Lasting Immunity Research Articles

Advances in Leishmania Vaccines: Current Development and Future Prospects.

Leishmaniasis is a neglected tropical disease caused by parasites of the genus Leishmania. As approved human vaccines are not available, treatment and prevention rely heavily on toxic chemotherapeutic agents, which face increasing resistance problems. The development of effective vaccines against human leishmaniasis is of utmost importance for the control of the disease. Strategies that have been considered for this purpose range from whole-killed and attenuated parasites to recombinant proteins and DNA vaccines. The ideal vaccine must be safe and effective, ensuring lasting immunity through a robust IL-12-driven Th1 adaptive immune response. Despite some success and years of effort, human vaccine trials have encountered difficulties in conferring durable protection against Leishmania, a problem that may be attributed to the parasite's antigenic diversity and the intricate nature of the host's immune response. The aim of this review is to provide a thorough overview of recent advances in Leishmania vaccine development, ranging from initial trials to recent achievements, such as the ChAd63-KH DNA vaccine, which underscores the potential for effective control of leishmaniasis through continued research in this field.

The challenge of generating lasting mucosal anti-viral sterilising immunity

The challenge of generating lasting mucosal anti-viral sterilising immunity Achieving sterilising immunity is often challenging and sometimes even impossible. This article gives a glimpse into the concepts behind and highlights some recent advances and challenges. In its essence, sterilising immunity describes the removal of a virus from the host before it can replicate, and this kind of immunity would be the preferred outcome for vaccination as it efficiently limits the infection of the individual and the spread of disease within the community. A typical viral infection goes through a four-step cycle: first, the virus attaches to and enters a host cell; second, it copies its genetic material; third, it assembles new viral particles; and finally, it detaches to infect new cells. In its most straightforward form, sterilising immunity is achieved by the neutralisation of the infectious potential in the first step, (Wahl and Wardemann, Immunity, 2022) followed by their removal.

Prediction of an immunogenic peptide ensemble and multi-subunit vaccine for Visceral leishmaniasis using bioinformatics approaches

Visceral Leishmaniasis (VL) is a neglected tropical disease of public health importance in the Indian subcontinent. Despite consistent elimination initiatives, the disease has not yet been eliminated and there is an increased risk of resurgence from active VL reservoirs including asymptomatic, post kala azar dermatitis leishmaniasis (PKDL) and HIV-VL co-infected individuals. To achieve complete elimination and sustain it in the long term, a prophylactic vaccine, which can elicit long lasting immunity, is desirable. In this study, we employed immunoinformatic tools to design a multi-subunit epitope vaccine for the Indian population by targeting antigenic secretory proteins screened from the Leishmania donovani proteome. Out of 8014 proteins, 277 secretory proteins were screened for their cellular location and proteomic evidence. Through NCBI BlastP, unique fragments of the proteins were cropped, and their antigenicity was evaluated. B-cell, HTL and CTL epitopes as well as IFN-ɣ, IL-17, and IL-10 inducers were predicted, manually mapped to the fragments and common regions were tabulated forming a peptide ensemble. The ensemble was evaluated for Class I MHC immunogenicity and toxicity. Further, immunogenic peptides were randomly selected and used to design vaccine constructs. Eight vaccine constructs were generated by linking random peptides with GS linkers. Synthetic TLR-4 agonist, RS09 was used as an adjuvant and linked with the constructs using EAAK linkers. The predicted population coverage of the constructs was ∼99.8 % in the Indian as well as South Asian populations. The most antigenic, nontoxic, non-allergic construct was chosen for the prediction of secondary and tertiary structures. The 3D structures were refined and analyzed using Ramachandran plot and Z-scores. The construct was docked with TLR-4 receptor. Molecular dynamic simulation was performed to check for the stability of the docked complex. Comparative in silico immune simulation studies showed that the predicted construct elicited humoral and cell-mediated immunity in human host comparable to that elicited by Leish-F3, which is a promising vaccine candidate for human VL.

