoV-2 mRNA vaccination in lung transplant recipients.

BACKGROUND: Although mRNA vaccines have overall efficacy preventing morbidity/mortality from SARS-CoV-2 infection, immunocompromised persons remain at risk. Antibodies mostly prevent early symptomatic infection, but cellular immunity, particularly the virus-specific CD8+ T cell response, is protective against disease. Defects in T cell responses to vaccination have not been well characterized in immunocompromised hosts; persons with lung transplantation are particularly vulnerable to vaccine failure with severe illness. METHODS: Comparison groups included persons with lung transplantation and no history of COVID-19 (21 and 19 persons after initial mRNA vaccination and a third booster vaccination respectively), 8 lung transplantation participants recovered from COVID-19, and 22 non-immunocompromised healthy control individuals after initial mRNA vaccination (without history of COVID-19). Anti-spike T cell responses were assayed by stimulating peripheral blood mononuclear cells (PBMCs) with pooled small overlapping peptides spanning the SARS-CoV-2 spike protein, followed by intracellular cytokine staining (ICS) and flow cytometry for release of cytokines in response to stimulation, including negative controls (no peptide stimulation) and positive controls (phorbol myristate acetate [PMA] and ionomycin stimulation). To evaluate for low frequency memory responses, PBMCs were cultured in the presence of the mRNA-1273 vaccine for 14 days before this evaluation. RESULTS: Ionophore stimulation of PBMCs revealed a less inflammatory milieu in terms of interleukin (IL)-2, IL-4, and IL-10 profiling in lung transplantation individuals, reflecting the effect of immunosuppressive treatments. Similar to what we previously reported in healthy vaccinees, spike-specific responses in lung transplantation recipients were undetectable (< 0.01%) when tested 2 weeks after vaccination or later, but were detectable after in vitro culture of PBMCs with mRNA-1273 vaccine to enrich memory T cell responses. This was also seen in COVID-19-recovered lung transplantation recipients. Comparison of their enriched memory responses to controls revealed relatively similar CD4+ T cell memory, but markedly reduced CD8+ T cell memory both after primary vaccination or a booster dose. These responses were not correlated to age or time after transplantation. The vaccine-induced CD4+ and CD8+ responses correlated well in the healthy control group, but poorly in the transplantation groups. CONCLUSIONS: These results reveal a specific defect in CD8+ T cells, which have key roles both in transplanted organ rejection but also antiviral effector responses. Overcoming this defect will require strategies to enhance vaccine immunogenicity in immunocompromised persons.

Varying Cellular Immune Response against SARS-CoV-2 after the Booster Vaccination: A Cohort Study from Fukushima Vaccination Community Survey, Japan.

Booster vaccination reduces the incidence of severe cases and mortality related to COVID-19, with cellular immunity playing an important role. However, little is known about the proportion of the population that has achieved cellular immunity after booster vaccination. Thus, we conducted a Fukushima cohort database and assessed humoral and cellular immunity in 2526 residents and healthcare workers in Fukushima Prefecture in Japan through continuous blood collection every 3 months from September 2021. We identified the proportion of people with induced cellular immunity after booster vaccination using the T-SPOT.COVID test, and analyzed their background characteristics. Among 1089 participants, 64.3% (700/1089) had reactive cellular immunity after booster vaccination. Multivariable analysis revealed the following independent predictors of reactive cellular immunity: age < 40 years (adjusted odds ratio: 1.81; 95% confidence interval: 1.19-2.75; p-value: 0.005) and adverse reactions after vaccination (1.92, 1.19-3.09, 0.007). Notably, despite IgG(S) and neutralizing antibody titers of ≥500 AU/mL, 33.9% (349/1031) and 33.5% (341/1017) of participants, respectively, did not have reactive cellular immunity. In summary, this is the first study to evaluate cellular immunity at the population level after booster vaccination using the T-SPOT.COVID test, albeit with several limitations. Future studies will need to evaluate previously infected subjects and their T-cell subsets.

Clinical characteristics and host immunity responses of SARS-CoV-2 Omicron variant BA.2 with deletion of ORF7a, ORF7b and ORF8.

