A Pfs48/45-based vaccine to block Plasmodium falciparum transmission: phase 1, open-label, clinical trial.

BACKGROUND: The stalling global progress in malaria control highlights the need for novel tools for malaria elimination, including transmission-blocking vaccines. Transmission-blocking vaccines aim to induce human antibodies that block parasite development in the mosquito and mosquitoes becoming infectious. The Pfs48/45 protein is a leading Plasmodium falciparum transmission-blocking vaccine candidate. The R0.6C fusion protein, consisting of Pfs48/45 domain 3 (6C) and the N-terminal region of P. falciparum glutamate-rich protein (R0), has previously been produced in Lactococcus lactis and elicited functional antibodies in rodents. Here, we assess the safety and transmission-reducing efficacy of R0.6C adsorbed to aluminium hydroxide with and without Matrix-M™ adjuvant in humans. METHODS: In this first-in-human, open-label clinical trial, malaria-naïve adults, aged 18-55 years, were recruited at the Radboudumc in Nijmegen, the Netherlands. Participants received four intramuscular vaccinations on days 0, 28, 56 and 168 with either 30 µg or 100 µg of R0.6C and were randomised for the allocation of one of the two different adjuvant combinations: aluminium hydroxide alone, or aluminium hydroxide combined with Matrix-M1™ adjuvant. Adverse events were recorded from inclusion until 84 days after the fourth vaccination. Anti-R0.6C and anti-6C IgG titres were measured by enzyme-linked immunosorbent assay. Transmission-reducing activity of participants' serum and purified vaccine-specific immunoglobulin G was assessed by standard membrane feeding assays using laboratory-reared Anopheles stephensi mosquitoes and cultured P. falciparum gametocytes. RESULTS: Thirty-one participants completed four vaccinations and were included in the analysis. Administration of all doses was safe and well-tolerated, with one related grade 3 adverse event (transient fever) and no serious adverse events occurring. Anti-R0.6C and anti-6C IgG titres were similar between the 30 and 100 µg R0.6C arms, but higher in Matrix-M1™ arms. Neat participant sera did not induce significant transmission-reducing activity in mosquito feeding experiments, but concentrated vaccine-specific IgGs purified from sera collected two weeks after the fourth vaccination achieved up to 99% transmission-reducing activity. CONCLUSIONS: R0.6C/aluminium hydroxide with or without Matrix-M1™ is safe, immunogenic and induces functional Pfs48/45-specific transmission-blocking antibodies, albeit at insufficient serum concentrations to result in transmission reduction by neat serum. Future work should focus on identifying alternative vaccine formulations or regimens that enhance functional antibody responses. TRIAL REGISTRATION: The trial is registered with ClinicalTrials.gov under identifier NCT04862416.

CpG-adjuvanted stable prefusion SARS-CoV-2 spike protein protected hamsters from SARS-CoV-2 challenge.

The COVID-19 pandemic presents an unprecedented challenge to global public health. Rapid development and deployment of safe and effective vaccines are imperative to control the pandemic. In the current study, we applied our adjuvanted stable prefusion SARS-CoV-2 spike (S-2P)-based vaccine, MVC-COV1901, to hamster models to demonstrate immunogenicity and protection from virus challenge. Golden Syrian hamsters immunized intramuscularly with two injections of 1 µg or 5 µg of S-2P adjuvanted with CpG 1018 and aluminum hydroxide (alum) were challenged intranasally with SARS-CoV-2. Prior to virus challenge, the vaccine induced high levels of neutralizing antibodies with 10,000-fold higher IgG level and an average of 50-fold higher pseudovirus neutralizing titers in either dose groups than vehicle or adjuvant control groups. Six days after infection, vaccinated hamsters did not display any weight loss associated with infection and had significantly reduced lung pathology and most importantly, lung viral load levels were reduced to lower than detection limit compared to unvaccinated animals. Vaccination with either 1 µg or 5 µg of adjuvanted S-2P produced comparable immunogenicity and protection from infection. This study builds upon our previous results to support the clinical development of MVC-COV1901 as a safe, highly immunogenic, and protective COVID-19 vaccine.