Both Humoral and Cellular Immune Responses to SARS-CoV-2 Are Essential to Prevent Infection: a Prospective Study in a Working Vaccinated Population from Southern France

COVID-19 vaccines have significantly decreased the number of severe cases of the disease, but the virus circulation remains important, and questions about the need of new vaccination campaigns remain unanswered. The individual’s protection against SARS-CoV-2 infection is most commonly measured by the level and the neutralizing capacity of antibodies produced against SARS-CoV-2. T cell response is a major contributor in viral infection, and several studies have shown that cellular T cell response is crucial in fighting off SARS-CoV-2 infection. Actually, no threshold of protective immune response against SARS-CoV2 infection has been identified. To better understand SARS-CoV-2-mediated immunity, we assessed both B cell (measuring anti-Spike IgG titer and neutralization capacity) and T cell (measuring IFNγ release assay after specific SARS-CoV2 stimulation) responses to SARS-CoV-2 vaccination with or without virus encounter in a cohort of 367 working volunteers. Vaccinated individuals who had previously been infected had a stronger and more lasting immunity in comparison to vaccinated individuals naive to infection whose immunity started to decline 3 months after vaccination. IFNγ release ≥ 0.285 IU/mL and anti-Spike IgG antibodies ≥ 244 BAU/mL were associated with a sufficient immune response following vaccination preventing future infections. Individuals with comorbidities had a lower chance of reaching the protective thresholds of T cell and B cell responses as identified in multivariate analysis. A combined B cell and T cell analysis of immune responses to determine protective thresholds after SARS-CoV-2 vaccination will allow us to identify individuals in need of a booster vaccine dose, particularly in comorbid subjects.

Onset of Protection of FeLV Vaccine Containing Purified P45 FeLV-Envelope Antigen after One Single Injection of Primary Vaccination in Cats

Feline Leukaemia Virus (FeLV) is a viral pathogen causing fatal disease in cat populations worldwide, mainly in young kittens with outdoor access. This study aimed to assess the protection against feline leukaemia virus (FeLV), provided by a FeLV vaccine containing purified p45 FeLV-envelope antigen (Leucogen®) after one single injection of primary vaccination in kittens. Twenty-five 9-week-old cats, negative for FeLV antibodies and antigens the day of vaccination, were randomized into two groups. One group of 10 kittens was not vaccinated and kept as control, and one group of 15 animals received one dose of Leucogen® vaccine. The serological response was measured 14 and 21 days post vaccination. Three weeks after the vaccination, all kittens were inoculated by oronasal route with a virulent FeLV-A strain. The development of persistent viraemia was monitored for 15 weeks following inoculation. The animals were clinically monitored closely during the experimental phase. All cats remained in good health, presented physiological growth along the study and did not show any unexpected reaction after vaccination. In the control group, 90% of cats (9/10 cats) developed a persistent infection, confirming that this experimental infection model was valid, since the minimum of 80% required by the European monograph was achieved. On the other side, 73% of the vaccinated cats (11/15 cats) did not develop a persistent infection following the challenge strain inoculation. In the FeLV vaccinated group, 73% of cats were protected from the first vaccine injection. The first injection of primary vaccination with Leucogen® vaccine provided complete protection against FeLV persistent viraemia in 73% of the kittens. The second injection of the primary vaccination is necessary to ensure a complete protection of the whole population and a long lasting immunity. The early protection against FeLV infection conferred after one single injection of primary vaccination with FeLV vaccine containing purified p45 FeLV-envelope antigen could be a contributing factor in the reduction of prevalence of FeLV infection.

