Immunological considerations for COVID-19 vaccine strategies

Adaptation of Elecsys® anti-severe acute respiratory syndrome coronavirus-2 immunoassay to dried blood spots: proof of concept

Aim: Several automated immunoassays have been validated on serum/plasma to evaluate the presence of significant levels of anti-severe acute respiratory syndrome coronavirus 2 (anti-SARS-CoV-2) antibodies, signs of a present or past infection, but the use of dried blood spots (DBS) would facilitate sampling, shipping and storage. Objective: The aim of this project was to give proof of concept of the possibility to use of the automatized Elecsys^® anti-SARS-CoV-2 immunoassay with a volumetric DBS device. Results: Linearity and correlation were satisfactory between volumetric DBS and plasma. A cut-off value was suggested and should be validated with more samples. Conclusion: this study strongly support the possibility to work with volumetric DBS instead of serum/plasma to test for anti-SARS-CoV-2 antibodies.

Optimal Allocation of the Limited COVID-19 Vaccine Supply in South Korea

Initial supply of the coronavirus disease (COVID-19) vaccine may be limited, necessitating its effective use. Herein, an age-structured model of COVID-19 spread in South Korea is parameterized to understand the epidemiological characteristics of COVID-19. The model determines optimal vaccine allocation for minimizing infections, deaths, and years of life lost while accounting for population factors, such as country-specific age distribution and contact structure, and various levels of vaccine efficacy. A transmission-blocking vaccine should be prioritized in adults aged 20–49 years and those older than 50 years to minimize the cumulative incidence and mortality, respectively. A strategy to minimize years of life lost involves the vaccination of adults aged 40–69 years, reflecting the relatively high case-fatality rates and years of life lost in this age group. An incidence-minimizing vaccination strategy is highly sensitive to vaccine efficacy, and vaccines with lower efficacy should be administered to teenagers and adults aged 50–59 years. Consideration of age-specific contact rates and vaccine efficacy is critical to optimize vaccine allocation. New recommendations for COVID-19 vaccines under consideration by the Korean Centers for Disease Control and Prevention are mainly based on a mortality-minimizing allocation strategy.

SARS-CoV-2 Immuno-Pathogenesis and Potential for Diverse Vaccines and Therapies: Opportunities and Challenges

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) is a novel coronavirus that emerged from Wuhan, China in late 2019 causing coronavirus disease-19 (COVID-19). SARS-CoV-2 infection begins by attaching to angiotensin-converting enzyme 2 receptor (ACE2) via the spike glycoprotein, followed by cleavage by TMPRSS2, revealing the viral fusion domain. Other presumptive receptors for SARS-CoV-2 attachment include CD147, neuropilin-1 (NRP1), and Myeloid C-lectin like receptor (CLR), each of which might play a role in the systemic viral spread. The pathology of SARS-CoV-2 infection ranges from asymptomatic to severe acute respiratory distress syndrome, often displaying a cytokine storm syndrome, which can be life-threatening. Despite progress made, the detailed mechanisms underlying SARS-CoV-2 interaction with the host immune system remain unclear and are an area of very active research. The process's key players include viral non-structural proteins and open reading frame products, which have been implicated in immune antagonism. The dysregulation of the innate immune system results in reduced adaptive immune responses characterized by rapidly diminishing antibody titers. Several treatment options for COVID-19 are emerging, with immunotherapies, peptide therapies, and nucleic acid vaccines showing promise. This review discusses the advances in the immunopathology of SARS-CoV-2, vaccines and therapies under investigation to counter the effects of this virus, as well as viral variants.

Review of COVID-19 Vaccines and Their Evidence in Older Adults

Coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in a global pandemic and significant loss of life. Older people are vulnerable to SARS-CoV-2 infections and complications; thus, they are a priority group to receive COVID-19 vaccines. This review discusses considerations for COVID-19 vaccines for older adults. The general concepts of vaccine effectiveness in older adults are described, particularly immune senescence and vaccine development approaches to improve immunogenicity. The types of COVID-19 vaccine platforms are also described before reviewing the available, although limited, evidence from phase 3 COVID-19 vaccine trials relevant to older adults. The BNT162b2 vaccine by Pfizer-BioNTech and mRNA-1273 vaccine from Moderna demonstrated high efficacy and immunogenicity, which were also observed in older people. While the ChAdOx1 nCoV-19 vaccine (AZD1222) by AstraZeneca demonstrated some efficacy in older people, the vaccine dose requires clarification through further studies. Finally, the Ad26.COV2.S vaccine by Janssen Pharmaceuticals shows promise as a single-dose vaccine with a potential durability of response.

COVID-19 vaccine candidates: A review

In December 2019 the first cases of atypical pneumonia caused by a novel coronavirus SARS-CoV-2 were reported in Wuhan, China. This new infection was called coronavirus disease 2019 (COVID-19). SARS-CoV-2 is primarily transmitted human-to-human via direct contact and via the air-respiratory droplets and/or aerosols. The clinical manifestations of COVID-19 could range from asymptomatic or mild non-specific symptoms to severe pneumonia with multiple organ failure and death. The virus spread rapidly to almost all the countries in the world within a few months, and on the 11th of March 2020, the World Health Organization (WHO) announced the COVID-19 pandemic. Since then, a dynamic increase in the number of COVID-19 infections and deaths has been recorded worldwide. The COVID-19 pandemic is accelerating and causing annex tensive impact on the functioning of health care and is also leading to an economic crisis in the world. Today, it is difficult to ultimately assess the long-term effects of the pandemic, although it is known that they will be experienced for decades. Therefore, the most important goal is to stop the pandemic and develop an effective vaccine against SARS-CoV-2. Using the ClinicalTrials.gov and World Health Organization databases, we shed light on the current worldwide clinical and pre-clinical trials in search for a COVID-19 vaccine.

Potential immuno-nanomedicine strategies to fight COVID-19 like pulmonary infections

COVID-19, coronavirus disease 2019, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become a pandemic. At the time of writing this (October 14, 2020), more than 38.4 million people have become affected, and 1.0 million people have died across the world. The death rate is undoubtedly correlated with the cytokine storm and other pathological pulmonary characteristics, as a result of which the lungs cannot provide sufficient oxygen to the body's vital organs. While diversified drugs have been tested as a first line therapy, the complexity of fatal cases has not been reduced so far, and the world is looking for a treatment to combat the virus. However, to date, and despite such promise, we have received very limited information about the potential of nanomedicine to fight against COVID-19 or as an adjunct therapy in the treatment regimen. Over the past two decades, various therapeutic strategies, including direct-acting antiviral drugs, immunomodulators, a few non-specific drugs (simple to complex), have been explored to treat Acute Respiratory Distress Syndrome (ARDS), Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS), influenza, and sometimes the common flu, thus, correlating and developing specific drugs centric to COVID-19 is possible. This review article focuses on the pulmonary pathology caused by SARS-CoV-2 and other viral pathogens, highlighting possible nanomedicine therapeutic strategies that should be further tested immediately.

