Innate and adaptive immune responses to SARS-CoV-2 in humans: relevance to acquired immunity and vaccine responses.
04 Mar 2021-Clinical and Experimental Immunology (John Wiley & Sons, Ltd)-Vol. 204, Iss: 3, pp 310-320
TL;DR: In this paper, data on important innate immune responses are summarized, including cytokines, specifically interleukin (IL)-6 and complement, and potential treatments are explored Adaptive immune responses and derivative therapeutics such as monoclonal antibodies directed at spike proteins are also examined.
Abstract: The factors responsible for the spectrum of coronavirus 19 (COVID-19) disease severity and the genesis and nature of protective immunity against COVID-19 remain elusive Multiple studies have investigated the immune responses to COVID-19 in various populations, including those without evidence of COVID-19 infection Information regarding innate and adaptive immune responses to the novel severe respiratory syndrome coronavirus 2 (SARS-CoV-2) has evolved rapidly Data are accumulating defining disease phenotypes that aid in rational and informed development of new therapeutic approaches for the treatment of patients infected with SARS-CoV-2 and the development of novel vaccines In this paper, data on important innate immune responses are summarized, including cytokines, specifically interleukin (IL)-6 and complement, and potential treatments are explored Adaptive immune responses and derivative therapeutics such as monoclonal antibodies directed at spike proteins are also examined Finally, data on real-time assessments of adaptive immune responses are explored, which include CD4+ /CD8+ T cells, natural killer (NK) T cells, memory B cells and T follicular cells with specificities for COVID-19 peptides in infected and normal individuals Data of two novel vaccines have been released, both showing > 95% efficacy in preventing SARS-CoV-2 infection Analysis of humoral and cellular responses to the vaccines will determine the robustness and durability of protection In addition, long-term assessment of SARS-CoV-2 memory B and T cell-mediated immune responses in patients recovering from an infection or those with cross-reactive immunological memory will help to define risk for future SARS-CoV infections Finally, patients recovering from SARS-CoV-2 infection may experience prolonged immune activation probably due to T cell exhaustion This will be an important new frontier for study
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TL;DR: In this article, the authors reviewed how epitopes identified throughout the SARS-CoV2 proteome reveal significant correlation between number of epitopes defined and size of the antigen provenance.
189 citations
TL;DR: The long-term course of immunity among individuals with a history of COVID-19, in particular among those who received a booster vaccination, has not been well defined so far.
Abstract: The long-term course of immunity among individuals with a history of COVID-19, in particular among those who received a booster vaccination, has not been well defined so far. SARS-CoV-2-specific antibody levels were measured by ELISA over 1 year among 136 health care workers infected during the first COVID-19 wave and in a subgroup after booster vaccination approximately 1 year later. Furthermore, spike-protein-reactive memory T cells were quantified approximately 7 months after the infection and after booster vaccination. Thirty healthy individuals without history of COVID-19 who were routinely vaccinated served as controls. Levels of SARS-CoV-2-specific IgM- and IgA-antibodies showed a rapid decay over time, whereas IgG-antibody levels decreased more slowly. Among individuals with history of COVID-19, booster vaccination induced very high IgG- and to a lesser degree IgA-antibodies. Antibody levels were significantly higher after booster vaccination than after recovery from COVID-19. After vaccination with a two-dose schedule, healthy control subjects developed similar antibody levels as compared to individuals with history of COVID-19 and booster vaccination. SARS-CoV-2-specific memory T cell counts did not correlate with antibody levels. None of the study participants suffered from a reinfection. Booster vaccination induces high antibody levels in individuals with a history of COVID-19 that exceeds by far levels observed after recovery. SARS-CoV-2-specific antibody levels of similar magnitude were achieved in healthy, COVID-19-naive individuals after routine two-dose vaccination.
18 citations
TL;DR: This study summarizes the most informative methods for assessing the immune response to SARS-CoV-2 infection and describes general mechanisms of immunity, its T cell components, and presents a detailed scheme of the T cell response in SARS, including from the standpoint of determining the most promising targets for assessing its level.