A pair formation model with recovery: Application to mpox

The current global outbreaks of mpox is a unique infectious disease in the way it seems to be transmitting: it has been observed to be highly concentrated in communities of men who have sex with men (MSM) through pair formation, and also provides long lasting immunity. This framework of mostly close, prolonged contact spreading a disease that admits immunity after infection is unlike similar infections which either offer little to no immunity post-infection or are lifelong infections. This creates the need for a new model framework that incorporates pair formation structure with recovery. While seemingly a straight forward model, we show how new dynamics arise from the combination of pair formation and recovery that are not present in a standard model with recovery and also not present in a pair formation model without recovery. We see that the combination of these two properties allows for waves of infection that are not seen in a standard SIR model. These dynamics suggest that outbreaks of mpox around the world may require special attention from public health. We also derive a reproduction number for this model and estimate the reproduction number of human mpox to be ≈2.3 using global and Canadian data. The expression derived for R0 can help estimate key parameters for diseases transmission and public health interventions and compare to equivalent models without pair formation.

Intranasal delivery of an adenovirus-vector vaccine co-expressing a modified spike protein and a genetic adjuvant confers lasting mucosal immunity against SARS-CoV-2

The ongoing COVID-19 pandemic caused by SARS-CoV-2 infection has threatened global health. Since the first case of infection was reported in December 2019, SARS-CoV-2 has rapidly spread worldwide and caused millions of deaths. As vaccination is the best way to protect the host from invading pathogens, several vaccines have been developed to prevent the infection of SARS-CoV-2, saving numerous lives thus far. However, SARS-CoV-2 constantly changes its antigens, resulting in escape from vaccine-induced protection, and the longevity of immunity induced by vaccines remains an issue. Additionally, traditional intramuscular COVID-19 vaccines are insufficient at evoking mucosal-specific immune responses. Because the respiratory tract is the primary route of SARS-CoV-2 entry, the need for mucosal vaccines is strong. Using an adenoviral (Ad) vector platform, we generated Ad5-S.Mod, a recombinant COVID-19 vaccine that encodes modified-spike (S) antigen and the genetic adjuvant human CXCL9. Intranasal delivery of Ad5-S.Mod elicited superior airway humoral and T-cell responses over traditional intramuscular vaccines and protected mice from lethal SARS-CoV-2 infection. cDC1 cells were required for the generation of antigen-specific CD8+ T-cell responses and CD8+ tissue-resident memory T-cell development in intranasal Ad5-S.Mod vaccinated mice. Furthermore, we confirmed the efficacy of the intranasal Ad5-S.Mod vaccine in terms of transcriptional changes and identified lung macrophages as a key supporter of maintenance of lung-resident memory T and B cells. Our study demonstrates Ad5-S.Mod has the potential to confer protective immunity against SARS-CoV-2 and that lung macrophages support the maintenance of vaccine-induced tissue-resident memory lymphocytes.

Combination of High-Resolution Structures for the B Cell Receptor and Co-Receptors Provides an Understanding of Their Interactions with Therapeutic Antibodies.

B cells are central to the adaptive immune response, providing long lasting immunity after infection. B cell activation is mediated by a cell surface B cell receptor (BCR) following recognition of an antigen. BCR signaling is modulated by several co-receptors including CD22 and a complex that contains CD19 and CD81. Aberrant signaling through the BCR and co-receptors promotes the pathogenesis of several B cell malignancies and autoimmune diseases. Treatment of these diseases has been revolutionized by the development of monoclonal antibodies that bind to B cell surface antigens, including the BCR and its co-receptors. However, malignant B cells can escape targeting by several mechanisms and until recently, rational design of antibodies has been limited by the lack of high-resolution structures of the BCR and its co-receptors. Herein we review recently determined cryo-electron microscopy (cryo-EM) and crystal structures of the BCR, CD22, CD19 and CD81 molecules. These structures provide further understanding of the mechanisms of current antibody therapies and provide scaffolds for development of engineered antibodies for treatment of B cell malignancies and autoimmune diseases.

