Recombinant Protein Subunit Vaccines Research Articles

Combination application of Pickering emulsion and BLS protein nanoparticles enhances vaccine efficacy.

The deficiency of recombinant protein immune response could be compensated for by using nanoparticle platforms or adding immune enhancers, however existing vaccines or adjuvants struggle to elicit durable cellular immune responses. In this work, a protein nanoscaffold, lumazine synthase isolated from Brucella (BLS) was optimally designed that could facilitate cellular uptake of displayed antigens and the maturation of bone marrow-derived dendritic cells (BMDCs), and enhancing humoral immune responses. To enhance cellular immune response, chitosan hydrochloride-stabilized Pickering emulsion (CHSPE) was evaluated as an adjuvant for the BLS nanoscaffold-based vaccine. CHSPE could enhance the recruitment and activation of DCs at the injection site and the uptake of antigen and activation of DCs in the draining lymph nodes (dLNs), compared with commercial adjuvant ISA 206. In addition, CHSPE induced antigen-specific antibody levels comparable to those of ISA 206 and increased the ratio of central memory T cells (TCM) and effector memory T cells (TEM), and promoted the secretion of Th1-type cytokines. Moreover, CHSPE-formulated vaccine provided a similar level of protection to the live attenuated vaccine and was superior to that of ISA 206. Taken together, the combination of the BLS nanoscaffold and CHSPE provides a feasible strategy for recombinant protein subunit vaccine development.

Immunogenicity and safety of SARS-CoV-2 recombinant protein subunit vaccine (IndoVac) adjuvanted with alum and CpG 1018 in Indonesian adults: A phase 3, randomized, active-controlled, multicenter trial

BackgroundBio Farma has developed a recombinant protein subunit vaccine (IndoVac) that is indicated for active immunization in population of all ages. This article reported the results of the phase 3 immunogenicity and safety study in Indonesian adults aged 18 years and above. MethodsWe conducted a randomized, active-controlled, multicenter, prospective intervention study to evaluate the immunogenicity and safety of IndoVac in adults aged 18 years and above. Participants who were SARS-CoV-2 vaccine-naïve received two doses of either IndoVac or control (Covovax) with 28 days interval between doses and were followed up until 12 months after complete vaccination. ResultsA total of 4050 participants were enrolled from June to August 2022 and received at least one dose of vaccine. The geometric mean ratio (GMR) of neutralizing antibody at 14 days after the second dose was 1.01 (95 % confidence interval (CI) 0.89–1.16), which met the WHO non-inferiority criteria for immunobridging (95 % CI lower bound > 0.67). The antibody levels were maintained through 12 months after the second dose. The incidence rate of adverse events (AEs) were 27.95 % in IndoVac group and 32.15 % in Covovax group with mostly mild intensity (27.70 %). The most reported solicited AEs were pain (14.69 %) followed by myalgia (7.48 %) and fatigue (6.77 %). Unsolicited AEs varied, with each of the incidence rate under 5 %. There were no serious AEs assessed as possibly, probably, or likely related to vaccine. ConclusionsIndoVac in adults showed favourable safety profile and elicited non-inferior immune response to Covovax. (ClinicalTrials.gov: NCT05433285, Indonesian Clinical Research Registry: INA-R5752S9).

Retraction: "Safety and immunogenicity of a recombinant receptor-binding domain-based protein subunit vaccine (Noora vaccine™) against COVID-19 in adults: A randomized, double-blind, placebo-controlled, Phase 1 trial".