Viral targets for vaccines against COVID-19

Vaccines are urgently needed to control the coronavirus disease 2019 (COVID-19) pandemic and to help the return to pre-pandemic normalcy. A great many vaccine candidates are being developed, several of which have completed late-stage clinical trials and are reporting positive results. In this Progress article, we discuss which viral elements are used in COVID-19 vaccine candidates, why they might act as good targets for the immune system and the implications for protective immunity.

T cell and antibody responses induced by a single dose of ChAdOx1 nCoV-19 (AZD1222) vaccine in a phase 1/2 clinical trial

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of Coronavirus Disease 2019 (COVID-19), has caused a global pandemic, and safe, effective vaccines are urgently needed1. Strong, Th1-skewed T cell responses can drive protective humoral and cell-mediated immune responses2 and might reduce the potential for disease enhancement3. Cytotoxic T cells clear virus-infected host cells and contribute to control of infection4. Studies of patients infected with SARS-CoV-2 have suggested a protective role for both humoral and cell-mediated immune responses in recovery from COVID-19 (refs. 5,6). ChAdOx1 nCoV-19 (AZD1222) is a candidate SARS-CoV-2 vaccine comprising a replication-deficient simian adenovirus expressing full-length SARS-CoV-2 spike protein. We recently reported preliminary safety and immunogenicity data from a phase 1/2 trial of the ChAdOx1 nCoV-19 vaccine (NCT04400838)7 given as either a one- or two-dose regimen. The vaccine was tolerated, with induction of neutralizing antibodies and antigen-specific T cells against the SARS-CoV-2 spike protein. Here we describe, in detail, exploratory analyses of the immune responses in adults, aged 18-55 years, up to 8 weeks after vaccination with a single dose of ChAdOx1 nCoV-19 in this trial, demonstrating an induction of a Th1-biased response characterized by interferon-γ and tumor necrosis factor-α cytokine secretion by CD4+ T cells and antibody production predominantly of IgG1 and IgG3 subclasses. CD8+ T cells, of monofunctional, polyfunctional and cytotoxic phenotypes, were also induced. Taken together, these results suggest a favorable immune profile induced by ChAdOx1 nCoV-19 vaccine, supporting the progression of this vaccine candidate to ongoing phase 2/3 trials to assess vaccine efficacy.

Principles and Challenges in anti-COVID-19 Vaccine Development

The number of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected patients keeps rising in most of the European countries despite the pandemic precaution measures. The current antiviral and anti-inflammatory therapeutic approaches are only supportive, have limited efficacy, and the prevention in reducing the transmission of SARS-CoV-2 virus is the best hope for public health. It is presumed that an effective vaccination against SARS-CoV-2 infection could mobilize the innate and adaptive immune responses and provide a protection against severe forms of coronavirus disease 2019 (COVID-19) disease. As the race for the effective and safe vaccine has begun, different strategies were introduced. To date, viral vector-based vaccines, genetic vaccines, attenuated vaccines, and protein-based vaccines are the major vaccine types tested in the clinical trials. Over 80 clinical trials have been initiated; however, only 18 vaccines have reached the clinical phase II/III or III, and 4 vaccine candidates are under consideration or have been approved for the use so far. In addition, the protective effect of the off-target vaccines, such as Bacillus Calmette-Guérin and measles vaccine, is being explored in randomized prospective clinical trials with SARS-CoV-2-infected patients. In this review, we discuss the most promising anti-COVID-19 vaccine clinical trials and different vaccination strategies in order to provide more clarity into the ongoing clinical trials.

SARS-CoV-2 vaccines and autoimmune diseases amidst the COVID-19 crisis

Coronavirus disease 2019 (COVID-19) pandemic has become challenging even for the most durable healthcare systems. It seems that vaccination, one of the most effective public-health interventions, presents a ray of hope to end the pandemic by achieving herd immunity. In this review, we aimed to cover aspects of the current knowledge of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines and vaccine candidates in the light of autoimmune inflammatory diseases (AIIDs) and to analyze their potential in terms of safety and effectiveness in patients with AIIDs. Therefore, a focused narrative review was carried out to predict the possible implications of different types of SARS-CoV-2 vaccines which confer distinct immune mechanisms to establish immune response and protection against COVID-19: whole virus (inactivated or weakened), viral vector (replicating and non-replicating), nucleic acid (RNA, DNA), and protein-based (protein subunit, virus-like particle). Still, there is uncertainty among patients with AIIDs and clinicians about the effectiveness and safety of the new vaccines. There are a variety of approaches towards building a protective immunity against SARS-CoV-2. Only high-quality clinical trials would clarify the underlying immunological mechanisms of the newly implemented vaccines/adjuvants in patients living with AIIDs.

T cell immunity to SARS-CoV-2 following natural infection and vaccination

SARS-CoV-2 first emerged in the human population in late 2019 in Wuhan, China, and in a matter of months, spread across the globe resulting in the Coronavirus Disease 19 (COVID-19) pandemic and substantial economic fallout. SARS-CoV-2 is transmitted between humans via respiratory particles, with infection presenting a spectrum of clinical manifestations ranging from asymptomatic to respiratory failure with multiorgan dysfunction and death in severe cases. Prior experiences with human pathogenic coronaviruses and respiratory virus diseases in general have revealed an important role for cellular immunity in limiting disease severity. Here, we review some of the key mechanisms underlying cell-mediated immunity to respiratory viruses and summarize our current understanding of the functional capacity and role of SARS-CoV-2-specific T cells following natural infection and vaccination.