Glucocorticoid induced transcript 1 represses airway remodeling of asthmatic mouse via inhibiting IL-13/periostin/TGF-ß1 signaling.

Asthma is characterized by airway remodeling. Glucocorticoid induced transcript 1 (GLCCI1) was reported to be associated with the development of asthma, while its exact mechanism is still not clear. In our study, ovalbumin (OVA) combined with aluminum hydroxide were used to establish asthmatic mouse model. ELISA assay was fulfilled to ensure the concentration of inflammatory factors in both bronchoalveolar lavage fluid and serum. The pathological changes and collagen deposition in lung tissues were analyzed using H&E staining and Masson staining, respectively. The expression of proteins was measured using western blot, and the expression of GLCCI1 mRNA was ensured by qRT-PCR. Here, we demonstrated that OVA-induced inflammation, lung structural remodeling and collagen deposition in asthmatic mice was notably improved by hydroprednisone treatment or GLCCI1 overexpressing. The expression of GLCCI1 was decreased, while IL-13, periostin and TGF-ß1 were increased in the lung tissue of asthmatic mice. Importantly, upregulation of GLCCI1 suppressed the expression of IL-13, periostin and TGF-ß1, phosphorylation of Smad2 and Smad3, and extracellular matrix (ECM) deposition-related proteins expression. IL-13-induced upregulation of periostin and TGF-ß1 expression, phosphorylation of Smad2 and Smad3, and ECM deposition in airway epithelial cells (AECs) was repressed by GLCCI1 increasing. Furthermore, our results showed that overexpression of GLCCI1 repressed the effect of IL-13 on AECs via inhibiting periostin expression. Overall, our data revealed that GLCCI1 limited the airway remodeling in mice with asthma through inhibiting IL-13/periostin/TGF-ß1 signaling pathway. Our data provided a novel target for asthma treatment.

Pfs230 yields higher malaria transmission-blocking vaccine activity than Pfs25 in humans but not mice.

BACKGROUNDVaccines that block human-to-mosquito Plasmodium transmission are needed for malaria eradication, and clinical trials have targeted zygote antigen Pfs25 for decades. We reported that a Pfs25 protein-protein conjugate vaccine formulated in alum adjuvant induced serum functional activity in both US and Malian adults. However, antibody levels declined rapidly, and transmission-reducing activity required 4 vaccine doses. Functional immunogenicity and durability must be improved before advancing transmission-blocking vaccines further in clinical development. We hypothesized that the prefertilization protein Pfs230 alone or in combination with Pfs25 would improve functional activity.METHODSTransmission-blocking vaccine candidates based on gamete antigen Pfs230 or Pfs25 were conjugated with Exoprotein A, formulated in Alhydrogel, and administered to mice, rhesus macaques, and humans. Antibody levels were measured by ELISA and transmission-reducing activity was assessed by the standard membrane feeding assay.RESULTSPfs25-EPA/Alhydrogel and Pfs230D1-EPA/Alhydrogel induced similar serum functional activity in mice, but Pfs230D1-EPA induced significantly greater activity in rhesus monkeys that was enhanced by complement. In US adults, 2 vaccine doses induced complement-dependent activity in 4 of 5 Pfs230D1-EPA/Alhydrogel recipients but no significant activity in 5 Pfs25-EPA recipients, and combination with Pfs25-EPA did not increase activity over Pfs230D1-EPA alone.CONCLUSIONThe complement-dependent functional immunogenicity of Pfs230D1-EPA represents a significant improvement over Pfs25-EPA in this comparative study. The rhesus model is more predictive of the functional human immune response to Pfs230D1 than is the mouse model.TRIAL REGISTRATIONClinicalTrials.gov NCT02334462.FUNDINGIntramural Research Program of the National Institute of Allergy and Infectious Diseases, National Institutes of Health.

