Project description:The COVID-19 pandemic is entering a new era with the approval of many SARS-CoV-2 vaccines. In spite of the restoration of an almost normal way of life thanks to the immune protection elicited by these innovative vaccines, we are still facing high viral circulation, with a significant number of deaths. To further explore alternative vaccination platforms, we developed COVID-eVax-a genetic vaccine based on plasmid DNA encoding the RBD domain of the SARS-CoV-2 spike protein. Here, we describe the correlation between immune responses and the evolution of viral infection in ferrets infected with the live virus. We demonstrate COVID-eVax immunogenicity as means of antibody response and, above all, a significant T-cell response, thus proving the critical role of T-cell immunity, in addition to the neutralizing antibody activity, in controlling viral spread.
Project description:The worldwide outbreak of SARS-CoV-2, severe acute respiratory syndrome coronavirus 2 as a novel human coronavirus, was the worrying news at the beginning of 2020. Since its emergence complicated more than 870,000 individuals and led to more than 43,000 deaths worldwide. Considering to the potential threat of a pandemic and transmission severity of it, there is an urgent need to evaluate and realize this new virus's structure and behavior and the immunopathology of this disease to find potential therapeutic protocols and to design and develop effective vaccines. This disease is able to agitate the response of the immune system in the infected patients, so ARDS, as a common consequence of immunopathological events for infections with Middle East respiratory syndrome coronavirus (MERS-CoV), SARS-CoV, and SARS-CoV-2, could be the main reason for death. Here, we summarized the immune response and immune evasion characteristics in SARS-CoV, MERS-CoV, and SARS-CoV-2 and therapeutic and prophylactic strategies with a focus on vaccine development and its challenges.
Project description:Although two-dose mRNA vaccination provides excellent protection against SARS-CoV-2, there is little information about vaccine efficacy against variants of concern (VOC) in individuals above eighty years of age1. Here we analysed immune responses following vaccination with the BNT162b2 mRNA vaccine2 in elderly participants and younger healthcare workers. Serum neutralization and levels of binding IgG or IgA after the first vaccine dose were lower in older individuals, with a marked drop in participants over eighty years old. Sera from participants above eighty showed lower neutralization potency against the B.1.1.7 (Alpha), B.1.351 (Beta) and P.1. (Gamma) VOC than against the wild-type virus and were more likely to lack any neutralization against VOC following the first dose. However, following the second dose, neutralization against VOC was detectable regardless of age. The frequency of SARS-CoV-2 spike-specific memory B cells was higher in elderly responders (whose serum showed neutralization activity) than in non-responders after the first dose. Elderly participants showed a clear reduction in somatic hypermutation of class-switched cells. The production of interferon-γ and interleukin-2 by SARS-CoV-2 spike-specific T cells was lower in older participants, and both cytokines were secreted primarily by CD4 T cells. We conclude that the elderly are a high-risk population and that specific measures to boost vaccine responses in this population are warranted, particularly where variants of concern are circulating.
Project description:COVID-19 pandemic has started in December 2019 in China and quickly extended to become a worldwide health and economic emergency issue. It is caused by the novel coronavirus; SARS-CoV-2. COVID-19 patients' clinical presentations vary from asymptomatic infection or flu like symptoms to serious pneumonia which could be associated with multiple organ failure possibly leading to death. It is understood that the immune response to SARS-CoV-2 includes all elements of the immune system which could altogether succeed in viral elimination and complete cure. Meanwhile, this immune response may also lead to disease progression and could be responsible for the patient's death. Many trials have been done recently to create therapies and vaccines against human coronavirus infections such as MERS or SARS, however, till now, there is some controversy about the effectiveness and safety of antiviral drugs and vaccines which have been developed to treat and prevent this disease and its management depends mainly on supportive care. The spike glycoprotein or protein S of SARS-CoV-2 is the main promoter that induces development of neutralizing antibodies; hence, many attempts of vaccines and antiviral drugs development have been designed to be directed specifically against this protein. While some of these attempts have been proved to be efficient in in vitro settings, only few of them have been proceeded to randomized animal trials and human studies which makes COVID-19 prevention an ongoing challenge. This review describes the natural immune response scenario during COVID-19 and the vaccines development trials to create efficient vaccines thus helping to build more effective approaches for prophylaxis and management.