COVID-19 and Pediatric Asthma: Clinical and Management Challenges

Asthma is the most frequent chronic condition in childhood and a current concern exists about asthma in the pediatric population and its risk for severe SARS-CoV-2 infection. Although all ages can be affected, SARS-CoV-2 infection has lower clinical impact on children and adolescents than on adults. Fever, cough and shortness of breath are the most common symptoms and signs in children; wheezing has not been frequently reported. Published studies suggest that children with asthma do not appear to be disproportionately more affected by COVID-19. This hypothesis raises two issues: is asthma (and/or atopy) an independent protective factor for COVID-19? If yes, why? Explanations for this could include the lower IFN-α production, protective role of eosinophils in the airway, and antiviral and immunomodulatory proprieties of inhaled steroids. Additionally, recent evidence supports that allergic sensitization is inversely related to ACE2 expression. Obesity is a known risk factor for COVID-19 in adults. However, in the childhood asthma–obesity phenotype, the classic atopic Th2 pattern seems to predominate, which could hypothetically be a protective factor for severe SARS-CoV-2 infection in children with both conditions. Finally, the return to school activities raises concerns, as asymptomatic children could act as vectors for the spread of the disease. Although this is still a controversial topic, the identification and management of asymptomatic children is an important approach during the SARS-CoV-2 epidemic. Focus on asthma control, risk stratification, and medication adherence will be essential to allow children with asthma to return safely to school.

Review on Up-to-Date Status of Candidate Vaccines for COVID-19 Disease

The global pandemic of COVID-19 caused by SARS-CoV-2 continues to spread and poses serious threats to public health and economic stability throughout the world. Thus, to protect the global population, developing safe and effective vaccines is mandatory to control the spread of SARS-CoV-2 pandemic. Since genomic sequences of SARS-CoV-2 and SARS-CoV-1 have similarity and use the same receptor (ACE2), it is important to learn from the development of SARS-CoV-1 vaccines for the development of SARS-CoV-2 vaccines. Normally vaccine development takes 10-15 years but vaccine development against SARS-CoV2 is going on at a very fast pace resulting in almost breakthrough methods of vaccine development by several research institutions. The whole process of vaccine development including clinical trials gets shortened and may be fast tracked to 15-18 months. Global collaborations and increased research efforts among the scientific community have led to more than 214 candidate vaccines globally. The current review highlights the different approaches and technologies used around the world for the design and development of the vaccines and also focuses on the recent status of the SARS-CoV-2 vaccine candidates under development by various institutions to combat the world threat of COVID-19 pandemic.

Evaluation of four laboratory-based SARS-CoV-2 IgG antibody immunoassays

Objectives

To evaluate the diagnostic performances of four SARS-CoV-2 IgG antibody immunoassays.

Methods

Following immunoassays were studied: Abbott's SARS-CoV-2 IgG assay, Diasorin's Liaison SARS-CoV-2 S2/S2 IgG assay, Euroimmun's Anti-SARS-CoV-2 IgG ELISA, and Roche's Elecsys Anti-SARS-CoV-2 assay. Specificity was retrospectively evaluated with 38 samples from 2019. Sensitivity samples (n = 147) were taken from SARS-CoV-2 real-time PCR-positive patients who developed COVID-19 symptoms ten days earlier.

Results

Mean specificity was 96.6%. Mean sensitivity was 62.7% from ten days after onset of symptoms, 84.4% from 15 days after onset of symptoms, and 87.5% from 20 days after onset of symptoms.

Conclusions

Specificity was high, while Abbott and Roche were 100% specific. Sensitivity increased over time, with Abbott and Roche having the highest sensitivity at all time points with ≥90% from 20 days after symptoms' onset. These findings may assist in selecting SARS-CoV-2 IgG antibody immunoassays for additional diagnostics, epidemiological research, and vaccine development.

Minor Clinical Impact of COVID-19 Pandemic on Patients With Primary Immunodeficiency in Israel

In the last few months the world has witnessed a global pandemic due to severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection causing coronavirus disease 2019 (COVID-19). Obviously, this pandemic affected individuals differently, with a significant impact on populations considered to be at high-risk. One such population, was assumed to be patients with primary genetic defect involving components or pathways of the immune system. While human immunity against COVID-19 is not fully understood, it is, so far, well documented, that both adaptive and innate cells have a critical role in protection against SARS-CoV-2. Here, we aimed to summarize the clinical and laboratory data on primary immunodeficiency (PID) patients in Israel, who were tested positive for SARS-CoV-2, in order to estimate the impact of COVID-19 on such patients. Data was collected from mid-February to end-September. During this time Israel experienced two “waves” of COVID-19 diseases; the first, from mid-February to mid-May and the second from mid-June and still ongoing at the end of data collection. A total of 20 PID patients, aged 4 months to 60 years, were tested positive for SARS-CoV-2, all but one, were detected during the second wave. Fourteen of the patients were on routine monthly IVIG replacement therapy at the time of virus detection. None of the patients displayed severe illness and none required hospitalization; moreover, 7/20 patients were completely asymptomatic. Possible explanations for the minimal clinical impact of COVID-19 pandemic observed in our PID patients include high level of awareness, extra-precautions, and even self-isolation. It is also possible that only specific immune pathways (e.g. type I interferon signaling), may increase the risk for a more severe course of disease and these are not affected in many of the PID patients. In some cases, lack of an immune response actually may be a protective measure against the development of COVID-19 sequelae.

Capsid-like particles decorated with the SARS-CoV-2 receptor-binding domain elicit strong virus neutralization activity

The rapid development of a SARS-CoV-2 vaccine is a global priority. Here, we develop two capsid-like particle (CLP)-based vaccines displaying the receptor-binding domain (RBD) of the SARS-CoV-2 spike protein. RBD antigens are displayed on AP205 CLPs through a split-protein Tag/Catcher, ensuring unidirectional and high-density display of RBD. Both soluble recombinant RBD and RBD displayed on CLPs bind the ACE2 receptor with nanomolar affinity. Mice are vaccinated with soluble RBD or CLP-displayed RBD, formulated in Squalene-Water-Emulsion. The RBD-CLP vaccines induce higher levels of serum anti-spike antibodies than the soluble RBD vaccines. Remarkably, one injection with our lead RBD-CLP vaccine in mice elicits virus neutralization antibody titers comparable to those found in patients that had recovered from COVID-19. Following booster vaccinations, the virus neutralization titers exceed those measured after natural infection, at serum dilutions above 1:10,000. Thus, the RBD-CLP vaccine is a highly promising candidate for preventing COVID-19.