Lack of almagate interference in breath test results for Helicobacter pylori diagnosis (Almatest study). / Ausencia de interferencia de almagato en los resultados de la prueba de aliento para el diagnóstico de Helicobacter pylori (estudio Almatest).

OBJECTIVE: The 13C-urea breath test (UBT) is the most widely used non-invasive diagnostic test for Helicobacter pylori. Debate continues to surround the possible interference of antacid intake on its result. This study aims to confirm the non-interference of almagate in the determination of H. pylori by UBT. PATIENTS AND METHODS: Observational, multicentre study in adult patients treated with almagate in whom a UBT (TAUKIT®) was indicated. When the UBT result was negative, use of almagate was stopped for 30 days and the UBT was repeated. When the result was positive, no further determinations were made. The primary endpoint was the percentage of patients who, having had a negative result in the first breath test, were positive in the second after having stopped taking almagate (UBT false negatives, possibly attributable to almagate). RESULTS: Of the 167 evaluable patients, 59% were female, average age was 49 and 97% had gastrointestinal symptoms. The result of the first UBT was negative in 71% of cases. Of these, in the second UBT test after stopping the almagate, the negative result was confirmed in 97.5%. Out of the total number of cases evaluated, the rate of false negatives was 1.8%. CONCLUSIONS: Taking almagate has minimal or no interference in the result of UBT for the diagnosis of H. pylori infection. It can therefore be used in the weeks prior to a UBT.

A novel STING agonist for cancer immunotherapy and a SARS-CoV-2 vaccine adjuvant.

A novel STING agonist, CDGSF, ipsilaterally modified with phosphorothioate and fluorine, was synthesized. The phosphorothioate in CDGSF might be a site for covalent conjugation. Injection of CDGSF generated an immunogenic ("hot") tumor microenvironment to suppress melanoma, more efficiently than dithio CDG. In particular, immunization with SARS-CoV-2 spike protein using CDGSF as an adjuvant elicited an exceptionally high antibody titer and a robust T cell response, overcoming the drawbacks of aluminum hydroxide. These results highlighted the therapeutic potential of CDGSF for cancer immunotherapy and the adjuvant potential of the STING agonist in the SARS-CoV-2 vaccine for the first time.

Safety and immunogenicity of a synthetic carbohydrate conjugate vaccine against Shigella flexneri 2a in healthy adult volunteers: a phase 1, dose-escalating, single-blind, randomised, placebo-controlled study.