PAWG pilot study on quantification of SARS-CoV-2 monoclonal antibody - Part 2

Main textUnder the auspices of the Protein Analysis Working Group (PAWG) of the Comité Consultatif pour la Quantité de Matière (CCQM) a pilot study, CCQM-P216, was coordinated by the Chinese National Institute of Metrology (NIM), National Research Council of Canada (NRC) and the Bureau International des Poids et Mesures (BIPM).The global coronavirus pandemic has also led to increased focus on antibody quantitation methods. IgG are among the immunoglobulins produced by the immune system to provide protection against SARS-CoV-2. Anti-SARS-CoV-2 IgG can therefore be detected in samples from affected patients. Antibody tests can show whether a person has been exposed to SARS-CoV-2, and whether or not they potentially show lasting immunity to the disease. With the constant spread of the virus and the high pressure of re-opening economies, antibody testing played a critical role in the fight against COVID-19 by helping healthcare professionals to identify individuals who have developed an immune response, either via vaccination or exposure to the virus. Many countries have launched large-scale antibody testing for COVID-19. The development of measurement standards for the antibody detection of SARS-CoV-2 is critically important to deal with the challenges of the COVID-19 pandemic. In this study, the SARS-CoV-2 monoclonal antibody is being used as a model system to build capacity in methods that can be used in antibody quantification.The purpose of this pilot study was to develop measurement capabilities for larger proteins using a recombinant humanized IgG monoclonal antibody against Spike glycoprotein of SARS-CoV-2 (Anti-S IgG mAb) in solution. A Final Report on the first round of CCQM-P216 PAWG Pilot Study on Quantification of SARS-CoV-2 Monoclonal Antibody - Part 1 focusing on the assessment of both mass fraction determinations of different AAs in the material and mass fraction determinations of proteotypic peptides belonging to the constant region of the mAb has already been published in Metrologia. The present Final Report on the second round of CCQM-P216 - Part 2 was designed to investigate optional methods for the characterization of Anti-S IgG mAb in solution for the assessment of size heterogeneity purity determinations, mass fraction measurements of SARS-CoV-2 monoclonal antibody in the material by UV-VIS spectrophotometry, mass fraction measurements of proteotypic peptides belonging to the variable region of the mAb and mass fraction measurements of monomeric mAb in the material. Six Metrology Institutes or Designated Institutes and the BIPM participated in the second phase of the pilot study (Part 2).Acceptable agreement between all laboratories was for the assessment of size heterogeneity of the anti-S IgG mAb material. For example, a reference value with its corresponding expanded uncertainties of (99.48 ± 0.49) % has been obtained for the monomer. Good between laboratories for UV-VIS spectrophotometric analysis at a pre-agreed wavelength of 280 nm was obtained with individual relative expanded uncertainties from 2.8 % to 15.5 % and a mass concentration reference value and corresponding expanded uncertainty of (500.8 ± 15.4) mg/L.Mass fraction assignments of the target proteotypic peptide YSPSFQGQVTISADK in the variable region of the anti-S IgG mAb material by NIM and BIPM resulted in a reference value and corresponding expanded uncertainty of (9.8 ± 2.0) mg/kg.Both NIM and BIPM have provided estimates for the mass fraction of monomeric mAb in the material with individual relative expanded uncertainties of 4.3 % and 4.1 %, respectively. A mass fraction reference value and corresponding expanded uncertainty of (411 ± 88) mg/kg was calculated by applying an 'excess-variance' approach for the monomeric mAb mass fraction.In addition, a post-hoc assessment of the monomeric mAb mass fraction from the subset of that produced both amino acid and proteotypic peptide-based mass fraction results and SEC measurements during the 1st and present study round provided more detailed information. A reference value and its expanded uncertainty for the mass fraction of monomeric mAb in the anti-S IgG mAb material was calculated to be (434.3 ± 11.9) mg/kg applying an 'excess-variance' approach.The level of agreement was not significantly poorer than that achieved in previous studies with smaller or less complex proteins. The two-stage pilot study was a big step forward to build and improve capacity within NMIs/DIs to undertake future key comparisons in the field of mass fraction determinations of antibodies and other large proteins.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

How to employ metabolomic analysis to research on functions of prebiotics and probiotics in poultry gut health?

