Control of SARS-CoV-2 infection after Spike DNA or Spike DNA+Protein co-immunization in rhesus macaques

Emerging Trends of Gold Nanostructures for Point-of-Care Biosensor-Based Detection of COVID-19

In 2019, a worldwide pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged. SARS-CoV-2 is the deadly microorganism responsible for coronavirus disease 2019 (COVID-19), which has caused millions of deaths and irreversible health problems worldwide. To restrict the spread of SARS-CoV-2, accurate detection of COVID-19 is essential for the identification and control of infected cases. Although recent detection technologies such as the real-time polymerase chain reaction delivers an accurate diagnosis of SARS-CoV-2, they require a long processing duration, expensive equipment, and highly skilled personnel. Therefore, a rapid diagnosis with accurate results is indispensable to offer effective disease suppression. Nanotechnology is the backbone of current science and technology developments including nanoparticles (NPs) that can biomimic the corona and develop deep interaction with its proteins because of their identical structures on the nanoscale. Various NPs have been extensively applied in numerous medical applications, including implants, biosensors, drug delivery, and bioimaging. Among them, point-of-care biosensors mediated with gold nanoparticles (GNPSs) have received great attention due to their accurate sensing characteristics, which are widely used in the detection of amino acids, enzymes, DNA, and RNA in samples. GNPS have reconstructed the biomedical application of biosensors because of its outstanding physicochemical characteristics. This review provides an overview of emerging trends in GNP-mediated point-of-care biosensor strategies for diagnosing various mutated forms of human coronaviruses that incorporate different transducers and biomarkers. The review also specifically highlights trends in gold nanobiosensors for coronavirus detection, ranging from the initial COVID-19 outbreak to its subsequent evolution into a pandemic.

Rapid transient and longer-lasting innate cytokine changes associated with adaptive immunity after repeated SARS-CoV-2 BNT162b2 mRNA vaccinations

Introduction

Cytokines and chemokines play an important role in shaping innate and adaptive immunity in response to infection and vaccination. Systems serology identified immunological parameters predictive of beneficial response to the BNT162b2 mRNA vaccine in COVID-19 infection-naïve volunteers, COVID-19 convalescent patients and transplant patients with hematological malignancies. Here, we examined the dynamics of the serum cytokine/chemokine responses after the 3rd BNT162b2 mRNA vaccination in a cohort of COVID-19 infection-naïve volunteers.

Methods

We measured serum cytokine and chemokine responses after the 3rd dose of the BNT162b2 mRNA (Pfizer/BioNtech) vaccine in COVID-19 infection-naïve individuals by a chemiluminescent assay and ELISA. Anti-Spike binding antibodies were measured by ELISA. Anti-Spike neutralizing antibodies were measured by a pseudotype assay.

Results

Comparison to responses found after the 1st and 2nd vaccinations showed persistence of the coordinated responses of several cytokine/chemokines including the previously identified rapid and transient IL-15, IFN-γ, CXCL10/IP-10, TNF-α, IL-6 signature. In contrast to the transient (24hrs) effect of the IL-15 signature, an inflammatory/anti-inflammatory cytokine signature (CCL2/MCP-1, CCL3/MIP-1α, CCL4/MIP-1β, CXCL8/IL-8, IL-1Ra) remained at higher levels up to one month after the 2nd and 3rd booster vaccinations, indicative of a state of longer-lasting innate immune change. We also identified a systemic transient increase of CXCL13 only after the 3rd vaccination, supporting stronger germinal center activity and the higher anti-Spike antibody responses. Changes of the IL-15 signature, and the inflammatory/anti-inflammatory cytokine profile correlated with neutralizing antibody levels also after the 3rd vaccination supporting their role as immune biomarkers for effective development of vaccine-induced humoral responses.

Conclusion

These data revealed that repeated SARS-Cov-2 BNT162b2 mRNA vaccination induces both rapid transient as well as longer-lasting systemic serum cytokine changes associated with innate and adaptive immune responses.

Clinical trial registration

Clinicaltrials.gov, identifier NCT04743388.