BACKGROUND: The pathogenicity and virulence of the Omicron strain have weakened significantly pathogenesis of Omicron variants. Accumulating data indicated accessory proteins play crucial roles in host immune evasion and virus pathogenesis of SARS-CoV-2. Therefore, the impact of simultaneous deletion of accessory protein ORF7a, ORF7b and ORF8 on the clinical characteristics and specific immunity in Omicron breakthrough infected patients (BIPs) need to be verified. METHODS: Herein, plasma cytokines were identified using a commercial Multi-cytokine detection kit. Enzyme-linked immunosorbent assay and pseudovirus neutralization assays were utilized to determine the titers of SARS-CoV-2 specific binding antibodies and neutralizing antibodies, respectively. In addition, an enzyme-linked immunospot assay was used to quantify SARS-CoV-2 specific T cells and memory B cells. RESULTS: A local COVID-19 outbreak was caused by the Omicron BA.2 variant, which featured a deletion of 871 base pairs (∆871 BA.2), resulting in the removal of ORF7a, ORF7b, and ORF8. We found that hospitalized patients with ∆871 BA.2 had significantly shorter hospital stays than those with wild-type (WT) BA.2. Plasma cytokine levels in both ∆871 BA.2 and WT BA.2 patients were within the normal range of reference, and there was no notable difference in the titers of SARS-CoV-2 ancestor or Omicron-specific binding IgG antibodies, neutralizing antibody titers, effector T cells, and memory B cells frequencies between ∆871 BA.2 and WT BA.2 infected adult patients. However, antibody titers in ∆871 BA.2 infected adolescents were higher than in adults. CONCLUSIONS: The simultaneous deletion of ORF7a, ORF7b, and ORF8 facilitates the rapid clearance of the BA.2 variant, without impacting cytokine levels or affecting SARS-CoV-2 specific humoral and cellular immunity in Omicron-infected individuals.

SARS-CoV2 infection induce miR-155 expression and skewed Th17/Treg balance by changing SOCS1 level: A clinical study.

BACKGROUND: One of the regulators in severe acute respiratory syndrome coronavirus2 (SARS-CoV2) infection is miRNAs. In COVID-19 patients, immunological responses to SARS-CoV2 infection may be impacted by miR-155, a miRNA associated to inflammation. MATERIALS AND METHODS: Peripheral blood mononuclear cells (PBMCs) of 50 confirmed COVID-19 patients /Healthy Controls (HCs) was isolated by Ficoll. The frequency of T helper 17 and regulatory T cells was analyzed by flowcytometry. The RNA was extracted from each sample and after synthesis of c-DNA, the relative expression of miR-155, suppressor of cytokine signaling (SOCS-1), Signal transducer and activator of transcription 3(STAT3), and Fork Head Box Protein 3 (FoxP3) was evaluated by real-time PCR. The protein level of STAT3, FoxP3 and RORγT in the isolated PBMCs measured by western blotting. The serum level of IL-10, TGF-ß, IL-17 and IL21 was assessed by ELISA method. RESULTS: The population of Th17 cells showed a significant rise, whereas Treg cells reduced in COVID-19 cases. The master transcription factor of Treg (FoxP3) and Th17 (RORγT) relative expression showed the same pattern as flowcytometry. STAT3 level of expression at RNA and protein level increased in COVID-19 cases. FOXP3 and SOCS-1 proteins were down-regulated. The relative expression of miR-155, up-regulated in PBMC of COVID-19 patients and revealed a negative correlation with SOCS-1. The serum cytokine profile showed a reduction in TGF-ß, on the other hand an increase was seen in IL-17, IL-21 and IL-10 in COVID-19 cases toward control group. CONCLUSION: Based on the studies conducted in this field, it can be suggested that Th17/Treg in covid-19 patients can be affected by miR-155 and it can be considered a valuable diagnostic and prognostic factor in this disease.

Improved Performance of the QuantiFERON-SARS-CoV-2 Assay with the Extended Set.

Multiple assays have been developed for the characterization of the functional activation of SARS-CoV-2 specific T-cells. This study was conducted to assess the post-vaccination and post-infection T cell response, as detected by the QuantiFERON-SARS-CoV-2 assay using the combination of three SARS-CoV-2 specific antigens (Ag1, Ag2 and Ag3). An amount of 75 participants with different infection and vaccination backgrounds were recruited for the evaluation of humoral and cellular immune responses. An elevated IFN-γ response in at least one Ag tube was observed in 69.2% of convalescent subjects and 63.9% of vaccinated ones. Interestingly, in a healthy unvaccinated case and three convalescents with negative IgG-RBD, we detected a positive QuantiFERON test after stimulation with Ag3. The majority of the T cell responders reacted simultaneously to the three SARS-CoV-2 specific antigens, and Ag3 demonstrated the highest rate of reactivity. At univariable analysis, the only factor that was associated with an absence of a cellular response was time from blood collection, being less than 30 days (OR:3.5, CI95% [1.15-10.50], p = 0.028). Overall, the inclusion of Ag3 improved the performance of the QuantiFERON-SARS-CoV-2 and showed a particular interest among subjects who fail to achieve a measurable antibody response after infection or vaccination.