BACKGROUND: Shigella remains in the top four pathogens responsible for moderate to severe diarrhoea in children below 5 years of age. The shigella O-specific polysaccharide (O-SP) is a promising vaccine target. We developed a conjugate vaccine prototype incorporating a unique well defined synthetic oligosaccharide hapten, chemically designed for optimal antigenic, conformational, structural, and functional mimicry of the O-SP from Shigella flexneri 2a (SF2a). We aimed to assess the safety, tolerability, and immunogenicity of this original synthetic oligosaccharide-based vaccine candidate, SF2a-TT15, conceived to drive the antibody response towards the key protective determinants of the native lipopolysaccharide antigen, in a first-in-human phase 1 study. METHODS: We did a first-in-human, dose-escalating, single-blind, observer-masked, randomised, placebo-controlled study at the Clinical Research Center of Tel Aviv Sourasky Medical Center (Israel). Participants were healthy adults aged 18-45 years with low titres of serum SF2a-specific IgG antibodies. 64 eligible participants were assigned to one of two cohorts. 32 participants in each of the two cohorts were randomly assigned via computer-generated algorithm in a stepwise manner to receive the 2 µg (cohort 1) and 10 µg oligosaccharide dose (cohort 2) of the SF2a-TT15 vaccine candidate non-adjuvanted or adjuvanted with aluminium hydroxide (alum) or matching placebos. The vaccine was administered as three single intramuscular injections into the arm, 28 days apart. The primary outcome was the incidence and severity of adverse events, which were assessed in the intention-to-treat safety population analysis including all participants who were randomly assigned and received at least one vaccine or placebo injection. The immunogenicity endpoints were secondary outcomes and were analysed in all participants who were randomly assigned, received all of the assigned injections before the time of the immunogenicity assessment, and provided blood samples for immunological follow-up (per-protocol immunogenicity analysis). The study is registered with ClinicalStudies.gov, NCT02797236 and is completed. FINDINGS: Of 203 volunteers initially screened, 64 participants were enrolled between Sept 20, 2016, and Sept 26, 2017. In each of the two cohorts, 12 participants received the adjuvanted vaccine, 12 received the non-adjuvanted vaccine and eight received the matching placebo (four each). The SF2a-TT15 glycoconjugate was well tolerated at both doses. No serious or severe adverse events occurred. Overall, seven (88%) of eight to 12 (100%) of 12 in each group of volunteers had one adverse event or more after receiving the study agents with the majority of adverse events, 300 (98%) of 307, considered mild in intensity. Of the seven adverse events defined as moderate in severity, one (nausea) was suspected to be related to the vaccine candidate. At all post-immunisation days and for both oligosaccharide doses, whether adjuvanted or not, SF2a-TT15 induced significantly higher serum IgG anti-SF2a lipopolysaccharide geometric mean titres (GMTs) as compared with baseline or with the corresponding GMTs in placebo recipients (p<0·01). After one injection, the non-adjuvanted 10 µg oligosaccharide dose induced a 27-times increase in IgG GMT (5080 vs 189) and the non-adjuvanted 2 µg oligosaccharide dose induced a five-times increase (1411 vs 283), compared with baseline. Alum enhanced the specific IgG response at 2 µg oligosaccharide dose after the third injection (GMTs 3200 vs 1176, p=0.045). INTERPRETATION: SF2a-TT15 was safe and well tolerated and induced high titres of anti-SF2a LPS IgG antibodies. These results support further evaluation of this original synthetic oligosaccharide-protein conjugate vaccine candidate for safety, immunogenicity, and protective efficacy in target populations. FUNDING: The European Union Seventh Framework Programme.

Induction of Airway Hypersensitivity to Ovalbumin and Dust Mite Allergens as Mouse Models of Allergic Asthma.

Mouse models of allergic asthma have been utilized to establish the role of T helper type 2 (Th2) cells in driving lung inflammation, airway hyperresponsiveness, and obstruction. Here, we present the allergic asthma models, in which mice are hypersensitized to ovalbumin (OVA) and house dust mite (HDM). These models mimic the major characteristics of human asthma including the eosinophilic inflammation and hyperactivity of the airway, overproduction of Th2 cytokines in the lung, and elevated total and allergen-specific immunoglobulin E (IgE) in serum.

Experimental Mouse Models of Ragweed- and Papain-Induced Allergic Conjunctivitis.

Mouse models of allergic conjunctivitis mimic various aspects of human allergic conjunctivitis. They are useful as acute models of allergic conjunctivitis to study immunological aspects of this condition. In this chapter, we will describe ragweed-pollen-induced experimental allergic conjunctivitis (mostly driven by adaptive immunity), and papain-soaked contact lens-induced experimental allergic conjunctivitis (mostly driven by innate immunity). Giemsa staining of histological sections is used for quantification of the number of infiltrating eosinophils, which is useful to evaluate the severity of the allergic inflammation. Immunohistochemical staining and quantitative PCR are used to clarify spatiotemporal expression of proinflammatory molecules in the conjunctival tissue. Flow cytometric analysis of conjunctival tissue is used for the detection of innate lymphoid cell type 2 (ILC2) in the ocular surface tissues.