Impact of Sudden Global Events on Cross-Field Research Cooperation

Since the outbreak of COVID-19, in addition to the continuous increment in the number of infected patients, the number of COVID-19-related papers has also increased significantly. According to the statistics, its number even exceeds the research of some research fields over many years. Similar to COVID-19, the related research on COVID-19 also seems highly infectious. What causes this situation? By crawling the data of COVID-19-related papers from web of Sciences this year, we found that there are three mechanisms to promote the rapid growth of the number of COVID-19 papers: incentive mechanism, cross-field collaboration mechanism, and potential impact mechanism of writing papers. To understand the impact of COVID-19 on cross-domain paper network further, we proposed a new construction method of multi-field paper association structure network based on COVID-19. The paper association mechanism and the wall breaking principle between multiple research fields were found through the experiments. Then, combined with the constructed network, we gave the knowledge dissemination model of the new discoveries in multiple fields and obtained some relevant new findings.

The Joint Impact of COVID-19 Vaccination and Non-Pharmaceutical Interventions on Infections, Hospitalizations, and Mortality: An Agent-Based Simulation

Background

Vaccination against SARS-CoV-2 has the potential to significantly reduce transmission and morbidity and mortality due to COVID-19. This modeling study simulated the comparative and joint impact of COVID-19 vaccine efficacy and coverage with and without non-pharmaceutical interventions (NPIs) on total infections, hospitalizations, and deaths.

Methods

An agent-based simulation model was employed to estimate incident SARS-CoV-2 infections and COVID-19-associated hospitalizations and deaths over 18 months for the State of North Carolina, a population of roughly 10.5 million. Vaccine efficacy of 50% and 90% and vaccine coverage of 25%, 50%, and 75% (at the end of a 6-month distribution period) were evaluated. Six vaccination scenarios were simulated with NPIs (i.e., reduced mobility, school closings, face mask usage) maintained and removed during the period of vaccine distribution.

Results

In the worst-case vaccination scenario (50% efficacy and 25% coverage), 2,231,134 new SARS-CoV-2 infections occurred with NPIs removed and 799,949 infections with NPIs maintained. In contrast, in the best-case scenario (90% efficacy and 75% coverage), there were 450,575 new infections with NPIs maintained and 527,409 with NPIs removed. When NPIs were removed, lower efficacy (50%) and higher coverage (75%) reduced infection risk by a greater magnitude than higher efficacy (90%) and lower coverage (25%) compared to the worst-case scenario (absolute risk reduction 13% and 8%, respectively).

Conclusion

Simulation results suggest that premature lifting of NPIs while vaccines are distributed may result in substantial increases in infections, hospitalizations, and deaths. Furthermore, as NPIs are removed, higher vaccination coverage with less efficacious vaccines can contribute to a larger reduction in risk of SARS-CoV-2 infection compared to more efficacious vaccines at lower coverage. Our findings highlight the need for well-resourced and coordinated efforts to achieve high vaccine coverage and continued adherence to NPIs before many pre-pandemic activities can be resumed.

SARS-CoV-2 structural features may explain limited neutralizing-antibody responses

Neutralizing antibody responses of SARS-CoV-2-infected patients may be low and of short duration. We propose here that coronaviruses employ a structural strategy to avoid strong and enduring antibody responses. Other viruses induce optimal and long-lived neutralizing antibody responses, thanks to 20 or more repetitive, rigid antigenic epitopes, spaced by 5–10 nm, present on the viral surface. Such arrays of repetitive and highly organized structures are recognized by the immune system as pathogen-associated structural patterns (PASPs), which are characteristic for pathogen surfaces. In contrast, coronaviruses are large particles with long spikes (S protein) embedded in a fluid membrane. Therefore, the neutralizing epitopes (which are on the S protein) are loosely “floating” and widely spaced by an average of about 25 nm. Consequently, recruitment of complement is poor and stimulation of B cells remains suboptimal, offering an explanation for the inefficient and short-lived neutralizing antibody responses.

Immunotherapies and COVID-19 related Neurological manifestations: A Comprehensive Review Article

In December 2019, an outbreak of pandemic severe respiratory distress syndrome coronavirus disease 2019 (COVID-19) initially occurred in China, has spread the world resulted in serious threats to human public health. Uncommon neurological manifestations with pathophysiological symptoms were observed in infected patients including headache, seizures, and neuroimmunological disorders. Regardless of whether these neurological symptoms are direct or indirect casual infection relationship, this novel viral infection has a relevant impact on the neuroimmune system that requires a neurologist's careful assessment. Recently, the use of immunotherapy has been emerged in fighting against COVID-19 infection despite the uncertain efficiency in managing COVID-19 related disorders or even its proven failure by increasing its severity. Herein, the author is addressing the first approaches in using immunotherapies in controlling COVID-19 viral impact on the brain by highlighting their role in decreasing or increasing infection risks among subjects. This point of view review article supports the use of immunotherapies in managing COVID-19 neurological disorders but in optimal timing and duration to ensure the maximum therapeutic outcome by reducing morbidity and mortality rate. Based on recently published data, the current review article highlights the beneficial effects and drawbacks of using immunotherapies to combat COVID-19 and its neurological symptoms.

COVID-19 in teriflunomide-treated patients with multiple sclerosis: A case report and literature review

BACKGROUND

. Teriflunomide is an immunomodulatory drug approved for Multiple Sclerosis (MS) treatment that inhibits dihydroorotate dehydrogenase, a mitochondrial enzyme involved in the de novo pyrimidine synthesis pathway. This mechanism can produce antiviral effects, thus teriflunomide has gained attention during COVID-19 pandemic. Moreover, in the last months, some case-reports have been published describing MS patients treated with teriflunomide who developed mild and self-limiting forms of COVID-19.

METHODS

Here, we describe the case of a 57-year-old man affected by MS, and treated with teriflunomide, who developed a mild form of SARS-CoV-2 infection. Moreover, we provide a detailed literature review about the available cases of COVID-19 in MS patients treated with teriflunomide. We report clinical features, disease course and outcome, and we discuss similarities and differences among patients.