Alzheimer's disease and COVID-19

In elderly patients with COVID-19 cognitive functions decline;it has been suggested that SARS-CoV-2 infection may lead to the development of Alzheimer's disease (AD) and other long-term neurological consequences. We review several parallels between AD and COVID-19 in terms of pathogenetic mechanisms and risk factors. Possible mechanisms through which COVID-19 can initiate AD are discussed. These include systemic inflammation, hyperactivation of the renin-angiotensin system, innate immune activation, oxidative stress, and direct viral damage. It has been shown that increased expression of angiotensin-renin receptors (ACE2) may be a risk factor for COVID-19 in patients with AD. When entering the central nervous system, the SARS-CoV-2 virus can directly activate glial cell-mediated immune responses, which in turn can lead to the accumulation of beta-amyloid and the subsequent onset or progression of current AD. The involvement of inflammatory biomarkers, including interleukins (IL): IL6, IL1, as well as galectin-3, as a link between COVID-19 and AD is discussed. The rationale for the use of memantine (akatinol memantine) in patients with COVID-19 in order to prevent the development of cognitive deficits is discussed. Memantine has been shown to have a positive effect on neuroinflammatory processes in the onset or exacerbation of cognitive deficits, in reducing cerebral vasospasm and endothelial dysfunction in viral infections. Memantine therapy may improve everyday activity and reduce the risk of severe SARS-CoV-2 infection.Copyright © 2022 Ima-Press Publishing House. All rights reserved.

Features of inflammatory periodontal diseases course in combination with a new coronavirus disease. A systematic review

Risk factors for severe COVID-19 are also associated with periodontitis. They are smoking, older age, obesity, diabetes mellitus, hypertension and cardiovascular diseases. The aim of the study was to select and analyze publications that consider a possible relationship between inflammatory periodontal diseases and the severity of COVID-19. Material and methods. The search for publications by the key words was conducted using the electronic databases: Cochrane Library;MEDLINE, eLIBRARY for systematic review. We selected 94 publications, the systematic review included 10 scientific articles presenting the results of randomized trials. Results. The results of the analysis showed the connection between COVID-19 severity and inflammatory periodontal diseases presence. In the patients with severe COVID-19 on the background of periodontitis it was established a high risk for artificial lung ventilation prescription. The course of COVID-19 is possibly depending on high expression of ACE2 receptors in oral mucosal cells and aspiration of pathogenic bacteria from periodontal tissues with saliva on the background of SARS-CoV-2 viral infection. The bacterial etiology of periodontitis plays important role of an immunological trigger that causes hyperreaction of humoral and cellular immunity, NETosis activation and NLRP3 inflammation. Conclusion. The presence of periodontitis in patients with overweight and obesity, DM or hypertension may be associated with severe COVID-19 course, possible development of complications and pneumonia.Copyright © Eco-Vector, 2023. All rights reserved.

Phase 3 Study of Safety and Immunogenicity of Gbp510 Vaccine Adjuvanted with As03 in Adults