Methods for Experimental Allergen Immunotherapy: Subcutaneous and Sublingual Desensitization in Mouse Models of Allergic Asthma.

Allergic asthma is characterized by airway hyperresponsiveness, remodeling, and reversible airway obstruction. This is associated with an eosinophilic inflammation of the airways, caused by inhaled allergens such as house dust mite or grass pollen. The inhaled allergens trigger a type-2 inflammatory response with the involvement of innate lymphoid cells (ILC2) and Th2 cells, resulting in high immunoglobulin E (IgE) antibody production by B cells and mucus production by airway epithelial cells. As a consequence of the IgE production, subsequent allergen reexposure results in a classic allergic response with distinct early and late phases, both resulting in bronchoconstriction and shortness of breath. Allergen-specific immunotherapy (AIT) is the only treatment that is capable of modifying the immunological process underlying allergic responses including allergic asthma. Both subcutaneous AIT (SCIT) as well as sublingual AIT (SLIT) have shown clinical efficacy in long-term suppression of the allergic response. Although AIT treatments are very successful for rhinitis, application in asthma is hampered by variable efficacy, long duration of treatment, and risk of severe side effects. A more profound understanding of the mechanisms by which AIT induces tolerance to allergens in sensitized individuals is needed to be able to improve its efficacy. Mouse models have been very valuable in preclinical research for characterizing the mechanisms of desensitization in AIT and evaluating novel approaches to improve its efficacy. Here, we present a rapid and reproducible mouse model for allergen-specific immunotherapy. In this model, mice are sensitized with two injections of allergen adsorbed to aluminum hydroxide, followed by subcutaneous injections (SCIT) or sublingual administrations (SLIT) of allergen extracts as an immunotherapy treatment. Finally, mice are challenged by intranasal allergen administrations. We will also describe the protocols as well as the most important readout parameters for the measurements of invasive lung function, serum immunoglobulin levels, isolation of bronchoalveolar lavage fluid (BALF), and preparation of cytospin slides. Moreover, we describe how to perform ex vivo restimulation of lung single-cell suspensions with allergens, flow cytometry for identification of relevant immune cell populations, and ELISAs and Luminex assays for assessment of the cytokine concentrations in BALF and lung tissue.

T-Cell Epitope Immunotherapy in Mouse Models of Food Allergy.

Food allergy has been rising in prevalence over the last two decades, affecting more than 10% of the world population. Current management of IgE-mediated food allergy relies on avoidance and rescue medications; research into treatments that are safer and providing guaranteed and durable curative effects is, therefore, essential. T-cell epitope-based immunotherapy holds the potential for modulating food allergic responses without IgE cross-linking. In this chapter, we describe the methods in evaluating the therapeutic capacities of immunodominant T-cell epitopes in animal models of food allergy. Moreover, we explain in detail the methods to measure the allergen-specific antibody levels, prepare single-cell suspension from spleen, and prepare small intestine for immunohistochemical analysis of eosinophils and Foxp3+ cells.

Glutamic Acid Decarboxylase Injection Into Lymph Nodes: Beta Cell Function and Immune Responses in Recent Onset Type 1 Diabetes Patients.