Gut health can be considered one of the major, manageable constituents of the animal immunity and performance. The fast spread of intestinal diseases, and increase of antimicrobial resistance have been observed, therefore the intestinal health has become not only economically relevant, but also highly important subject addressing the interest of public health. It is expected, that the strategies to control infections should be based on development of natural immunity in animals and producing resilient flocks using natural solutions, whilst eliminating antibiotics and veterinary medicinal products from action. Probiotics and prebiotics have been favored, because they have potential to directly or indirectly optimize intestinal health by manipulating the metabolism of the intestinal tract, including the microbiota. Studying the metabolome of probiotics and gut environment, both in vivo, or using the in vitro models, is required to attain the scientific understanding about the functions of bioactive compounds in development of gut health and life lasting immunity. There is a practical need to identify new metabolites being the key bioactive agents regulating biochemical pathways of systems associated with gut (gut-associated axes). Technological advancement in metabolomics studies, and increasing access to the powerful analytical platforms have paved a way to implement metabolomics in exploration of the effects of prebiotics and probiotics on the intestinal health of poultry. In this article, the basic principles of metabolomics in research involving probiotics and probiotics are introduced, together with the overview of existing strategies and suggestions of their use to study metabolome in poultry.

Demonology, eschatology and vaccinology in African independent Pentecostalism

Public discourses on the reliability of coronavirus disease 2019 (COVID-19) vaccines in dealing with the upsurge of virus cases and deaths are developing and ongoing in many different contexts, as countries around the world are doing their best to build high and lasting immunity. This article worked within the framework of Pentecostal faith and outlined the Pentecostal perspectives on COVID-19 vaccines. The article is a literature analysis on the eschatological view and the demonising of COVID-19 vaccines. In addition, the article analysed the social media utterances of Pentecostal pastors on COVID-19 vaccines. These utterances were obtained from different social media networks, including YouTube. Pentecostal faith has caused some independent Pentecostals in Africa to demonise COVID-19 vaccines and others to perceive them as signs of the end times. While these perceptions appeared as signs of faith in dealing with pandemics such as COVID-19, they have proven fruitless in some instances. Some Pentecostals in Africa have lost their lives due to their insistence on faith, instead of vaccinating against the virus and observing regulations and restrictions. This calls for scholars to revisit a Pentecostal faith in health issues by bringing the balance between works and faith.Contribution: This article is an interdisciplinary study on demonology, eschatology, and vaccinology within African Independent Pentecostalism. The article problematised the demonisation of vaccines and perception of vaccines as signs of end times. The article proposes a Pentecostal faith that balances people’s beliefs and the role of medicine in the provision of healing.

The impact of the suppression of highly connected protein interactions on the corona virus infection

Several highly effective Covid-19 vaccines are in emergency use, although more-infectious coronavirus strains, could delay the end of the pandemic even further. Because of this, it is highly desirable to develop fast antiviral drug treatments to accelerate the lasting immunity against the virus. From a theoretical perspective, computational approaches are useful tools for antiviral drug development based on the data analysis of gene expression, chemical structure, molecular pathway, and protein interaction mapping. This work studies the structural stability of virus–host interactome networks based on the graphical representation of virus–host protein interactions as vertices or nodes connected by commonly shared proteins. These graphical network visualization methods are analogous to those use in the design of artificial neural networks in neuromorphic computing. In standard protein-node-based network representation, virus–host interaction merges with virus–protein and host–protein networks, introducing redundant links associated with the internal virus and host networks. On the contrary, our approach provides a direct geometrical representation of viral infection structure and allows the effective and fast detection of the structural robustness of the virus–host network through proteins removal. This method was validated by applying it to H1N1 and HIV viruses, in which we were able to pinpoint the changes in the Interactome Network produced by known vaccines. The application of this method to the SARS-CoV-2 virus–host protein interactome implies that nonstructural proteins nsp4, nsp12, nsp16, the nuclear pore membrane glycoprotein NUP210, and ubiquitin specific peptidase USP54 play a crucial role in the viral infection, and their removal may provide an efficient therapy. This method may be extended to any new mutations or other viruses for which the Interactome Network is experimentally determined. Since time is of the essence, because of the impact of more-infectious strains on controlling the spread of the virus, this method may be a useful tool for novel antiviral therapies.