RESULTS

Apart from the present report, since February 2020, five papers have been published describing 14 MS patients who developed SARS-CoV-2 infection during teriflunomide treatment. Patients were mostly female (53%), with an average age of 50.5 (±11.3) years. Median EDSS was 2.25 (range 0-6). The average time on treatment with teriflunomide was 3.7 (± 1.6) years. Relevant comorbidities were present in 4 patients (27%). Regarding SARS-CoV-2 infection, the most common symptom was fever (100%) followed by gastrointestinal disturbances (67%), fatigue (55%) and cough (55%). 5 patients were hospitalized and 2 required oxygen support. In patient hospitalized (n=5) compared to the others (n=10), age was significantly higher (59.6 vs 45.9 years, p=0.025) while gender, EDSS, duration of teriflunomide therapy and comorbidities were not significantly different. Outcome was good for all patients with a variable recovery time, ranging from few days to some weeks. Teriflunomide was continued during the entire course of SARS-CoV-2 infection in all patients except for two. Compared to the patients already described, our patient was 7 years older, average time on teriflunomide treatment was about 2.5 years shorter, and median EDSS was 1.5 point lower. Despite significant comorbidities, the outcome was good since our patient was hospitalized but he did not require oxygen supplementation nor intensive care and was able to return at home after only 10 days. Teriflunomide therapy was continued throughout the period.

CONCLUSION

Available data suggest that teriflunomide therapy should not be discontinued in MS patients who develop SARS-CoV-2 infection, also in presence of significant comorbidities or clinical conditions requiring hospitalization. Additional studies are necessary to assess if the drug can also have a protective role against SARS-CoV-2.

Highlight of severe acute respiratory syndrome coronavirus-2 vaccine development against COVID-19 pandemic

The pandemic caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has brought an unprecedented impact upon the global economy and public health. Although the SARS-CoV-2 virology has been gradually investigated, measures to combat this new threat in public health are still absent. To date, no certificated drug or vaccine has been developed for the treatment or prevention of coronavirus disease Extensive researches and international coordination has been conducted to rapidly develop novel vaccines against SARS-CoV-2 pandemic. Several major breakthroughs have been made through the identification of the genetic sequence and structural/non-structural proteins of SARS-CoV-2, which enabled the development of RNA-, DNA-based vaccines, subunit vaccines, and attenuated viral vaccines. In this review article, we present an overview of the recent advances of SARS-CoV-2 vaccines and the challenges that may be encountered in the development process, highlighting the advantages and disadvantages of these approaches that may help in effectively countering COVID-19.

Multidimensional Evaluation of All-Cause Mortality Risk and Survival Analysis for Hospitalized Patients with COVID-19

Background: Coronavirus disease 2019 (COVID-19) has caused over 3.8 million deaths globally. Up to date, the number of death in 2021 is more than that in 2020 globally. Here, we aimed to compare clinical characteristics of deceased patients and recovered patients, and analyze the risk factors of death to help reduce mortality of COVID-19. Methods: In this retrospective study, a total of 2719 COVID-19 patients were enrolled, including 109 deceased patients and 2610 recovered patients. Medical records of all patients were collected between February 4, 2020, and April 7, 2020. Clinical characteristics, laboratory indices, treatments, and deep-learning system- assessed lung lesion volumes were analyzed. The effect of different medications on survival time of fatal cases was also investigated. Results: The deceased patients were older (73 years versus 60 years) and had a male predominance. Nausea (10.1% versus 4.1%) and dyspnea (54.1% versus 39.2%) were more common in deceased patients. The proportion of patients with comorbidities in deceased patients was significantly higher than those in recovered patients. The median times from hospital admission to outcome in deceased patients and recovered patients were 9 days and 13 days, respectively. Patients with severe or critical COVID-19 were more frequent in deceased group. Leukocytosis (11.35×10⁹/L versus 5.60×10⁹/L) and lymphocytopenia (0.52×10⁹/L versus 1.58×10⁹/L) were shown in patients who died. The level of prothrombin time, activated partial prothrombin time, D-dimer, aspartate aminotransferase, alanine aminotransferase, urea, creatinine, creatine kinase, glucose, brain natriuretic peptide, and inflammatory indicators were significantly higher in deceased patients than in recovered patients. The volumes of ground-glass, consolidation, total lesions and total lung in all patients were quantified. Complications were more common in deceased patients than in recovered patients; respiratory failure (57.8%), septic shock (36.7%), and acute respiratory distress syndrome (26.6%) were the most common complications in patients who died. Many treatments were more frequent in deceased patients, such as antibiotic therapy (88.1% versus 53.7%), glucocorticoid treatment (70.6% versus 11.0%), intravenous immunoglobin treatment (36.6% versus 4.9%), invasive mechanical ventilation (62.3% versus 3.8%). Antivirals, antibiotics, traditional Chinese medicines and glucocorticoid treatment may significantly increase the survival time of fatal cases. Quantitative computed tomography imaging results were correlated with biochemical markers. Conclusions: Most patients with fatal outcomes were more likely to have common comorbidities. The leading causes of death were respiratory failure and multiple organ dysfunction syndrome. Acute respiratory distress syndrome, respiratory failure and septic shock were the most common serious complications. Antivirals, antibiotics, traditional Chinese medicines, and glucocorticoid treatment may prolong the survival time of deceased patients with COVID-19.

Hematopoietic stem cell transplantation for autoimmune diseases in the time of COVID-19: EBMT guidelines and recommendations

Coronavirus disease-19 (COVID-19), caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), represents one of the biggest challenges of 21st century, threatening public health around the globe. Increasing age and presence of co-morbidities are reported risk factors for severe disease and mortality, along with autoimmune diseases (ADs) and immunosuppressive treatments such as haematopoietic stem cell transplantation (HSCT), which are also associated with adverse outcomes. We review the impact of the pandemic on specific groups of patients with neurological, rheumatological, and gastroenterological indications, along with the challenges delivering HSCT in adult and pediatric populations. Moving forward, we developed consensus-based guidelines and recommendations for best practice and quality of patient care in order to support clinicians, scientists, and their multidisciplinary teams, as well as patients and their carers. These guidelines aim to support national and international organizations related to autoimmune diseases and local clinical teams delivering HSCT. Areas of unmet need and future research questions are also highlighted. The waves of the COVID-19 pandemic are predicted to be followed by an "endemic" phase and therefore an ongoing risk within a "new normality". These recommendations reflect currently available evidence, coupled with expert opinion, and will be revised according to necessary modifications in practice.