Abstract: Understanding the T cell response to SARS-CoV-2 is critical to vaccine development, epidemiological surveillance, and control strategies for this disease. This review provides data from studies of the immune response in coronavirus infections. It describes general mechanisms of immunity, its T cell components, and presents a detailed scheme of the T cell response in SARS-CoV-2 infection, including from the standpoint of determining the most promising targets for assessing its level. In addition, we reviewed studies investigating post-vaccination immunity in the development of vaccines against COVID-19. This review also includes the peculiarities of immunity in different age and gender groups, and in the presence of a number of factors, for example, comorbidity or disease severity. This study summarizes the most informative methods for assessing the immune response to SARS-CoV-2 infection.
18 citations
TL;DR: In this paper , the authors reviewed the comparative immunogenic and therapeutic efficacy of Covaxin and Covishield and also discussed the probable vaccination challenges in upcoming days, and concluded that the efficacy may be diminished if the structure of spike (S) protein changes dramatically in the future.
Abstract: SARS-CoV-2 is an RNA virus that was identified for the first time in December 2019 in Wuhan, China. The World Health Organization (WHO) labeled the novel coronavirus (COVID-19) outbreak a worldwide pandemic on March 11, 2020, due to its widespread infectivity pattern. Because of the catastrophic COVID-19 outbreak, the development of safe and efficient vaccinations has become a key priority in every health sector throughout the globe. On the 13th of January 2021, the vaccination campaign against SARS-CoV-2 was launched in India and started the administration of two types of vaccines known as Covaxin and Covishield. Covishield is an adenovirus vector-based vaccine, and Covaxin was developed by a traditional method of vaccine formulation, which is composed of adjuvanted inactivated viral particles. Each vaccine's utility or efficiency is determined by its formulation, adjuvants, and mode of action. The efficacy of the vaccination depends on numeral properties like generation antibodies, memory cells, and cell-mediated immunity. According to the third-phase experiment, Covishield showed effectiveness of nearly 90%, whereas Covaxin has an effectiveness of about 80%. Both vaccination formulations in India have so far demonstrated satisfactory efficacy against numerous mutant variants of SARS-CoV-2. The efficacy of Covishield may be diminished if the structure of spike (S) protein changes dramatically in the future. In this situation, Covaxin might be still effective for such variants owing to its ability to produce multiple antibodies against various epitopes. This study reviews the comparative immunogenic and therapeutic efficacy of Covaxin and Covishield and also discussed the probable vaccination challenges in upcoming days.
17 citations
TL;DR: In this paper , the potential pathophysiologic interactions between hypertension and COVID-19 and newly emerging SARS-CoV-2 variants, and vaccines on patients with hypertension are discussed.
Abstract: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the pathogen responsible for coronavirus disease 2019 (COVID-19) has been a major cause of morbidity and mortality globally. Older age, and the presence of certain components of metabolic syndrome, including hypertension have been associated with increased risk for severe disease and death in COVID-19 patients. The role of antihypertensive agents in the pathogenesis of COVID-19 has been extensively studied since the onset of the pandemic. This review discusses the potential pathophysiologic interactions between hypertension and COVID-19 and provides an up-to-date information on the implications of newly emerging SARS-CoV-2 variants, and vaccines on patients with hypertension.
10 citations
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TL;DR: This article analyzed multiple compartments of circulating immune memory to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in 254 samples from 188 COVID-19 cases, including 43 samples at ≥ 6 months after infection.
Abstract: Understanding immune memory to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is critical for improving diagnostics and vaccines and for assessing the likely future course of the COVID-19 pandemic. We analyzed multiple compartments of circulating immune memory to SARS-CoV-2 in 254 samples from 188 COVID-19 cases, including 43 samples at ≥6 months after infection. Immunoglobulin G (IgG) to the spike protein was relatively stable over 6+ months. Spike-specific memory B cells were more abundant at 6 months than at 1 month after symptom onset. SARS-CoV-2-specific CD4+ T cells and CD8+ T cells declined with a half-life of 3 to 5 months. By studying antibody, memory B cell, CD4+ T cell, and CD8+ T cell memory to SARS-CoV-2 in an integrated manner, we observed that each component of SARS-CoV-2 immune memory exhibited distinct kinetics.
1,980 citations
TL;DR: At least a subset of sustained, severe COVID-19 may define a type of catastrophic microvascular injury syndrome mediated by activation of complement pathways and an associated procoagulant state, and could suggest targets for specific intervention.