Thymic Stromal Lymphopoietin Induction Suppresses Lung Cancer Development.

Simple SummaryThe recurrence rate for lung cancer is high after the removal of the primary tumor. Herein, we demonstrate the potential of immunotherapy against lung cancer by examining the impact of Thymic Stromal Lymphopoietin (TSLP) cytokine induction on early lung cancer development. TSLP induction suppresses the development of invasive lung tumors in a mouse model of spontaneous lung cancer. This cancer suppression is dependent on CD4+ T cells, which highlights the role of adaptive immune response in protection against lung cancer progression.Lung cancer is the leading cause of cancer deaths in the United States and across the world. Immunotherapies, which activate tumor-infiltrating cytotoxic T lymphocytes, have demonstrated efficacy for the treatment of advanced-stage lung cancer. However, the potential for harnessing the immune system against the early stages of lung carcinogenesis to prevent cancer development and recurrence remains unexplored. Using a mouse model of lung adenocarcinoma, we investigated the effects of thymic stromal lymphopoietin (TSLP) induction on early cancer development in the lungs. Herein, we demonstrate that systemic TSLP induction suppressed spontaneous lung cancer development in KrasG12D mice. TSLP drove a significant CD4+ T cell response to block lung cancer progression from atypical alveolar hyperplasia to adenocarcinoma. Our findings suggest that TSLP can be used in the early stages of lung cancer development to trigger a lasting immunity in the tissue and prevent the development of advanced disease.

COVID-19 Pandemic and Diabetes Care.

COVID-19 Pandemic and Diabetes Care.

COVID-19 Infection May Not Produce Lasting Immunity in Non-vaccinated Young Adults: A Retrospective Review of COVID-19 Antibody Data.

BackgroundDespite progress in achieving herd immunity through recovery from previous infection and vaccination efforts, the COVID-19 pandemic continues to be an imminent health concern. Exposure to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral antigen through infection or vaccination facilitates immune system efficacy against future infection, but it is currently unclear how long this immunity lasts. Therefore, understanding the necessary exposures to produce adequate antibody levels and the duration of this humoral response to prevent infection is imperative in updating guidelines for vaccination and ultimately ending this public health crisis. AimsThis study aimed to compare the presence of serum antibodies in younger and older age groups to determine how vaccination and previous infection compare as indicators of immunity against COVID-19. We also evaluated age to determine its role in antibody presence. We hope that this information will be helpful to the public to develop the best recommendations for vaccination guidelines concerning distinct demographics. ​Materials and methodsIn this retrospective data analysis, we evaluated saliva SARS-CoV-2 test results taken from 309 subjects (192F/117M; median age=53.4) during a community fair in Crawford County, PA. We sorted the subjects into groups based on age, reported infection with the COVID-19 virus, and vaccination status. We then performed a Chi-square analysis to compare the frequency of positive SARS-CoV-2 antibody tests within these groups.ResultsThe vaccinated but not previously-infected cohort (n=146, 81.5%) was significantly more likely to have antibodies than the unvaccinated infected cohort (n=55, 65.5%; p<0.0001). In the previously-infected, unvaccinated cohort, individuals who were 55 and older were more likely to have antibodies than younger individuals (p<0.0157), but no age-dependent difference was observed among vaccinated individuals.ConclusionsThe results suggest that vaccination provides a more durable immune response than recovery from infection, and there is an age-dependent humoral response following previous infection but not vaccination. Practically speaking, this information implies that despite popular misconception, individuals under the age of 55 must receive a COVID-19 vaccine despite the previous infection as they are significantly less likely to have antibodies following infection than their counterparts who are over the age of 55.

Long lasting immunity in trichinellosis - insight from a small study group.