EMERGENCIA DE SARS-COV-2. ASPECTOS BÁSICOS SOBRE SU ORIGEN, EPIDEMIOLOGÍA, ESTRUCTURA Y PATOGENIA PARA CLÍNICOS

SARS-CoV-2 es el tercer coronavirus que emerge en las últimas dos décadas y produce la enfermedad denominada COVID-19 (enfermedad infecciosa por coronavirus 2019). Ha demostrado ser fácilmente transmisible entre humanos con una rápida diseminación mundial y declarada como pandemia el 11 de marzo 2020. A la fecha ha causado millones de casos y muertes, disrupción de servicios sanitarios y severas consecuencias sociales, económicas y políticas en todos los países. Los estudios filogenéticos lo relacionan con SARS-CoV presentes en murciélagos. Comparte características de patogenicidad con sus parientes más cercanos, SARS-CoV y MERS-CoV. 15 a 20% de los afectados presentan cuadros graves. A la fecha no se cuenta con antivirales efectivos ni vacunas. Para un adecuado control se hace imprescindible dilucidar aspectos epidemiológicos, moleculares y de patogenicidad. En esta revisión se presenta información básica sobre epidemiología, origen, estructura y patogenia de SARS-CoV-2.

Potential Risks and Benefits of Multiple Sclerosis Immune Therapies in the COVID-19 Era: Clinical and Immunological Perspectives

Coronavirus SARS-CoV2 has emerged as one of the greatest infectious disease health challenges in a century. Patients with multiple sclerosis (MS) have a particular vulnerability to infections through their use of immunosuppressive disease-modifying therapies (DMTs). Specific DMTs pose particular risk based on their mechanisms of action (MOA). As a result, patients require individualized approaches to starting new treatments and continuation of therapy. Additionally, vaccinations must be considered carefully, and individuals on long-term B cell-depleting therapies may have diminished immune responses to vaccination, based on preserved T cells and diminished but present antibody titers to influenza vaccines. We review the immunology behind these treatments and their impact on COVID-19, as well as the current recommendations for best practices for use of DMTs in patients with MS.

Multifunctional biomolecule nanostructures for cancer therapy

Biomolecule-based nanostructures are inherently multifunctional and harbour diverse biological activities, which can be explored for cancer nanomedicine. The supramolecular properties of biomolecules can be precisely programmed for the design of smart drug delivery vehicles, enabling efficient transport in vivo, targeted drug delivery and combinatorial therapy within a single design. In this Review, we discuss biomolecule-based nanostructures, including polysaccharides, nucleic acids, peptides and proteins, and highlight their enormous design space for multifunctional nanomedicines. We identify key challenges in cancer nanomedicine that can be addressed by biomolecule-based nanostructures and survey the distinct biological activities, programmability and in vivo behaviour of biomolecule-based nanostructures. Finally, we discuss challenges in the rational design, characterization and fabrication of biomolecule-based nanostructures, and identify obstacles that need to be overcome to enable clinical translation.

Artificial intelligence predicts the immunogenic landscape of SARS-CoV-2 leading to universal blueprints for vaccine designs

The global population is at present suffering from a pandemic of Coronavirus disease 2019 (COVID-19), caused by the novel coronavirus Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). The goal of this study was to use artificial intelligence (AI) to predict blueprints for designing universal vaccines against SARS-CoV-2, that contain a sufficiently broad repertoire of T-cell epitopes capable of providing coverage and protection across the global population. To help achieve these aims, we profiled the entire SARS-CoV-2 proteome across the most frequent 100 HLA-A, HLA-B and HLA-DR alleles in the human population, using host-infected cell surface antigen presentation and immunogenicity predictors from the NEC Immune Profiler suite of tools, and generated comprehensive epitope maps. We then used these epitope maps as input for a Monte Carlo simulation designed to identify statistically significant “epitope hotspot” regions in the virus that are most likely to be immunogenic across a broad spectrum of HLA types. We then removed epitope hotspots that shared significant homology with proteins in the human proteome to reduce the chance of inducing off-target autoimmune responses. We also analyzed the antigen presentation and immunogenic landscape of all the nonsynonymous mutations across 3,400 different sequences of the virus, to identify a trend whereby SARS-COV-2 mutations are predicted to have reduced potential to be presented by host-infected cells, and consequently detected by the host immune system. A sequence conservation analysis then removed epitope hotspots that occurred in less-conserved regions of the viral proteome. Finally, we used a database of the HLA haplotypes of approximately 22,000 individuals to develop a “digital twin” type simulation to model how effective different combinations of hotspots would work in a diverse human population; the approach identified an optimal constellation of epitope hotspots that could provide maximum coverage in the global population. By combining the antigen presentation to the infected-host cell surface and immunogenicity predictions of the NEC Immune Profiler with a robust Monte Carlo and digital twin simulation, we have profiled the entire SARS-CoV-2 proteome and identified a subset of epitope hotspots that could be harnessed in a vaccine formulation to provide a broad coverage across the global population.

Artificial intelligence predicts the immunogenic landscape of SARS-CoV-2 leading to universal blueprints for vaccine designs

The global population is at present suffering from a pandemic of Coronavirus disease 2019 (COVID-19), caused by the novel coronavirus Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). The goal of this study was to use artificial intelligence (AI) to predict blueprints for designing universal vaccines against SARS-CoV-2, that contain a sufficiently broad repertoire of T-cell epitopes capable of providing coverage and protection across the global population. To help achieve these aims, we profiled the entire SARS-CoV-2 proteome across the most frequent 100 HLA-A, HLA-B and HLA-DR alleles in the human population, using host-infected cell surface antigen presentation and immunogenicity predictors from the NEC Immune Profiler suite of tools, and generated comprehensive epitope maps. We then used these epitope maps as input for a Monte Carlo simulation designed to identify statistically significant "epitope hotspot" regions in the virus that are most likely to be immunogenic across a broad spectrum of HLA types. We then removed epitope hotspots that shared significant homology with proteins in the human proteome to reduce the chance of inducing off-target autoimmune responses. We also analyzed the antigen presentation and immunogenic landscape of all the nonsynonymous mutations across 3,400 different sequences of the virus, to identify a trend whereby SARS-COV-2 mutations are predicted to have reduced potential to be presented by host-infected cells, and consequently detected by the host immune system. A sequence conservation analysis then removed epitope hotspots that occurred in less-conserved regions of the viral proteome. Finally, we used a database of the HLA haplotypes of approximately 22,000 individuals to develop a "digital twin" type simulation to model how effective different combinations of hotspots would work in a diverse human population; the approach identified an optimal constellation of epitope hotspots that could provide maximum coverage in the global population. By combining the antigen presentation to the infected-host cell surface and immunogenicity predictions of the NEC Immune Profiler with a robust Monte Carlo and digital twin simulation, we have profiled the entire SARS-CoV-2 proteome and identified a subset of epitope hotspots that could be harnessed in a vaccine formulation to provide a broad coverage across the global population.