Retraction: "Safety and immunogenicity of a recombinant receptor-binding domain-based protein subunit vaccine (Noora vaccine™) against COVID-19 in adults: A randomized, double-blind, placebo-controlled, Phase 1 trial," by Salimian J, Ahmadi A, Amani J, et al. J Med Virol. 2022;95:e28097. The above article, published online on August 27, 2022 in Wiley Online Library (https://onlinelibrary.wiley.com/doi/10.1002/jmv.28097) has been retracted by agreement between the journal's Editor in Chief, Shou-Jiang (SJ) Gao, and Wiley Periodicals LLC. The retraction has been agreed due to concerns raised by third parties regarding issues with the data presented in the article.1 Several inconsistencies concerning the information provided about the analyzed subjects were additionally identified. Furthermore, the authors failed to disclose the presence of potential conflicts of interest that may have affected the interpretation of the results presented. Accordingly, the editors consider the conclusions of this manuscript to be invalid. The authors have been informed of the decision to retract but did not agree with it. REFERENCE 1. Forthal DN. Comment on the immunogenicity of the Noora vaccine against SARS-CoV-2. J Med Virol. 2023;95:e28731. doi:10.1002/jmv.28731.

COVID-19 vaccination of patients with chronic immune-mediated inflammatory disease

ObjectiveThis study aimed to analyze the safety and efficacy of COVID-19 vaccines among patients with chronic immune-mediated inflammatory disease (IMID) in China.MethodsParticipants who were diagnosed with a chronic IMID were eligible for inclusion in this study. Age- and sex-matched healthy vaccinated individuals were set as the control group. All participants received two doses of the inactivated CoronaVac vaccine or three doses of the recombinant protein subunit vaccine ZF2001. Adverse events, IMID activity after vaccination, and the rate of COVID-19 in the two groups were compared.ResultsThere were 158 patients in the IMID group, with an average age of 40 ± 14 years old, and 98 female subjects. In the IMID group, 123 patients received the inactivated CoronaVac vaccine, and 35 patients received the recombinant protein subunit vaccine ZF2001. There were 153 individuals in the control group, including 122 who received the CoronaVac vaccine and 31 who received the recombinant protein subunit vaccine ZF2001. The frequency of vaccine-related adverse events in the IMID group was less than that in the control group, all of which were mild local effects, and no serious events occurred. Of note, no disease flares occurred in the IMID group. No participants in either group subsequently got COVID-19, so the incidence rate was 0% in both groups.ConclusionCOVID-19 vaccination was found to be safe for IMID subjects, any adverse events were mild, and vaccination did not increase the risk of disease activity. Meanwhile, vaccination could effectively reduce the incidence of COVID-19 in IMID patients. In the future, studies with a larger sample size and a longer duration are needed.

Boosting with an aerosolized Ad5-nCoV elicited robust immune responses in inactivated COVID-19 vaccines recipients.

The SARS-CoV-2 Omicron variant has become the dominant SARS-CoV-2 variant and exhibits immune escape to current COVID-19 vaccines, the further boosting strategies are required. We have conducted a non-randomized, open-label and parallel-controlled phase 4 trial to evaluate the magnitude and longevity of immune responses to booster vaccination with intramuscular adenovirus vectored vaccine (Ad5-nCoV), aerosolized Ad5-nCoV, a recombinant protein subunit vaccine (ZF2001) or homologous inactivated vaccine (CoronaVac) in those who received two doses of inactivated COVID-19 vaccines. The aerosolized Ad5-nCoV induced the most robust and long-lasting neutralizing activity against Omicron variant and IFNg T-cell response among all the boosters, with a distinct mucosal immune response. SARS-CoV-2-specific mucosal IgA response was substantially generated in subjects boosted with the aerosolized Ad5-nCoV at day 14 post-vaccination. At month 6, participants boosted with the aerosolized Ad5-nCoV had remarkably higher median titer and seroconversion of the Omicron BA.4/5-specific neutralizing antibody than those who received other boosters. Our findings suggest that aerosolized Ad5-nCoV may provide an efficient alternative in response to the spread of the Omicron BA.4/5 variant. https://www.chictr.org.cn/showproj.html?proj=152729, identifier ChiCTR2200057278.