Trichinellosis in humans is most often caused by the parasite Trichinella spiralis. The clinical course of the disease is diverse and the symptoms can vary from mild to severe. Symptoms usually disappear within a few months, but encysted larvae in the muscles can cause myalgia and weakness that last for years. However, the existence of chronic trichinellosis as a disease is still debatable. This study presents the results obtained at the National Reference Laboratory for Trichinellosis - INEP, Serbia. The study was conducted to assess the immunoserological, biochemical and symptomatic disease parameters of twelve patients who acquired trichinellosis 13 and 18 years ago, respectively. They were involved in two T. spiralis outbreaks in Serbia, at the village of Kumane and the city of Belgrade (nine and three patients, respectively). Results indicated the presence of specific anti-Trichinella antibodies in 83% of the total number of patients. However, while the humoral immune response to Trichinella lasted for more than a decade reaching almost two decades after the acute infection phase (7/9 and 3/3 respectively, in two outbreaks), persistence of chronic muscular pain, as the most prolonged symptom of trichinellosis, could be found in the majority of patients from the Kumane outbreak (7/9). As a consequence, these patients suffered from limitations in daily living activities for the same period of time. The results presented in this paper are our contribution to the view that trichinellosis as a chronic disease with symptoms exists and may be related to the severity of the disease in the acute phase.

PAWG Pilot Study on Quantification of SARS-CoV-2 Monoclonal Antibody - Part 1

Main textUnder the auspices of the Protein Analysis Working Group (PAWG) of the Comité Consultatif pour la Quantité de Matière (CCQM) a pilot study, CCQM-P216, was coordinated by the Chinese National Institute of Metrology (NIM), National Research Council of Canada (NRC) and the Bureau International des Poids et Mesures (BIPM). Eleven Metrology Institutes or Designated Institutes and the BIPM participated in the first phase of the pilot study (Part 1). The purpose of this pilot study was to develop measurement capabilities for larger proteins using a recombinant humanized IgG monoclonal antibody against Spike glycoprotein of SARS-CoV-2 (Anti-S IgG mAb) in solution. The first phase of the study was designed to employ established methods that had been previously studies by the CCQM Protein Analysis Working Group, involving the digestion of protein down to the peptide or amino acid level.The global coronavirus pandemic has also led to increased focus on antibody quantitation methods. IgG are among the immunoglobulins produced by the immune system to provide protection against SARS-CoV-2. Anti-SARS-CoV-2 IgG can therefore be detected in samples from affected patients. Antibody tests can show whether a person has been exposed to the SARS-CoV-2, and whether or not they potentially show lasting immunity to the disease. With the constant spread of the virus and the high pressure of re-opening economies, antibody testing plays a critical role in the fight against COVID-19 by helping healthcare professionals to identify individuals who have developed an immune response, either via vaccination or exposure to the virus. Many countries have launched large-scale antibody testing for COVID-19. The development of measurement standards for the antibody detection of SARS-CoV-2 is critically important to deal with the challenges of the COVID-19 pandemic. In this study, the SARS-CoV-2 monoclonal antibody is being used as a model system to build capacity in methods that can be used in antibody quantification. Amino acid reference values with corresponding expanded uncertainty of 36.10 ± 1.55 mg/kg, 38.75 ± 1.45 mg/kg, 18.46 ± 0.78 mg/kg, 16.20 ± 0.67 mg/kg and 30.61 ± 1.30 mg/kg have been established for leucine, valine, phenylalanine, isoleucine and proline, respectively. Agreement between nearly all laboratories was achieved for the amino acid analysis within 2 to 2.5 %, with one participant achieving markedly higher results due to a technical issue found in their procedure; this result was thus excluded from the reference value calculations. The relatively good agreement within a laboratory between different amino acids was not dissimilar to previous results for peptides or small proteins, indicating that factors such as hydrolysis conditions and calibration procedures could be the largest sources of variability.Peptide reference values with corresponding expanded uncertainty of 4.99 ± 0.28 mg/kg and 6.83 ± 0.65 mg/kg have been established for ALPAPIEK and GPSVFPLAPSSK, respectively. Not surprisingly due to prior knowledge from previous studies on peptide quantitation, agreement between laboratories for the peptide-based analysis was slightly poorer at 3 to 5 %, with one laboratory's result excluded for the peptide GPSVFPLAPSSK. Again, this level of agreement was not significantly poorer than that achieved in previous studies with smaller or less complex proteins.To reach the main text of this paper, click on Final Report.