A guide to vaccinology: from basic principles to new developments

Immunization is a cornerstone of public health policy and is demonstrably highly cost-effective when used to protect child health. Although it could be argued that immunology has not thus far contributed much to vaccine development, in that most of the vaccines we use today were developed and tested empirically, it is clear that there are major challenges ahead to develop new vaccines for difficult-to-target pathogens, for which we urgently need a better understanding of protective immunity. Moreover, recognition of the huge potential and challenges for vaccines to control disease outbreaks and protect the older population, together with the availability of an array of new technologies, make it the perfect time for immunologists to be involved in designing the next generation of powerful immunogens. This Review provides an introductory overview of vaccines, immunization and related issues and thereby aims to inform a broad scientific audience about the underlying immunological concepts.

This Review, aimed at a broad scientific audience, provides an introductory guide to the history, development and immunological basis of vaccines, immunization and related issues to provide insight into the challenges facing immunologists who are designing the next generation of vaccines.

The Current Status of Drug Repositioning and Vaccine Developments for the COVID-19 Pandemic

Since the outbreak of coronavirus disease 2019 (COVID-19) was first identified, the world has vehemently worked to develop treatments and vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) at an unprecedented speed. Few of the repositioned drugs for COVID-19 have shown that they were efficacious and safe. In contrast, a couple of vaccines against SARS-CoV-2 will be ready for mass rollout early next year. Despite successful vaccine development for COVID-19, the world will face a whole new set of challenges including scale-up manufacturing, cold-chain logistics, long-term safety, and low vaccine acceptance. We highlighted the importance of knowledge sharing and collaboration to find innovative answers to these challenges and to prepare for newly emerging viruses.

Harnessing Cellular Immunity for Vaccination against Respiratory Viruses

Severe respiratory viral infections, such as influenza, metapneumovirus (HMPV), respiratory syncytial virus (RSV), rhinovirus (RV), and coronaviruses, including severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), cause significant mortality and morbidity worldwide. These viruses have been identified as important causative agents of acute respiratory disease in infants, the elderly, and immunocompromised individuals. Clinical signs of infection range from mild upper respiratory illness to more serious lower respiratory illness, including bronchiolitis and pneumonia. Additionally, these illnesses can have long-lasting impact on patient health well beyond resolution of the viral infection. Aside from influenza, there are currently no licensed vaccines against these viruses. However, several research groups have tested various vaccine candidates, including those that utilize attenuated virus, virus-like particles (VLPs), protein subunits, and nanoparticles, as well as recent RNA vaccines, with several of these approaches showing promise. Historically, vaccine candidates have advanced, dependent upon the ability to activate the humoral immune response, specifically leading to strong B cell responses and neutralizing antibody production. More recently, it has been recognized that the cellular immune response is also critical in proper resolution of viral infection and protection against detrimental immunopathology associated with severe disease and therefore, must also be considered when analyzing the efficacy and safety of vaccine candidates. These candidates would ideally result in robust CD4+ and CD8+ T cell responses as well as high-affinity neutralizing antibody. This review will aim to summarize established and new approaches that are being examined to harness the cellular immune response during respiratory viral vaccination.

Harnessing Cellular Immunity for Vaccination against Respiratory Viruses

Severe respiratory viral infections, such as influenza, metapneumovirus (HMPV), respiratory syncytial virus (RSV), rhinovirus (RV), and coronaviruses, including severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), cause significant mortality and morbidity worldwide. These viruses have been identified as important causative agents of acute respiratory disease in infants, the elderly, and immunocompromised individuals. Clinical signs of infection range from mild upper respiratory illness to more serious lower respiratory illness, including bronchiolitis and pneumonia. Additionally, these illnesses can have long-lasting impact on patient health well beyond resolution of the viral infection. Aside from influenza, there are currently no licensed vaccines against these viruses. However, several research groups have tested various vaccine candidates, including those that utilize attenuated virus, virus-like particles (VLPs), protein subunits, and nanoparticles, as well as recent RNA vaccines, with several of these approaches showing promise. Historically, vaccine candidates have advanced, dependent upon the ability to activate the humoral immune response, specifically leading to strong B cell responses and neutralizing antibody production. More recently, it has been recognized that the cellular immune response is also critical in proper resolution of viral infection and protection against detrimental immunopathology associated with severe disease and therefore, must also be considered when analyzing the efficacy and safety of vaccine candidates. These candidates would ideally result in robust CD4+ and CD8+ T cell responses as well as high-affinity neutralizing antibody. This review will aim to summarize established and new approaches that are being examined to harness the cellular immune response during respiratory viral vaccination.

How to Understand Herd Immunity in the Context of COVID-19

COVID-19 is an emerging rapidly evolving situation, which is widely disseminated all over the world. During this period, the concept of herd immunity is often mentioned, but it is easily misunderstood. In the context of COVID-19, this article comprehensively expounds the concept and purpose of herd immunity, the necessary conditions for realizing the herd immunity, the restrictive conditions for the application of herd immunity, and the challenges faced by the realization of herd immunity. Furthermore, starting from the "three elements," which refers to the characteristics of the pathogen and the population, as well as the behaviors taken by the population, the relationship between herd immunity and COVID-19 is deeply analyzed. Based on the aforementioned, the implementation of corresponding measures is expected to slow down the spread of the epidemic and even eliminate pathogens.

Validation of dried blood spot sample modifications to two commercially available COVID-19 IgG antibody immunoassays

Aim: Coronavirus disease 2019 antibody testing often relies on venous blood collection, which is labor-intensive, inconvenient and expensive compared with finger-stick capillary dried blood spot (DBS) collection. The purpose of our work was to determine if two commercially available anti-severe acute respiratory syndrome coronavirus 2 enzyme-linked immunosorbent assays for IgG antibodies against spike S1 subunit and nucleocapsid proteins could be validated for use with DBS. Materials & methods: Kit supplied reagents were used to extract DBS, and in-house DBS calibrators were included on every run. Results: Positive/negative concordance between DBS and serum was 100/99.3% for the spike S1 subunit assay and 100/98% for the nucleocapsid assay. Conclusion: Validation of the DBS Coronavirus disease 2019 IgG antibody assays demonstrated that serum and DBS can produce equivalent results with minimal kit modifications.

The known unknowns of T cell immunity to COVID-19

Tremendous progress has been made in understanding the role of T cell immunity in acute and convalescent COVID-19 infection. Here we shed light on the "known unknowns" of pre-existing and acquired T cell responses in relation to acute and convalescent SARS-CoV-2 infection.