Intro: GBP510 contains the self-assembling recombinant nanoparticle displaying SARS-CoV-2 Spike protein receptor binding domain and is adjuvanted with AS03. We report interim Phase 3 study (NCT05007951) results up to 4 weeks post-dose 2 (Data-cut: March-18-2022), where immunogenicity to the D614G ancestral strain and safety of 25mug GBP510/AS03 candidate was compared to ChAdOx1-S (Vaxzevria). Method(s): This Phase 3 randomized, active-controlled, observer-blind, parallel- group study in adults was conducted in 6 countries. Cohort1: 1,895 subjects (naive to COVID-19 vaccination and infection) randomized at 2:1 ratio (GBP510/AS03:ChAdOx1-S) to assess immunogenicity and safety;Cohort 2: 2,141 subjects at 5:1 ratio, regardless of their serostatus at screening for safety assessment. Subjects were vaccinated twice at a 4-week interval with 0.5 mL of the test vaccine (GBP510/AS03) or active control (ChAdOx1-S) in deltoid muscle. The primary objective was to demonstrate the superiority of geometric mean titer (GMT) and non-inferiority in seroconversion rate (SCR: >=4-fold rise from baseline) of neutralizing antibodies over ChAdOx1-S by live-virus neutralization assay (FRNT). Finding(s): At 2 weeks post-dose 2, GMT ratio of the two groups (Test vaccine/Active control) was 2.93 [95% CI: 2.63, 3.27], satisfying the hypothesis of superiority (95% CI lower limit> 1). The SCR difference (Test vaccine - Active control) was 10.76% [95% CI: 7.68, 14.32], satisfying the hypothesis of non- inferiority (95% CI lower limit> -5%). Good cell-mediated immune responses for Th1 cytokines were also observed with the test vaccine (FluoroSpot). The AE incidence rate for the test vaccine was higher than the active control for solicited local AEs (56.69% vs 49.20%), and comparable for solicited systemic AEs (51.21% vs 53.51%) and unsolicited AEs (13.34% vs 14.66%) after any vaccination. Conclusion(s): Higher immune responses were observed with GBP510/AS03 compared to ChAdOx1-S against D614G strain after 2 weeks post-dose 2. GBP510/AS03 showed a clinically acceptable safety profile;no safety concerns were identified during the study period.Copyright © 2023

Immune Responses to Mrna Vaccines against Sars-Cov2 in Patients with Immune-Mediated Inflammatory Rheumatic Diseases

Background/Aims Patients with immune-mediated rheumatic diseases (IMRD) are commonly treated with immunosuppressors and are prone to infections. Recently introduced mRNA SARS-Cov2 vaccines have demonstrated extraordinary efficacy across all ages. Immunosuppressed patients were excluded from phase III trials with SARS-We aim to fully characterize B and T cell immune responses elicited by mRNA SARS-Cov2 vaccines in patients with rheumatic diseases under immunotherapies, and to identify which drugs reduce vaccine's immunogenicity. Methods Humoral, CD4 and CD8 immune responses were investigated in 147 SARS-Cov2-naive patients with selected rheumatic diseases under immunosuppression after a two-dose regimen of SARS-Cov2 mRNA vaccine. Responses were compared with age, gender, and diseasematched IMRD patients not receiving immunosuppressors and with healthy controls Results IMRD patients showed decreased seroconversion rates (63% vs 100%, p=0.04) and cellular immune responses (59% vs 100%, p=0.007). Patients on methotrexate achieved seroconversion in 62% of cases and cellular responses in 80% of cases. Abatacept deeply affected humoral and cellular responses. Rituximab (31% responders) and belimumab (50% responders) showed severely impaired humoral responses but cellular responses were often preserved. Antibody titers were reduced with mycophenolate and azathioprine but preserved with leflunomide. Conclusion IMRD patients exhibit impaired SARS-CoV-2 vaccine-immunogenicity, variably reduced with immunosuppressors. Among commonly used therapies, abatacept and B-cell depleting therapies show the most deleterious effects, while anticytokines preserved immunogenicity. The effects of cumulative methotrexate and glucocorticoid doses on immunogenicity should be considered. Humoral and cellular responses are weakly correlated, but CD4 and CD8 tightly correlate. Seroconversion alone might not reflect the vaccine's immunogenicity.

MAINTAINING IMMUNOLOGICAL MEMORY TO THE SARS-CoV-2 VIRUS DURING COVID-19 PANDEMIC.