Co-delivery of a trimeric spike DNA and protein vaccine with aluminum hydroxide enhanced Th1-dominant humoral and cellular immunity against SARS-CoV-2

Protein subunit vaccines have been used as prophylactic vaccines for a long time. The well-established properties of these vaccines make them the first choice for the coronavirus disease 2019 (COVID-19) outbreak. However, it is not easy to develop a protein vaccine that induces cytotoxic T lymphocyte responses and requires a longer time for manufacturing, which limits the usage of this vaccine type. Here, we report the combination of a recombinant spike (S)-trimer protein with a DNA vaccine-encoded S protein as a novel COVID-19 vaccine. The recombinant S protein was formulated with different adjuvants and mixed with the DNA plasmid before injection. We found that the recombinant S protein formulated with the adjuvant aluminum hydroxide and mixed with the DNA plasmid could enhance antigen-specific antibody titers, neutralizing antibody titers. We further evaluated the IgG2a/IgG1 isotype and cytokine profiles of the specific boosted T-cell response, which indicated that the combined vaccine induced a T-helper 1 cell-biased immune response. Immunized hamsters were challenged with severe acute respiratory syndrome coronavirus 2, and the body weight of the hamsters that received the recombinant S protein with aluminum hydroxide and/or the DNA plasmid was not reduced. Alternatively, those that received control or only the DNA plasmid immunization were reduced. Interestingly, after the third day of the viral load in the lungs, the viral challenge could not be detected in hamsters immunized with the recombinant S protein in aluminum hydroxide mixed with DNA (tissue culture infectious dose < 10). The viral load in the lungs was 109 , 106 , and 107 for the phosphate-buffered saline, protein in aluminum hydroxide, and DNA-only immunizations, respectively. These results indicated that antiviral mechanisms neutralizing antibodies play important roles. Furthermore, we found that the combination of protein and DNA vaccination could induce relatively strong CD8+ T-cell responses. In summary, the protein subunit vaccine combined with a DNA vaccine could induce strong CD8+ T-cell responses to increase antiviral immunity for disease control.

Immunogenicity of the DNA/Protein Combined Vaccine against COVID-19

During the COVID-19 pandemic, the development of prophylactic vaccines, including those based on new platforms, became highly relevant. One such platform is the creation of vaccines combining DNA and protein components in one construct. For the creation of DNA vaccine, we chose the full-length spike protein (S) of the SARS-CoV-2 virus and used the recombinant receptor-binding domain (RBD) of the S protein produced in CHO-K1 cells as a protein component. The immunogenicity of the developed combined vaccine and its individual components was compared and the contribution of each component to the induction of the immune response was analyzed. The combined DNA/protein vaccine possesses the advantages of both underlying approaches and is capable of inducing both humoral (similar to subunit vaccines) and cellular (similar to DNA vaccines) immunity.

Low Spike Antibody Levels and Impaired BA.4/5 Neutralization in Patients with Multiple Myeloma or Waldenstrom's Macroglobulinemia after BNT162b2 Booster Vaccination

Patients with symptomatic monoclonal gammopathies have impaired humoral responses to COVID-19 vaccination. Their ability to recognize SARS-CoV-2 Omicron variants is of concern. We compared the response to BNT162b2 mRNA vaccinations of patients with multiple myeloma (MM, n = 60) or Waldenstrom's macroglobulinemia (WM, n = 20) with healthy vaccine recipients (n = 37). Patient cohorts on active therapy affecting B cell development had impaired binding and neutralizing antibody (NAb) response rate and magnitude, including several patients lacking responses, even after a 3rd vaccine dose, whereas non-B cell depleting therapies had a lesser effect. In contrast, MM and WM cohorts off-therapy showed increased NAb with a broad response range. ELISA Spike-Receptor Binding Domain (RBD) Ab titers in healthy vaccine recipients and patient cohorts were good predictors of the ability to neutralize not only the original WA1 but also the most divergent Omicron variants BA.4/5. Compared to WA1, significantly lower NAb responses to BA.4/5 were found in all patient cohorts on-therapy. In contrast, the MM and WM cohorts off-therapy showed a higher probability to neutralize BA.4/5 after the 3rd vaccination. Overall, the boost in NAb after the 3rd dose suggests that repeat vaccination of MM and WM patients is beneficial even under active therapy.