Project description:SARS-CoV-2 infection results in impaired interferon response in severe COVID-19 patients. However, how SARS-CoV-2 interferes with host immune response is incompletely understood. Here, we sequenced small RNAs from SARS-CoV-2-infected human cells and identified a microRNA (miRNA) derived from a recently evolved region of the viral genome. We show that the virus-derived miRNA produces two miRNA isoforms in infected cells by the enzyme Dicer and they are loaded into Argonaute proteins. Moreover, the predominant miRNA isoform targets the 3´UTR of interferon-stimulated genes and represses their expression in a miRNA-like fashion. Finally, the two viral miRNA isoforms were detected in nasopharyngeal swabs from COVID-19 patients. We propose that SARS-CoV-2 can potentially employ a virus-derived miRNA to hijack the host miRNA machinery which can lead to evasion of the interferon-mediated immune response.
Project description:Aims/hypothesisThe aim of the study was to characterise the humoral response against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in patients with diabetes. Demonstrating the ability to mount an appropriate antibody response in the presence of hyperglycaemia is relevant for the comprehension of mechanisms related to the observed worse clinical outcome of coronavirus disease 2019 (COVID-19) pneumonia in patients with diabetes and for the development of any future vaccination campaign to prevent SARS-CoV-2 infection.MethodsUsing a highly specific and sensitive measurement of antibodies by fluid-phase luciferase immunoprecipitation assays, we characterised the IgG, IgM and IgA response against multiple antigens of SARS-CoV-2 in a cohort of 509 patients with documented diagnosis of COVID-19, prospectively followed at our institution. We analysed clinical outcomes and antibody titres according to the presence of hyperglycaemia, i.e., either diagnosed or undiagnosed diabetes, at the time of, or during, hospitalisation.ResultsAmong patients with confirmed COVID-19, 139 (27.3%) had diabetes: 90 (17.7%) had diabetes diagnosed prior to the hospital admission (comorbid diabetes) while 49 (9.6%) had diabetes diagnosed at the time of admission (newly diagnosed). Diabetes was associated with increased levels of inflammatory biomarkers and hypercoagulopathy, as well as leucocytosis and neutrophilia. Diabetes was independently associated with risk of death (HR 2.32 [95% CI 1.44, 3.75], p = 0.001), even after adjustment for age, sex and other relevant comorbidities. Moreover, a strong association between higher glucose levels and risk of death was documented irrespective of diabetes diagnosis (HR 1.14 × 1.1 mmol/l [95% CI 1.08, 1.21], p < 0.001). The humoral response against SARS-CoV-2 in patients with diabetes was present and superimposable, as for timing and antibody titres, to that of non-diabetic patients, with marginal differences, and was not influenced by glucose levels. Of the measured antibody responses, positivity for IgG against the SARS-CoV-2 spike receptor-binding domain (RBD) was predictive of survival rate, both in the presence or absence of diabetes.Conclusions/interpretationThe observed increased severity and mortality risk of COVID-19 pneumonia in patients with hyperglycaemia was not the result of an impaired humoral response against SARS-CoV-2. RBD IgG positivity was associated with a remarkable protective effect, allowing for a cautious optimism about the efficacy of future vaccines against SARs-COV-2 in people with diabetes. Graphical abstract.
Project description:With the emergence of more variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the immune evasion of these variants from existing vaccines, the development of broad-spectrum vaccines is urgently needed. In this study, we designed a novel SARS-CoV-2 receptor-binding domain (RBD) subunit (RBD5m) by integrating five important mutations from SARS-CoV-2 variants of concern (VOCs). The neutralization activities of antibodies induced by the RBD5m candidate vaccine are more balanced and effective for neutralizing different SARS-CoV-2 VOCs in comparison with those induced by the SARS-CoV-2 prototype strain RBD. Our results suggest that the RBD5m vaccine is a good broad-spectrum vaccine candidate able to prevent disease from several different SARS-CoV-2 VOCs.
Project description:Variants of SARS-CoV-2 continue to emerge and evade immunity, resulting in breakthrough infections in vaccinated populations. Continued vaccination with vaccines based on the antigens of newly emerged variants does not necessarily result in long-lasting protection. Thus, there is an urgent need for the development of vaccines with a broad spectrum of protective effects. In this study, we selected hotspot mutations in the receptor binding domain (RBD) based on immune escape properties and integrated them into the original RBD protein to obtain a complexed RBD protein (cRBD). We designed a total of three cRBD (cRBD1-3) and thoroughly evaluated their immunological properties. Compared with the BA.1 RBD protein, the cRBDs induced higher levels and broader spectrum of neutralizing antibodies, with cRBD3 being the best performer. In vivo protective capacity of cRBDs was further validated in Balb/c mice attacked by live virus. In order to investigate the reason for the broad protective efficacy of cRBD, whole blood from mice that had completed the immunization process was subjected to BCR sequencing. BCR transcriptome analysis found differences in the use of VJ pairs in IGH among the groups.