In spite of intensive treatment Type 1 diabetes leads to serious complications. Preservation of residual beta cell function makes the disease milder, facilitates treatment, prevents complications and increase survival. So far immune interventions have had limited effect, and some serious adverse events and risks. In an open pilot trial we aimed to improve efficacy of GAD-alum treatment using lymph-node administration in combination with oral vitamin D. Here we report the clinical effect and focus on biomarkers for response to treatment. Patients (n = 12) aged 12 to 24 years with recent onset of Type 1 diabetes received 4 µg GAD-alum into lymph-node at day 30, 60, and 90, and oral Vitamin D 2000 U/d, days 1 to 120. Beta cell function was estimated by Mixed Meal Tolerance Tests. GADA, GADA subclasses, GAD65-induced cytokines and proliferation, and T cells markers were analyzed. The treatment was tolerable with no adverse events. Fasting C-peptide and insulin requirement remained stable at 15 months, while HbA1c was lower than baseline. Stimulated C-peptide showed no change at 6 months but declined after 15 months (81% of baseline). Eleven patients remained in partial remission (IDAAC < 9). Patients (n = 9) with better clinical outcome had reduced proportion of IgG1 and increased IgG2, IgG3, and IgG4, increased IL-10 secretion, and reduction of proliferation and CD8+ T cells activation. Patients with poorer clinical response had higher baseline levels of GAD65-induced cytokines and T-cell activation, and an increased ratio of effector/central memory T cells. Intra-lymphatic GAD treatment combined with Vitamin D might preserve beta cell function and improve clinical course in T1D. Patients with less benefit have a different quality of immune response both before and after treatment. Clinical Trial Registration: clinicaltrials.gov, identifier NCT02352974.

CoVaccine HT™ Adjuvant Potentiates Robust Immune Responses to Recombinant SARS-CoV-2 Spike S1 Immunization.

The current COVID-19 pandemic has claimed hundreds of thousands of lives and its causative agent, SARS-CoV-2, has infected millions, globally. The highly contagious nature of this respiratory virus has spurred massive global efforts to develop vaccines at record speeds. In addition to enhanced immunogen delivery, adjuvants may greatly impact protective efficacy of a SARS-CoV-2 vaccine. To investigate adjuvant suitability, we formulated protein subunit vaccines consisting of the recombinant S1 domain of SARS-CoV-2 Spike protein alone or in combination with either CoVaccine HT™ or Alhydrogel. CoVaccine HT™ induced high titres of antigen-binding IgG after a single dose, facilitated affinity maturation and class switching to a greater extent than Alhydrogel and elicited potent cell-mediated immunity as well as virus neutralizing antibody titres. Data presented here suggests that adjuvantation with CoVaccine HT™ can rapidly induce a comprehensive and protective immune response to SARS-CoV-2.

Yeast-expressed SARS-CoV recombinant receptor-binding domain (RBD219-N1) formulated with aluminum hydroxide induces protective immunity and reduces immune enhancement.

We developed a severe acute respiratory syndrome (SARS) subunit recombinant protein vaccine candidate based on a high-yielding, yeast-engineered, receptor-binding domain (RBD219-N1) of the SARS beta-coronavirus (SARS-CoV) spike (S) protein. When formulated with Alhydrogel®, RBD219-N1 induced high levels of neutralizing antibodies against both pseudotyped virus and a clinical (mouse-adapted) isolate of SARS-CoV. Here, we report that mice immunized with RBD219-N1/Alhydrogel® were fully protected from lethal SARS-CoV challenge (0% mortality), compared to ~30% mortality in mice immunized with the SARS S protein formulated with Alhydrogel®, and 100% mortality in negative controls. An RBD219-N1 formulation with Alhydrogel® was also superior to the S protein, unadjuvanted RBD, and AddaVax (MF59-like adjuvant)-formulated RBD in inducing specific antibodies and preventing cellular infiltrates in the lungs upon SARS-CoV challenge. Specifically, a formulation with a 1:25 ratio of RBD219-N1 to Alhydrogel® provided high neutralizing antibody titers, 100% protection with non-detectable viral loads with minimal or no eosinophilic pulmonary infiltrates. As a result, this vaccine formulation is under consideration for further development against SARS-CoV and potentially other emerging and re-emerging beta-CoVs such as SARS-CoV-2.

Whole transcriptome approach to evaluate the effect of aluminium hydroxide in ovine encephalon.