Live attenuated vaccines and layered defense strategies to combat infections caused by nonencapsulated Yersinia pestis

IntroductionPlague is an ancient disease caused by Yersinia pestis, a widely disseminated Tier 1 pathogen that poses significant public health and biothreat risks. The rapid course and high mortality of pneumonic plague limit the efficacy of antibiotic treatment and mandate the need for an effective, licensed, and readily available vaccine. New candidate vaccines are being developed; however, their efficacy in nonhuman primates, optimal vaccination schedule and immune response, duration of protection, and breadth of coverage against various virulent strains are inadequately understood. In the current work, we explored homologous and heterologous vaccination schemes using the sensitive BALB/c mouse models of bubonic and pneumonic plague challenged with Y. pestis strain C12. This strain, a derivative of the wild-type strain CO92, lacks the anti-phagocytic F1 capsule yet remains highly virulent. Protection against such nonencapsulated strains has been particularly elusive.MethodsWe tested the efficacy of live attenuated vaccine (LAV) derivatives of Y. pestis CO92 or C12 with a deletion of a type 3 secretion-associated gene (ΔyscN) or the pgm pigmentation locus, and they were cured of the pPst (PCP1) plasmid (CO92 pgm− pPst−). The LAVs were evaluated alone or accompanied by a dose of a protein subunit vaccine (rF1V or rV).ResultsThe most protective and immunogenic vaccination scheme, as tested under a variety of conditions in bubonic and pneumonic plague models, was heterologous vaccination with a LAV and the recombinant rF1V or rV protein subunit vaccine. Furthermore, in the heterologous scheme, different LAVs and subunit vaccines could be substituted, affording flexibility in vaccine component selection. We also evaluated a novel intervention strategy consisting of vaccination and post-exposure antibiotic treatment. The layering of vaccination with the LAVs and post-exposure treatment with streptomycin was synergistic, extending the time after the Y. pestis C12 challenge when treatment remained effective and affording a sparing of antibiotics.ConclusionThe current work defined effective and flexible vaccination and treatment interventions that successfully prevented lethal infection with virulent, nonencapsulated Y. pestis.

Vaccination against coronavirus disease 2019 in patients with pulmonary hypertension: A national prospective cohort study.

Coronavirus disease 2019 (COVID-19) has potential risks for both clinically worsening pulmonary hypertension (PH) and increasing mortality. However, the data regarding the protective role of vaccination in this population are still lacking. This study aimed to assess the safety of approved vaccination for patients with PH. In this national prospective cohort study, patients diagnosed with PH (World Health Organization [WHO] groups 1 and 4) were enrolled from October 2021 to April 2022. The primary outcome was the composite of PH-related major adverse events. We used an inverse probability weighting (IPW) approach to control for possible confounding factors in the baseline characteristics of patients. In total, 706 patients with PH participated in this study (mean age, 40.3 years; mean duration after diagnosis of PH, 8.2 years). All patients received standardized treatment for PH in accordance with guidelines for the diagnosis and treatment of PH in China. Among them, 278 patients did not receive vaccination, whereas 428 patients completed the vaccination series. None of the participants were infected with COVID-19 during our study period. Overall, 398 patients received inactivated severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine, whereas 30 received recombinant protein subunit vaccine. After adjusting for baseline covariates using the IPW approach, the odds of any adverse events due to PH in the vaccinated group did not statistically significantly increase (27/428 [6.3%] vs. 24/278 [8.6%], odds ratio = 0.72, P = 0.302). Approximately half of the vaccinated patients reported at least one post-vaccination side effects, most of which were mild, including pain at the injection site (159/428, 37.1%), fever (11/428, 2.6%), and fatigue (26/428, 6.1%). COVID-19 vaccination did not significantly augment the PH-related major adverse events for patients with WHO groups 1 and 4 PH, although there were some tolerable side effects. A large-scale randomized controlled trial is warranted to confirm this finding. The final approval of the COVID-19 vaccination for patients with PH as a public health strategy is promising.

