Assessing Immune Response to SARS-CoV-2 Infection

Applying the digital data and the bioinformatics tools in SARS-CoV-2 research

Bioinformatics has been playing a crucial role in the scientific progress to fight against the pandemic of the coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The advances in novel algorithms, mega data technology, artificial intelligence and deep learning assisted the development of novel bioinformatics tools to analyze daily increasing SARS-CoV-2 data in the past years. These tools were applied in genomic analyses, evolutionary tracking, epidemiological analyses, protein structure interpretation, studies in virus-host interaction and clinical performance. To promote the in-silico analysis in the future, we conducted a review which summarized the databases, web services and software applied in SARS-CoV-2 research. Those digital resources applied in SARS-CoV-2 research may also potentially contribute to the research in other coronavirus and non-coronavirus viruses.

Effector-Memory B-Lymphocytes and Follicular Helper T-Lymphocytes as Central Players in the Immune Response in Vaccinated and Nonvaccinated Populations against SARS-CoV-2

Vaccines have been recognized as having a central role in controlling the COVID-19 pandemic; however, most vaccine development research is focused on IgG-induced antibodies. Here, we analyzed the generation of IgGs related to SARS-CoV-2 and the changes in B- and T-lymphocyte proportions following vaccination against COVID-19. We included samples from 69 volunteers inoculated with the Pfizer-BioNTech (BNT162b2), Astra Zeneca (AZD1222 Covishield), or Sputnik V (Gam-COVID-Vac) vaccines. IgGs related to SARS-CoV-2 increased after the first vaccine dose compared with the nonvaccinated group (Pfizer, p = 0.0001; Astra Zeneca, p < 0.0001; Sputnik V, p = 0.0089). The results of the flow cytometry analysis of B- and T-lymphocytes showed a higher proportion of effector-memory B-lymphocytes in both first and second doses when compared with the nonvaccinated subjects. FcRL4+ cells were increased in second-dose-vaccinated COVID-19(−) and recovered COVID-19(+) participants when compared with the nonvaccinated participants. COVID-19(−) participants showed a lower proportion of follicular helper T-lymphocytes (TFH) in the second dose when compared with the first-vaccine-dose and nonvaccinated subjects. In conclusion, after the first vaccine dose, immunization against SARS-CoV-2 induces IgG production, and this could be mediated by TFH and effector-memory B-lymphocytes. Our data can be used in the design of vaccine schedules to evaluate immuno-bridging from a cellular point of view.

ABO blood group association and COVID-19. COVID-19 susceptibility and severity: a review

INTRODUCTION

The SARS-CoV-2 pandemic has been affecting the health and economic, as well as social, life of the entire globe since the end of 2019. The virus causes COVID-19, with a wide range of symptoms among the infected individuals, from asymptomatic infection to mortality. This, along with a high infection rate, prompted efforts to investigate the potential mechanisms of the different clinical manifestations caused by SARS-CoV-2 among the infected populations.

HYPOTHESIS

One of the possible mechanisms that has been reported is the ABO blood system polymorphism. Indeed, one of the major proposed mechanisms is the presence of naturally occurring anti-A antibodies in individuals of groups O and B, which could be partially protective against SARS-CoV-2 virions.

OBJECTIVE AND METHOD

This article aimed to review the published data on the potential effect of the ABO blood group system on the susceptibility to COVID-19 and the disease progression and outcomes.

RESULTS

The reviewed data suggest that individuals of blood group A are at a higher risk of infection with SARS-CoV-2 and may develop severe COVID-19 outcomes, whereas blood group O is considered protective against the infection, to some extent. However, some of the available studies seem to have been influenced by unaccounted confounders and biases.

CONCLUSION

Therefore, further appropriately controlled studies are warranted to fully investigate the possible association between the ABO blood groups and COVID-19 susceptibility and severity.

Antibody Response of BNT162b2 and CoronaVac Platforms in Recovered Individuals Previously Infected by COVID-19 against SARS-CoV-2 Wild Type and Delta Variant

Vaccinating recovered patients previously infected by COVID-19 with mRNA vaccines to boost their immune response against wild-type viruses (WT), we aimed to investigate whether vaccine platform and time of vaccination affect immunogenicity against the SARS-CoV-2 WT and Delta variant (DV). Convalescent patients infected by COVID-19 were recruited and received one booster dose of the BNT162b2 (PC-B) or CoronaVac (PC-C) vaccines, while SARS-CoV-2 naïve subjects received two doses of the BNT162b2 (CN-B) or CoronaVac (CN-C) vaccines. The neutralizing antibody in sera against the WT and DV was determined with live virus neutralization assay (vMN). The vMN geometric mean titre (GMT) against WT in recovered individuals previously infected by COVID-19 reduced significantly from 60.0 (95% confidence interval (CI), 46.5-77.4) to 33.9 (95% CI, 26.3-43.7) at 6 months post recovery. In the PC-B group, the BNT162b2 vaccine enhanced antibody response against WT and DV, with 22.3-fold and 20.4-fold increases, respectively. The PC-C group also showed 1.8-fold and 2.2-fold increases for WT and DV, respectively, after receiving the CoronaVac vaccine. There was a 10.6-fold increase in GMT in the CN-B group and a 1.3-fold increase in the CN-C group against DV after full vaccination. In both the PC-B and PC-C groups, there was no difference between GMT against WT and DV after vaccination. Subjects in the CN-B and CN-C groups showed inferior GMT against DV compared with GMT against WT after vaccination. In this study, one booster shot effectively enhanced the pre-existing neutralizing activity against WT and DV in recovered subjects.