The question on the duration and effectiveness of post-infection vs post-vaccination SARS-CoV-2 immunity remains in the focus of numerous studies. The aim of the work was to examine the duration of maintained post-infection and post-vaccination SARS-CoV-2 immunity as well as formation of hybrid (vaccination after infection) and breakthrough (repeated disease or disease after vaccination) immunity in the context of an ongoing COVID-19 pandemic. 107 adults with mild or moderate COVID-19 3-18 months after the disease and 30 subjects vaccinated twice with the Sputnik V vaccine were examined 1-6 times. Antibodies against SARS-CoV-2 virus were determined by ELISA on the "SARSCoV-2-IgG quantitative-ELISA-BEST" test systems. The antibody avidity was measured by additional incubation with and without denaturing solution. Mononuclear cells were isolated from blood by gradient centrifugation, incubated with and without coronavirus S-protein for 20 hours, stained with fluorescently labeled antibodies, and the percentage of CD8highCD107a+ was counted using FACSCanto II cytometer. It was shown that in the group of convalescent and vaccinated subjects, the level of virus-specific antibodies decreased more deeply in individuals with initially high humoral response, but 9 months later the decrease slowed down and reached a plateau. The antibody avidity rose up to 50% and persisted for 18 months. Cellular immunity in recovered patients did not change for 1.5 years, while in vaccinated patients it gradually decreased 6 months later, but remained at detectable level. After revaccination, a significant increase in the level of antibodies, avidity up to 67.6% and cellular immunity returned to the initial level were noted. Hybrid immunity turned out to be significantly higher than post-infection and post-vaccination immunity. The level of antibodies increased to 1218.2 BAU/ml, avidity - to 69.85%, and cellular immunity - to 9.94%. Breakthrough immunity was significantly higher than that after the first disease. The level of antibodies rose to 1601 BAU/ml, avidity - up to 81.6%, cellular immunity - up to 13.71%. Using dynamic observation of four COVID-19 convalescents, it has been shown that in the context of the ongoing pandemic and active coronavirus mutation, natural boosting occurs both asymptomatically and as a result of a mild re-infection, which prevents disappearance of SARS-CoV-2 humoral and cellular immunity.Copyright © 2023 Saint Petersburg Pasteur Institute. All rights reserved.

IMMUNOGENICITY OF SARS-CoV-2 mRNA VACCINATION IN IDIOPATHIC CD4 LYMPHOPENIA

Background: The rapid development of SARS-CoV-2 mRNA vaccines has been a remarkable success of the COVID-19 pandemic, but vaccine-induced immunity is heterogeneous in immunocompromised populations. We sought to determine the immunogenicity of SARS-CoV-2 mRNA vaccines in a cohort of people with idiopathic CD4 lymphopenia (ICL). Method(s): 25-patients with ICL followed at the National Institutes of Health on a natural history protocol were evaluated between 2020-2022. Blood and serum was collected within 4-12 weeks after their second and/or third SARS-CoV-2 mRNA vaccine dose. Twenty-three matched healthy volunteers (HVs) provided blood samples at similar timepoints post-mRNA vaccination on a separate clinical protocol. Pre-vaccine blood samples were also used when available. Anti-spike and anti-receptor binding domain antibodies were measured. T-cell stimulation assays were performed to quantify SARS-CoV-2 specific T-cell responses. Comparisons were made with Wilcoxon test. Result(s): Twenty-participants with ICL had samples collected after their second mRNA vaccine and 7-individuals after the third dose. Median age at vaccination was 51-years (IQR: 44-62) and 12 were women (48%). Median CD4 T-cell count was 150 cells/muL (IQR: 85-188) at the time of vaccination, and 11-individuals (44%) had a baseline CD4 count <=100 cells/muL. HVs had a median age of 54-years (IQR: 43-60) with 13-women (56.5%). Anti-spike IgG antibody levels were significantly greater in HVs than those with ICL after 2-doses. Lower SARS-CoV-2 IgG antibody production was primarily observed in those with baseline CD4 T-cells <=100 cells/mul (Figure-1A). The decreased production in ICL remained after a third vaccine dose (Figure-1B). There was a significant correlation between anti-spike IgG and baseline CD4 count. Spike-specific CD4 T-cell responses in volunteers compared to those with ICL demonstrated similar levels of activation induced markers (CD154+CD69+) and cytokine production (IFNgamma+, TNFalpha+, IL2+) after two or three mRNA vaccine doses. Quantitatively the smallest responses were observed in those with lower baseline CD4 T-cells (Figure 1C-D). Minimal SARS-CoV-2 CD8 T-cell responses were detected in both groups. Conclusion(s): Patients with ICL and baseline CD4 T-cells >100 mount similar humoral and cellular immune responses to SARS-CoV-2 vaccination as healthy volunteers. Those with baseline CD4 T-cells <=100 have impaired vaccine- induced immunity and should be prioritized to additional boosters and continue other risk mitigation strategies. (Figure Presented).