Novel virus-like nanoparticle vaccine effectively protects animal model from SARS-CoV-2 infection.

The key to battling the COVID-19 pandemic and its potential aftermath is to develop a variety of vaccines that are efficacious and safe, elicit lasting immunity, and cover a range of SARS-CoV-2 variants. Recombinant viral receptor-binding domains (RBDs) are safe vaccine candidates but often have limited efficacy due to the lack of virus-like immunogen display pattern. Here we have developed a novel virus-like nanoparticle (VLP) vaccine that displays 120 copies of SARS-CoV-2 RBD on its surface. This VLP-RBD vaccine mimics virus-based vaccines in immunogen display, which boosts its efficacy, while maintaining the safety of protein-based subunit vaccines. Compared to the RBD vaccine, the VLP-RBD vaccine induced five times more neutralizing antibodies in mice that efficiently blocked SARS-CoV-2 from attaching to its host receptor and potently neutralized the cell entry of variant SARS-CoV-2 strains, SARS-CoV-1, and SARS-CoV-1-related bat coronavirus. These neutralizing immune responses induced by the VLP-RBD vaccine did not wane during the two-month study period. Furthermore, the VLP-RBD vaccine effectively protected mice from SARS-CoV-2 challenge, dramatically reducing the development of clinical signs and pathological changes in immunized mice. The VLP-RBD vaccine provides one potentially effective solution to controlling the spread of SARS-CoV-2.

SARS-CoV-2 seroconversions and chains of infection in healthcare professionals in a German maximum care provider (The CoSHeP study)

IntroductionThe CoSHeP study provides novel data on SARS-CoV-2 seroconversion rates in healthcare professionals (HP) at risk at the University Hospital Bonn, a maximum healthcare provider in a region of 900.000 inhabitants.MethodsSingle-center, longitudinal observational study investigating rate of SARS-CoV-2 IgG seroconversion in HP at 2 time-points. SARS-CoV-2 IgG was measured with Roche Elecsys Anti-SARS-CoV-2 assay.ResultsOverall, 150 HP were included. Median age was 35 (range: 19–68). Main operational areas were intensive care unit (53%, n = 80), emergency room (31%, n = 46), and infectious disease department (16%, n = 24). SARS-CoV-2-IgG was detected in 5 participants (3%) at inclusion in May/June 2020, and in another 11 participants at follow-up (December 2020/ January 2021). Of the 16 seropositive participants, 14 had already known their SARS-CoV-2 infection because they had performed a PCR-test previously triggered by symptoms. Trailing chains of infection by self-assessment, 31% (n = 5) of infections were acquired through private contacts, 25% (n = 4) most likely through semi-private contacts during work. 13% (n = 2) were assumed to result through contact with contagious patients, further trailing was unsuccessful in 31% (n = 5). All five participants positive for SARS-CoV-2 IgG at inclusion remained positive with a median of 7 months after infection.DiscussionFrontline HP caring for hospitalized patients with COVID-19 are at higher risk of SARS-CoV-2 infections. Noteworthy, based upon identified chains of infection most of the infections were acquired in private environment and semi-private contacts during work. The low rate of infection through infectious patients reveals that professional hygiene standards are effective in preventing SARS-CoV-2 infections in HP. Persisting SARS-CoV-2-IgG might indicate longer lasting immunity supporting prioritization of negative HP for vaccination.

Serological identification of past and recent SARS-CoV-2 infection through antibody screening in Luanda, Angola.

Serological identification of past and recent SARS-CoV-2 infection through antibody screening in Luanda, Angola.