Aluminium hydroxide adjuvants are crucial for livestock and human vaccines. Few studies have analysed their effect on the central nervous system in vivo. In this work, lambs received three different treatments of parallel subcutaneous inoculations during 16 months with aluminium-containing commercial vaccines, an equivalent dose of aluminium hydroxide or mock injections. Brain samples were sequenced by RNA-seq and miRNA-seq for the expression analysis of mRNAs, long non-coding RNAs and microRNAs and three expression comparisons were made. Although few differentially expressed genes were identified, some dysregulated genes by aluminium hydroxide alone were linked to neurological functions, the lncRNA TUNA among them, or were enriched in mitochondrial energy metabolism related functions. In the same way, the miRNA expression was mainly disrupted by the adjuvant alone treatment. Some differentially expressed miRNAs had been previously linked to neurological diseases, oxidative stress and apoptosis. In brief, in this study aluminium hydroxide alone altered the transcriptome of the encephalon to a higher degree than commercial vaccines that present a milder effect. The expression changes in the animals inoculated with aluminium hydroxide suggest mitochondrial disfunction. Further research is needed to elucidate to which extent these changes could have pathological consequences.

Effect of an Inactivated Vaccine Against SARS-CoV-2 on Safety and Immunogenicity Outcomes: Interim Analysis of 2 Randomized Clinical Trials.

Importance: A vaccine against coronavirus disease 2019 (COVID-19) is urgently needed. Objective: To evaluate the safety and immunogenicity of an investigational inactivated whole-virus COVID-19 vaccine in China. Interventions: In the phase 1 trial, 96 participants were assigned to 1 of the 3 dose groups (2.5, 5, and 10 µg/dose) and an aluminum hydroxide (alum) adjuvant-only group (n = 24 in each group), and received 3 intramuscular injections at days 0, 28, and 56. In the phase 2 trial, 224 adults were randomized to 5 µg/dose in 2 schedule groups (injections on days 0 and 14 [n = 84] vs alum only [n = 28], and days 0 and 21 [n = 84] vs alum only [n = 28]). Design, Setting, and Participants: Interim analysis of ongoing randomized, double-blind, placebo-controlled, phase 1 and 2 clinical trials to assess an inactivated COVID-19 vaccine. The trials were conducted in Henan Province, China, among 96 (phase 1) and 224 (phase 2) healthy adults aged between 18 and 59 years. Study enrollment began on April 12, 2020. The interim analysis was conducted on June 16, 2020, and updated on July 27, 2020. Main Outcomes and Measures: The primary safety outcome was the combined adverse reactions 7 days after each injection, and the primary immunogenicity outcome was neutralizing antibody response 14 days after the whole-course vaccination, which was measured by a 50% plaque reduction neutralization test against live severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Results: Among 320 patients who were randomized (mean age, 42.8 years; 200 women [62.5%]), all completed the trial up to 28 days after the whole-course vaccination. The 7-day adverse reactions occurred in 3 (12.5%), 5 (20.8%), 4 (16.7%), and 6 (25.0%) patients in the alum only, low-dose, medium-dose, and high-dose groups, respectively, in the phase 1 trial; and in 5 (6.0%) and 4 (14.3%) patients who received injections on days 0 and 14 for vaccine and alum only, and 16 (19.0%) and 5 (17.9%) patients who received injections on days 0 and 21 for vaccine and alum only, respectively, in the phase 2 trial. The most common adverse reaction was injection site pain, followed by fever, which were mild and self-limiting; no serious adverse reactions were noted. The geometric mean titers of neutralizing antibodies in the low-, medium-, and high-dose groups at day 14 after 3 injections were 316 (95% CI, 218-457), 206 (95% CI, 123-343), and 297 (95% CI, 208-424), respectively, in the phase 1 trial, and were 121 (95% CI, 95-154) and 247 (95% CI, 176-345) at day 14 after 2 injections in participants receiving vaccine on days 0 and 14 and on days 0 and 21, respectively, in the phase 2 trial. There were no detectable antibody responses in all alum-only groups. Conclusions and Relevance: In this interim report of the phase 1 and phase 2 trials of an inactivated COVID-19 vaccine, patients had a low rate of adverse reactions and demonstrated immunogenicity; the study is ongoing. Efficacy and longer-term adverse event assessment will require phase 3 trials. Trial Registration: Chinese Clinical Trial Registry Identifier: ChiCTR2000031809.