Frontrunners in the race to develop a SARS-CoV-2 vaccine

Numerous studies continue to be published on the COVID-19 pandemic that is being caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Given the rapidly evolving global response to SARS-CoV-2, here we primarily review the leading COVID-19 vaccine strategies that are currently in Phase III clinical trials. Nonreplicating viral vector strategies, inactivated virus, recombinant protein subunit vaccines, and nucleic acid vaccine platforms are all being pursued in an effort to combat the infection. Preclinical and clinal trial results of these efforts are examined as well as the characteristics of each vaccine strategy from the humoral and cellular immune responses they stimulate, effects of any adjuvants used, and the potential risks associated with immunization such as antibody-dependent enhancement. A number of promising advancements have been made toward the development of multiple vaccine candidates. Preliminary data now emerging from phase III clinical trials show encouraging results for the protective efficacy and safety of at least 3 frontrunning candidates. There is hope that one or more will emerge as potent weapons to protect against SARS-CoV-2.

Invited Editorial. COVID-19 Vaccine: Hope and reality

Nil

New vaccine production platforms used in developing SARS-CoV-2 vaccine candidates

The threat of the current coronavirus disease pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is accelerating the development of potential vaccines. Candidate vaccines have been generated using existing technologies that have been applied for developing vaccines against other infectious diseases. Two new types of platforms, mRNA- and viral vector-based vaccines, have been gaining attention owing to the rapid advancement in their methodologies. In clinical trials, setting appropriate immunological endpoints plays a key role in evaluating the efficacy and safety of candidate vaccines. Updated information about immunological features from individuals who have or have not been exposed to SARS-CoV-2 continues to guide effective vaccine development strategies. This review highlights key strategies for generating candidate SARS-CoV-2 vaccines and considerations for vaccine development and clinical trials.

Drawing Comparisons between SARS-CoV-2 and the Animal Coronaviruses

The COVID-19 pandemic, caused by a novel zoonotic coronavirus (CoV), SARS-CoV-2, has infected 46,182 million people, resulting in 1,197,026 deaths (as of 1 November 2020), with devastating and far-reaching impacts on economies and societies worldwide. The complex origin, extended human-to-human transmission, pathogenesis, host immune responses, and various clinical presentations of SARS-CoV-2 have presented serious challenges in understanding and combating the pandemic situation. Human CoVs gained attention only after the SARS-CoV outbreak of 2002-2003. On the other hand, animal CoVs have been studied extensively for many decades, providing a plethora of important information on their genetic diversity, transmission, tissue tropism and pathology, host immunity, and therapeutic and prophylactic strategies, some of which have striking resemblance to those seen with SARS-CoV-2. Moreover, the evolution of human CoVs, including SARS-CoV-2, is intermingled with those of animal CoVs. In this comprehensive review, attempts have been made to compare the current knowledge on evolution, transmission, pathogenesis, immunopathology, therapeutics, and prophylaxis of SARS-CoV-2 with those of various animal CoVs. Information on animal CoVs might enhance our understanding of SARS-CoV-2, and accordingly, benefit the development of effective control and prevention strategies against COVID-19.

Immunopathology, host-virus genome interactions, and effective vaccine development in SARS-CoV-2

Coronaviruses are a group of enveloped RNA viruses that are diversely found in humans and now declared a global pandemic by the World Health Organization in March 2020. The population's susceptibility to these highly pathogenic coronaviruses has contributed to large outbreaks, evolved into public health events, and rapidly transmitted globally. Thus, there is an urgent need to develop effective therapies and vaccines against this disease. In the primary stage of severe acute respiratory syndrome coronavirus (SARS-COV-2) infection, the signs and symptoms are nonspecific, and many more cases have been observed than initially expected. Genome sequencing is performed regularly to identify genetic changes to SARS-COV-2, and vaccine development is focused on manufacture, production, and based on specific problems, and very few are available on recent developments in the prevention of outbreaks. The aim of this review article to explore recent updates on SARS-COV-2 in the context of pathogenesis during disease progression, and innate acquired mechanisms of defense, This includes advances in diagnostics, susceptibility, and severity of host-virus genome interactions, modes of transmission, active compounds being used in pre-clinical and clinical trials for the treatment of patients, vaccine developments, and the effectiveness of SARS-COV-2 prevention and control measures. We have summarized the importance of pathophysiology immune response, Diagnostics, vaccine development currently approaches explored for SARS-COV-2.

Exposome and Immunity Training: How Pathogen Exposure Order Influences Innate Immune Cell Lineage Commitment and Function

Immune memory is a defining characteristic of adaptive immunity, but recent work has shown that the activation of innate immunity can also improve responsiveness in subsequent exposures. This has been coined “trained immunity” and diverges with the perception that the innate immune system is primitive, non-specific, and reacts to novel and recurrent antigen exposures similarly. The “exposome” is the cumulative exposures (diet, exercise, environmental exposure, vaccination, genetics, etc.) an individual has experienced and provides a mechanism for the establishment of immune training or immunotolerance. It is becoming increasingly clear that trained immunity constitutes a delicate balance between the dose, duration, and order of exposures. Upon innate stimuli, trained immunity or tolerance is shaped by epigenetic and metabolic changes that alter hematopoietic stem cell lineage commitment and responses to infection. Due to the immunomodulatory role of the exposome, understanding innate immune training is critical for understanding why some individuals exhibit protective phenotypes while closely related individuals may experience immunotolerant effects (e.g., the order of exposure can result in completely divergent immune responses). Research on the exposome and trained immunity may be leveraged to identify key factors for improving vaccination development, altering inflammatory disease development, and introducing potential new prophylactic treatments, especially for diseases such as COVID-19, which is currently a major health issue for the world. Furthermore, continued exposome research may prevent many deleterious effects caused by immunotolerance that frequently result in host morbidity or mortality.

Total-Body PET Imaging in Infectious Diseases

Total-body PET enables high-sensitivity imaging with dramatically improved signal-to-noise ratio. These enhanced performance characteristics allow for decreased PET scanning times acquiring data "total-body wide" and can be leveraged to decrease the amount of radiotracer required, thereby permitting more frequent imaging or longer imaging periods during radiotracer decay. Novel approaches to PET imaging of infectious diseases are emerging, including those that directly visualize pathogens in vivo and characterize concomitant immune responses and inflammation. Efforts to develop these imaging approaches are hampered by challenges of traditional imaging platforms, which may be overcome by novel total-body PET strategies.