Development of a New Epitope Immunogenic Structure Based on the Coronavirus Membrane Glycoprotein M Using Immunoinformatics Tools

Backgrounds: Although conventional therapies have played an essential role in the treatment of many diseases, emerging diseases require new treatment methods with less complications. Therefore, it is important to develop an effective vaccine for infections caused by the coronavirus to prevent mortality and create immunity the community. Material(s) and Method(s): In this research bioinformatics tools were used to design a vaccine against the M membrane protein of SARS-CoV-2. A total of 27 epitopes confined to B cells and MHC I and II alleles were structurally constructed in M protein for immune stimulation and antibody recognition which were used in the construction of a chimeric peptide vaccine. Finding(s): The vaccine was predicted to be a stable, antigenic, and non-allergenic compound. TRL5/vaccine complex analysis and docking simulation indicated a sufficiently stable binding with appropriated receptor activation. The immune response simulation following hypothetical immunization indicated the potential of this vaccine to stimulate the production of active and memory B cells, CD8 + T and, CD4 + T cells, and effective immunological responses induced by Th2 and Th1. Conclusion(s): The analysis of in-silico processes showed that the vaccine structure induced high antigenicity and good cellular immunity in the host body and stimulates various immune receptors such as TLR5, MHC I, and MHC II. Vaccine function was also associated with an increase in IgM and IgG antibodies and a set of Th1 and Th2 cytokines. But the final confirmation of the effectiveness of the designed vaccine requires clinical processes.Copyright © 2022, TMU Press.

INTERRELATIONS BETWEEN VIRAL LOAD AND CELLULAR IMMUNITY IN PATIENTS WITH COVID-19 OF VARYING SEVERITY.

Assessment of viral load levels in various biological samples taken from the respiratory tract can be an indicator of an ongoing process of active viral replication and may be used to monitor severe respiratory viral infections. The study of the relationship between SARS-CoV-2 viral load and immunological laboratory parameters is an important step in the search for clinical markers of COVID-19. The aim of this research was to quantify viral load in patients with COVID-19 and to identify the relationship between viral load and changes in the parameters of the cellular component of the immune system. A laboratory examination was carried out on 74 patients diagnosed with COVID-19, they were divided into 3 groups based on the severity of the disease: mild, moderate, severe. Total viral load in clinical samples was determined by the number of SARS-CoV-2 RNA copies per 100 copies of the reference RNaseP gene. A comprehensive assessment of the cellular component of the immune system was performed using flow cytometry and direct monoclonal antibodies, and the IL-6, and C-reactive protein concentrations were determined. We revealed a relationship between the development of serious clinical conditions in the patients with COVID-19, and the levels of viral load. High levels of viral RNA in biological samples correlate with main indicators of the T cell component of the immune system associated with disease severity. In a subgroup of patients with an extremely high viral load, strong positive correlations were found between the relative numbers of cytotoxic lymphocytes (CD3+CD8+), activated T lymphocytes (CD3+HLA-DR+), as well as absolute and relative numbers of activated B lymphocytes and NK cells (CD3-CD25+). Laboratory monitoring of the cellular component of the immune system, along with the assessment of viral loads, should improve early assessment of clinical condition in the patients with COVID-19. Changes in expression levels of activation markers on immune cells can be potentially viewed as indicators of recovery during COVID-19.Copyright © Nikitin Yu.V. et al., 2023 The article can be used under the Creative Commons Attribution 4.0 License.

Alzheimer's disease and COVID-19.

In elderly patients with COVID-19 cognitive functions decline;it has been suggested that SARS-CoV-2 infection may lead to the development of Alzheimer's disease (AD) and other long-term neurological consequences. We review several parallels between AD and COVID-19 in terms of pathogenetic mechanisms and risk factors. Possible mechanisms through which COVID-19 can initiate AD are discussed. These include systemic inflammation, hyperactivation of the renin-angiotensin system, innate immune activation, oxidative stress, and direct viral damage. It has been shown that increased expression of angiotensin-renin receptors (ACE2) may be a risk factor for COVID-19 in patients with AD. When entering the central nervous system, the SARS-CoV-2 virus can directly activate glial cell-mediated immune responses, which in turn can lead to the accumulation of beta-amyloid and the subsequent onset or progression of current AD. The involvement of inflammatory biomarkers, including interleukins (IL): IL6, IL1, as well as galectin-3, as a link between COVID-19 and AD is discussed. The rationale for the use of memantine (akatinol memantine) in patients with COVID-19 in order to prevent the development of cognitive deficits is discussed. Memantine has been shown to have a positive effect on neuroinflammatory processes in the onset or exacerbation of cognitive deficits, in reducing cerebral vasospasm and endothelial dysfunction in viral infections. Memantine therapy may improve everyday activity and reduce the risk of severe SARS-CoV-2 infection.Copyright © 2022 Ima-Press Publishing House. All rights reserved.