Differential Antibody Response to mRNA COVID-19 Vaccines in Healthy Subjects

Knowledge about development and duration of virus-specific antibodies after COVID-19 vaccination is important for understanding how to limit the pandemic via vaccination in different populations and societies. However, the clinical utility of postvaccination testing of antibody response and selection of targeted SARS-CoV-2 antigen(s) has not been established. The results of such testing from clinical teams independent from vaccine manufacturers are also limited. Here, we report the initial results of an ongoing clinical study on evaluation of antibody response to four different SARS-CoV-2 antigens after first and second dose of Pfizer and Moderna mRNA vaccines and at later time points. We revealed a peak of antibody induction after the vaccine boosting dose with a gradual decline of antibody levels at later time. Anti-nucleocapsid antibody was not induced by spike protein-encoding vaccines and this may continue to serve as a marker of previous SARS-CoV-2 infection. No differences between the two vaccines in terms of antibody response were revealed. Age and gender dependencies were determined to be minimal within the healthy adult (but not aged) population. Our results suggest that postvaccination testing of antibody response is an important and feasible tool for following people after vaccination and selecting individuals who might require a third dose of vaccine at an earlier time point or persons who may not need a second dose due to previous SARS-CoV-2 infection. IMPORTANCE Now that authorized vaccines for COVID-19 have been widely used, it is important to understand how they induce antivirus antibodies, which antigens are targeted, how long antibodies circulate, and how personal health conditions and age may affect this humoral immunity. Here, we report induction and time course of multiple anti-SARS-CoV-2 antibody responses in healthy individuals immunized with Pfizer and Moderna mRNA vaccines. We also determined the age and gender dependence of the antibody response and compared antibody levels to responses seen in those who have recovered from COVID-19. Our results suggest the importance of screening for antibody response to multiple antigens after vaccination in order to reveal individuals who require early and late additional boosting and those who may not need second dose due to prior SARS-CoV-2 infection.

PDE4 inhibition as a therapeutic strategy for improvement of pulmonary dysfunctions in Covid-19 and cigarette smoking

Angiotensin-converting enzyme 2 (ACE2) is the binding-site and entry-point for SARS-CoV-2 in human and highly expressed in the lung. Cigarette smoking (CS) is the leading cause of pulmonary and cardiovascular diseases. Chronic CS leads to upregulation of bronchial ACE2 inducing a high vulnerability in COVID-19 smoker patients. Interestingly, CS-induced dysregulation of pulmonary renin-angiotensin system (RAS) in part contributing into the potential pathogenesis COVID-19 pneumonia and acute respiratory distress syndrome (ARDS). Since, CS-mediated ACE2 activations is not the main pathway for increasing the risk of COVID-19, it appeared that AngII/AT₁R might induce an inflammatory-burst in COVID-19 response by up-regulating cyclic nucleotide phosphodiesterase type 4 (PDE4), which hydrolyses specifically the second intracellular messenger 3′, 5′-cyclic AMP (cAMP). It must be pointed out that CS might induce PDE4 up-regulation similarly to the COVID-19 inflammation, and therefore could potentiate COVID-19 inflammation opening the potential therapeutic effects of PDE4 inhibitor in both COVID-19-inflammation and CS.

Antibody-Based Immunotherapeutic Strategies for COVID-19

Global efforts to contain the coronavirus disease-2019 (COVID-19) include the development of novel preventive vaccines and effective therapeutics. Passive antibody therapies using convalescent plasma, SARS-CoV-2 (Severe-Acute-Respiratory-Syndrome-Corona-Virus-2)-specific neutralizing antibodies (NAbs), and the development of monoclonal antibodies (MAbs) are among the most promising strategies for prophylaxis and treatment of SARS-CoV-2 infections. In addition, several immunomodulatory antibodies acting via several mechanisms to boost the host immune defense against SARS-CoV-2 infection as well as to avoid the harmful overreaction of the immune system are currently under clinical trial. Our main objective is to present the current most up-to-date progress in some clinical trials registered at ClinicalTrials.gov. We highlight the pros and pitfalls of several SARS-CoV-2 antibody-based immunotherapeutics.