Optimization of In Vivo Electroporation Conditions and Delivery of DNA Vaccine Encoding SARS-CoV-2 RBD Using the Determined Protocol

Vaccination against SARS-CoV-2 and other viral infections requires safe, effective, and inexpensive vaccines that can be rapidly developed. DNA vaccines are candidates that meet these criteria, but one of their drawbacks is their relatively weak immunogenicity. Electroporation (EP) is an effective way to enhance the immunogenicity of DNA vaccines, but because of the different configurations of the devices that are used for EP, it is necessary to carefully select the conditions of the procedure, including characteristics such as voltage, current strength, number of pulses, etc. In this study, we determined the optimal parameters for delivery DNA vaccine by electroporation using the BEX CO device. BALB/c mice were used as a model. Plasmid DNA phMGFP was intramuscular (I/M) injected into the quadriceps muscle of the left hind leg of animals using insulin syringes, followed by EP. As a result of the experiments, the following EP parameters were determined: direct and reverse polarity rectangular DC current in three pulses, 12 V voltage for 30 ms and 950 ms intervals, with a current limit of 45 mA. The selected protocol induced a low level of injury and provided a high level of GFP expression. The chosen protocol was used to evaluate the immunogenicity of the DNA vaccine encoding the receptor-binding domain (RBD) of the SARS-CoV-2 protein (pVAXrbd) injected by EP. It was shown that the delivery of pVAXrbd via EP significantly enhanced both specific humoral and cellular immune responses compared to the intramuscular injection of the DNA vaccine.

Development of gold nanoparticle-based biosensors for COVID-19 diagnosis

Background

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative organism of coronavirus disease 2019 (COVID-19) which poses a significant threat to public health worldwide. Though there are certain recommended drugs that can cure COVID-19, their therapeutic efficacy is limited. Therefore, the early and rapid detection without compromising the test accuracy is necessary in order to provide an appropriate treatment for the disease suppression.

Main body

Nanoparticles (NPs) can closely mimic the virus and interact strongly with its proteins due to their morphological similarities. NPs have been widely applied in a variety of medical applications, including biosensing, drug delivery, antimicrobial treatment, and imaging. Recently, NPs-based biosensors have attracted great interest for their biological activities and specific sensing properties, which allows the detection of analytes such as nucleic acids (DNA or RNA), aptamers, and proteins in clinical samples. Further, the advances of nanotechnologies have enabled the development of miniaturized detection systems for point-of-care biosensors, a new strategy for detecting human viral diseases. Among the various NPs, the specific physicochemical properties of gold NPs (AuNPs) are being widely used in the field of clinical diagnostics. As a result, several AuNP-based colorimetric detection methods have been developed.

Short conclusion

The purpose of this review is to provide an overview of the development of AuNPs-based biosensors by virtue of its powerful characteristics as a signal amplifier or enhancer that target pathogenic RNA viruses that provide a reliable and effective strategy for detecting of the existing or newly emerging SARS-CoV-2.

T cells in SARS-CoV-2 infection and vaccination

While antibodies garner the lion’s share of attention in SARS-CoV-2 immunity, cellular immunity (T cells) may be equally, if not more important, in controlling infection. Both CD8⁺ and CD4⁺ T cells are elicited earlier and are associated with milder disease, than antibodies, and T-cell activation appears to be necessary for control of infection. Variants of concern (VOCs) such as Omicron have escaped the neutralizing antibody responses after two mRNA vaccine doses, but T-cell immunity is largely intact. The breadth and patient-specific nature of the latter offers a formidable line of defense that can limit the severity of illness, and are likely to be responsible for most of the protection from natural infection or vaccination against VOCs which have evaded the antibody response. Comprehensive searches for T-cell epitopes, T-cell activation from infection and vaccination of specific patient groups, and elicitation of cellular immunity by various alternative vaccine modalities are here reviewed. Development of vaccines that specifically target T cells is called for, to meet the needs of patient groups for whom cellular immunity is weaker, such as the elderly and the immunosuppressed. While VOCs have not yet fully escaped T-cell immunity elicited by natural infection and vaccines, some early reports of partial escape suggest that future VOCs may achieve the dreaded result, dislodging a substantial proportion of cellular immunity, enough to cause a grave public health burden. A proactive, rather than reactive, solution which identifies and targets immutable sequences in SARS-CoV-2, not just those which are conserved, may be the only recourse humankind has to disarm these future VOCs before they disarm us.