Features of inflammatory periodontal diseases course in combination with a new coronavirus disease. A systematic review.

Risk factors for severe COVID-19 are also associated with periodontitis. They are smoking, older age, obesity, diabetes mellitus, hypertension and cardiovascular diseases. The aim of the study was to select and analyze publications that consider a possible relationship between inflammatory periodontal diseases and the severity of COVID-19. Material and methods. The search for publications by the key words was conducted using the electronic databases: Cochrane Library;MEDLINE, eLIBRARY for systematic review. We selected 94 publications, the systematic review included 10 scientific articles presenting the results of randomized trials. Results. The results of the analysis showed the connection between COVID-19 severity and inflammatory periodontal diseases presence. In the patients with severe COVID-19 on the background of periodontitis it was established a high risk for artificial lung ventilation prescription. The course of COVID-19 is possibly depending on high expression of ACE2 receptors in oral mucosal cells and aspiration of pathogenic bacteria from periodontal tissues with saliva on the background of SARS-CoV-2 viral infection. The bacterial etiology of periodontitis plays important role of an immunological trigger that causes hyperreaction of humoral and cellular immunity, NETosis activation and NLRP3 inflammation. Conclusion. The presence of periodontitis in patients with overweight and obesity, DM or hypertension may be associated with severe COVID-19 course, possible development of complications and pneumonia.Copyright © Eco-Vector, 2023. All rights reserved.

PRIOR SARS-CoV-2 INFECTION PROTECTS AGAINST SYMPTOMATIC COMMON COLD CORONAVIRUSES

Background: Current COVID-19 vaccines provide substantial protection against severe COVID-19, but they do not completely eliminate subsequent SARS-CoV-2 infections. We examined incidence of and immune differences against related but different common cold coronaviruses (ccCoV) as a proxy for response against a future emerging CoV among those with SARS-CoV-2 infection, COVID-19 vaccination, or neither exposure. Method(s): We assessed incidence of ccCoV (229E, HKU1, NL63, OC43) and rhinovirus/enterovirus infections among those with documented prior SARSCoV- 2 infection (n=493), prior COVID-19 vaccine, but no SARS-CoV-2 infection (n=1,568), or no prior SARS-CoV-2 infection or vaccination (n=2,874). We conducted a retrospective review of all individuals at Boston Medical Center that underwent a comprehensive respiratory panel polymerase chain reaction (CRP-PCR) test from November 30, 2020 to October 8, 2021 to estimate infection incidence. A subset within each group was assessed for coronavirus specific humoral and cellular immune responses, via pseudovirus neutralization and peptide stimulation T cell assays. Comparisons among the three groups were done using Chi-square and multi-variate Cox-proportional hazards models. Result(s): Incidence of symptomatic ccCoV was lower in those individuals with documented prior SARS-CoV-2 infection (1.0%) compared to those with COVID-19 vaccination (2.9%) or no prior SARS-CoV-2 exposure (1.8%, p = 0.01). Rhinovirus/enterovirus incidence was similar in all three groups (range 6.2 - 8.7%). Individuals with prior SARS-CoV-2 infection and those with previous COVID-19 vaccination had similar plasma neutralization against SARS-CoV-2, OC43, and 229E spike bearing pseudoviruses. SARS-CoV-2 (p = 0.01) and OC43 nucleocapsid (p = 0.02), but not spike specific peptides, yielded higher T cell responses in individuals with a prior SARS-CoV-2 infection as compared to those with COVID-19 vaccination or no prior SARS-CoV-2 exposure. Conclusion(s): Prior SARS-CoV-2 infection, but not COVID-19 vaccination, protects against subsequent related but different ccCoV symptomatic infection. This protection against symptomatic ccCoVs may be mediated by cellular responses to non-spike proteins. Future pan-coronavirus vaccines could be improved by including both spike and non-spike antigens.