1,787 citations
TL;DR: Most convalescent plasma samples obtained from individuals who recover from COVID-19 do not contain high levels of neutralizing activity, and rare but recurring RBD-specific antibodies with potent antiviral activity were found in all individuals tested, suggesting that a vaccine designed to elicit such antibodies could be broadly effective.
Abstract: During the COVID-19 pandemic, SARS-CoV-2 infected millions of people and claimed hundreds of thousands of lives Virus entry into cells depends on the receptor binding domain (RBD) of the SARS-CoV-2 spike protein (S) Although there is no vaccine, it is likely that antibodies will be essential for protection However, little is known about the human antibody response to SARS-CoV-21-5 Here we report on 149 COVID-19 convalescent individuals Plasmas collected an average of 39 days after the onset of symptoms had variable half-maximal pseudovirus neutralizing titres: less than 1:50 in 33% and below 1:1,000 in 79%, while only 1% showed titres above 1:5,000 Antibody sequencing revealed expanded clones of RBD-specific memory B cells expressing closely related antibodies in different individuals Despite low plasma titres, antibodies to three distinct epitopes on RBD neutralized at half-maximal inhibitory concentrations (IC50 values) as low as single digit nanograms per millitre Thus, most convalescent plasmas obtained from individuals who recover from COVID-19 do not contain high levels of neutralizing activity Nevertheless, rare but recurring RBD-specific antibodies with potent antiviral activity were found in all individuals tested, suggesting that a vaccine designed to elicit such antibodies could be broadly effective
1,675 citations
TL;DR: Infection with betacoronaviruses induces multi-specific and long-lasting T cell immunity against the structural N protein, and SARS-CoV-2-reactive T cells were found in individuals who had recovered from SARS or COVID-19 and in unexposed donors, although with different patterns of immunoreactivity.
Abstract: Memory T cells induced by previous pathogens can shape susceptibility to, and the clinical severity of, subsequent infections1. Little is known about the presence in humans of pre-existing memory T cells that have the potential to recognize severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Here we studied T cell responses against the structural (nucleocapsid (N) protein) and non-structural (NSP7 and NSP13 of ORF1) regions of SARS-CoV-2 in individuals convalescing from coronavirus disease 2019 (COVID-19) (n = 36). In all of these individuals, we found CD4 and CD8 T cells that recognized multiple regions of the N protein. Next, we showed that patients (n = 23) who recovered from SARS (the disease associated with SARS-CoV infection) possess long-lasting memory T cells that are reactive to the N protein of SARS-CoV 17 years after the outbreak of SARS in 2003; these T cells displayed robust cross-reactivity to the N protein of SARS-CoV-2. We also detected SARS-CoV-2-specific T cells in individuals with no history of SARS, COVID-19 or contact with individuals who had SARS and/or COVID-19 (n = 37). SARS-CoV-2-specific T cells in uninfected donors exhibited a different pattern of immunodominance, and frequently targeted NSP7 and NSP13 as well as the N protein. Epitope characterization of NSP7-specific T cells showed the recognition of protein fragments that are conserved among animal betacoronaviruses but have low homology to 'common cold' human-associated coronaviruses. Thus, infection with betacoronaviruses induces multi-specific and long-lasting T cell immunity against the structural N protein. Understanding how pre-existing N- and ORF1-specific T cells that are present in the general population affect the susceptibility to and pathogenesis of SARS-CoV-2 infection is important for the management of the current COVID-19 pandemic.
1,636 citations
TL;DR: Defining the immunopathological changes in patients with COVID-19 provides potential targets for drug discovery and is important for clinical management.
Abstract: Severe coronavirus disease 2019 (COVID-19) is characterized by pneumonia, lymphopenia, exhausted lymphocytes and a cytokine storm. Significant antibody production is observed; however, whether this is protective or pathogenic remains to be determined. Defining the immunopathological changes in patients with COVID-19 provides potential targets for drug discovery and is important for clinical management. In the short time since SARS-CoV2 emerged, much has been learned about the immunopathology of the infection. Here, Xuetao Cao discusses what these early insights imply for drug discovery and clinical management.
1,244 citations