Vaccine-Induced Th1-Type Response Protects against Invasive Group A Streptococcus Infection in the Absence of Opsonizing Antibodies.

Recent global advocacy efforts have highlighted the importance of development of a vaccine against group A Streptococcus (GAS). Combo5 is a non-M protein-based vaccine that provides protection against GAS skin infection in mice and reduces the severity of pharyngitis in nonhuman primates. However, Combo5 with the addition of aluminum hydroxide (alum) as an adjuvant failed to protect against invasive GAS infection of mice. Here, we show that formulation of Combo5 with adjuvants containing saponin QS21 significantly improves protective efficacy, even though all 7 adjuvants tested generated high antigen-specific IgG antibody titers, including alum. Detailed characterization of Combo5 formulated with SMQ adjuvant, a squalene-in-water emulsion containing a TLR4 agonist and QS21, showed significant differences from the results obtained with alum in IgG subclasses generated following immunization, with an absence of GAS opsonizing antibodies. SMQ, but not alum, generated strong interleukin-6 (IL-6), gamma interferon (IFN-γ), and tumor necrosis alpha (TNF-α) responses. This work highlights the importance of adjuvant selection for non-M protein-based GAS vaccines to optimize immune responses and protective efficacy.IMPORTANCE Availability of a group A Streptococcus vaccine remains an unmet public health need. Here, we tested different adjuvant formulations to improve the protective efficacy of non-M protein vaccine Combo5 in an invasive disease model. We show that novel adjuvants can dramatically shape the type of immune response developed following immunization with Combo5 and significantly improve protection. In addition, protection afforded by Combo5 is not mediated by opsonizing antibodies, believed to be the main correlate of protection against GAS infections. Overall, this report highlights the importance of adjuvant selection in raising protective immune responses against GAS invasive infection. Adjuvants that can provide a more balanced Th1/Th2-type response may be required to optimize protection of GAS vaccines, particularly those based on non-M protein antigens.

Detection of aluminum in lumbar spinal cord of sheep subcutaneously inoculated with aluminum-hydroxide containing products.

The use of vaccines containing aluminum (Al) adjuvants is widespread in ovine production. Al adjuvants induce an effective immune-response but lead to the formation of post-vaccination granulomas from which Al can disseminate. This work aims to study the accumulation of Al in the central nervous system of sheep subcutaneously inoculated with Al-hydroxide containing products. Lumbar spinal cord and parietal lobe from 21 animals inoculated with 19 doses of Vaccine (n = 7), Adjuvant-only (n = 7) or phosphate-buffered saline as Control (n = 7) were analyzed with transversely heated graphite furnace atomic absorption spectroscopy and lumogallion staining for Al analytical measurements and Al tisular localization respectively. In the lumbar spinal cord, Al median content was higher in both the Adjuvant-only and Vaccine group (p = .001) compared with the Control group. Animals of the Adjuvant-only group showed the higher individual measurements in the lumbar spinal cord (14.36 µg/g and 7.83 µg/g). In the parietal lobe, Al median content tended to be higher in the Adjuvant-only group compared with Control group (p = .074). Except for three replicates of the Adjuvant-only group, Al content was always below 1 µg/g. In the lumbar spinal cord, lumogallion-reactive Al deposits were more abundant in the gray matter than in the white matter in both Vaccine (p = .034) and Adjuvant-only groups (p = .017) and Al deposits were mostly associated with glial-like cells (p = .042). In the parietal lobe, few Al deposits, which were sometimes related to blood vessels, were found. In sheep, Al-hydroxide adjuvants inoculated in the subcutaneous tissue selectively accumulate in the lumbar spinal cord.