Reduced Antibodies and Innate Cytokine Changes in SARS-CoV-2 BNT162b2 mRNA Vaccinated Transplant Patients With Hematological Malignancies

Immunocompromised individuals including patients with hematological malignancies constitute a population at high risk of developing severe disease upon SARS-CoV-2 infection. Protection afforded by vaccination is frequently low and the biology leading to altered vaccine efficacy is not fully understood. A patient cohort who had received bone marrow transplantation or CAR-T cells was studied following a 2-dose BNT162b2 mRNA vaccination and compared to healthy vaccine recipients. Anti-Spike antibody and systemic innate responses were compared in the two vaccine cohorts. The patients had significantly lower SARS-CoV-2 Spike antibodies to the Wuhan strain, with proportional lower cross-recognition of Beta, Delta, and Omicron Spike-RBD proteins. Both cohorts neutralized the wildtype WA1 and Delta but not Omicron. Vaccination elicited an innate cytokine signature featuring IFN-γ, IL-15 and IP-10/CXCL10, but most patients showed a diminished systemic cytokine response. In patients who failed to develop antibodies, the innate systemic response was dominated by IL-8 and MIP-1α with significant attenuation in the IFN-γ, IL-15 and IP-10/CXCL10 signature response. Changes in IFN-γ and IP-10/CXCL10 at priming vaccination and IFN-γ, IL-15, IL-7 and IL-10 upon booster vaccination correlated with the Spike antibody magnitude and were predictive of successful antibody development. Overall, the patients showed heterogeneous adaptive and innate responses with lower humoral and reduced innate cytokine responses to vaccination compared to naïve vaccine recipients. The pattern of responses described offer novel prognostic approaches for potentiating the effectiveness of COVID-19 vaccination in transplant patients with hematological malignancies.

Sequential Analysis of Binding and Neutralizing Antibody in COVID-19 Convalescent Patients at 14 Months After SARS-CoV-2 Infection

Durability of SARS-CoV-2 Spike antibody responses after infection provides information relevant to understanding protection against COVID-19 in humans. We report the results of a sequential evaluation of anti-SARS-CoV-2 antibodies in convalescent patients with a median follow-up of 14 months (range 12.4-15.4) post first symptom onset. We report persistence of antibodies for all four specificities tested [Spike, Spike Receptor Binding Domain (Spike-RBD), Nucleocapsid, Nucleocapsid RNA Binding Domain (N-RBD)]. Anti-Spike antibodies persist better than anti-Nucleocapsid antibodies. The durability analysis supports a bi-phasic antibody decay with longer half-lives of antibodies after 6 months and antibody persistence for up to 14 months. Patients infected with the Wuhan (WA1) strain maintained strong cross-reactive recognition of Alpha and Delta Spike-RBD but significantly reduced binding to Beta and Mu Spike-RBD. Sixty percent of convalescent patients with detectable WA1-specific NAb also showed strong neutralization of the Delta variant, the prevalent strain of the present pandemic. These data show that convalescent patients maintain functional antibody responses for more than one year after infection, suggesting a strong long-lasting response after symptomatic disease that may offer a prolonged protection against re-infection. One patient from this cohort showed strong increase of both Spike and Nucleocapsid antibodies at 14 months post-infection indicating SARS-CoV-2 re-exposure. These antibodies showed stronger cross-reactivity to a panel of Spike-RBD including Beta, Delta and Mu and neutralization of a panel of Spike variants including Beta and Gamma. This patient provides an example of strong anti-Spike recall immunity able to control infection at an asymptomatic level. Together, the antibodies from SARS-CoV-2 convalescent patients persist over 14 months and continue to maintain cross-reactivity to the current variants of concern and show strong functional properties.