A Brighton Collaboration standardized template with key considerations for a benefit/risk assessment for the Medigen COVID-19 protein vaccine

The Brighton Collaboration Benefit-Risk Assessment of VAccines by TechnolOgy (BRAVATO) Working Group has prepared standardized templates to describe the key considerations for the benefit-risk assessment of several vaccine platform technologies, including protein subunit vaccines. This article uses the BRAVATO template to review the features of the MVC-COV1901 vaccine, a recombinant protein subunit vaccine based on the stabilized pre-fusion SARS-CoV-2 spike protein S-2P, adjuvanted with CpG 1018 and aluminum hydroxide, manufactured by Medigen Vaccine Biologics Corporation in Taiwan. MVC-COV1901 vaccine is indicated for active immunization to prevent COVID-19 caused by SARS-CoV-2 in individuals 12 years of age and older. The template offers details on basic vaccine information, target pathogen and population, characteristics of antigen and adjuvant, preclinical data, human safety and efficacy data, and overall benefit-risk assessment.The clinical development program began in September 2020 and based on demonstration of favorable safety and immunogenicity profiles in 11 clinical trials in over 5,000 participants, it has been approved for emergency use based on immunobridging results for adults in Taiwan, Estwatini, Somaliland, and Paraguay. The main clinical trials include placebo-controlled phase 2 studies in healthy adults (CT-COV-21), adolescents (CT-COV-22), and elderly population (CT-COV-23) as well as 3 immunobridging phase 3 trials (CT-COV-31, CT-COV-32, and CT-COV-34) in which MVC-COV1901 was compared to AZD1222. There are also clinical trials studying MVC-COV1901 as homologous and heterologous boosters (CT-COV-24 and CT-COV-25).The totality of evidence based on ∼3 million vaccinees to date includes a mostly clean safety profile, with adverse events mostly being mild and self-limiting in both clinical development and post-marketing experience, proven immunogenic response, and real-world effectiveness data. The immunogenic profile demonstrates that MVC-COV1901 induces high levels of neutralizing and binding antibodies against SARS-CoV-2. There is a dose-dependent response and a significant correlation between binding and neutralizing antibody activity. Antigen-specific T-cell responses, particularly a Th1-biased immune response characterized by high levels of interferon gamma and IL-2 cytokines, have also been observed. Coupled with this, MVC-COV1901 has favorable thermostability and better safety profiles when compared to other authorized vaccines from different platforms, which make it potentially a good candidate for vaccine supply chains in global markets.

Safety and immunogenicity of a protein subunit COVID-19 vaccine (ZF2001) in healthy children and adolescents aged 3–17 years in China: a randomised, double-blind, placebo-controlled, phase 1 trial and an open-label, non-randomised, non-inferiority, phase 2 trial

Safety and immunogenicity of a protein subunit COVID-19 vaccine (ZF2001) in healthy children and adolescents aged 3–17 years in China: a randomised, double-blind, placebo-controlled, phase 1 trial and an open-label, non-randomised, non-inferiority, phase 2 trial

The Efficacy and Safety of SARS-CoV-2 Vaccinations in People with Multiple Sclerosis

While people with multiple sclerosis (MS) are not more likely to contract COVID-19, the incidences of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and COVID-19-related complications may be higher for people with MS who have comorbidities or who are taking certain disease modifying therapies (DMT). Robert Shin, Professor of Neurology at MedStar Georgetown University Hospital, Washington, D.C., USA, and Deborah Fuller, Department of Microbiology, University of Washington School of Medicine, and Associate Director of the Washington National Primate Research Center, Seattle, Washington, USA, first discussed why vaccinations against SARS-CoV-2 should be recommended to people with MS. They then discussed evidence that suggests that the antibody response following vaccination may be dampened in people taking some DMTs, especially those that deplete CD20+ B cells; however, T cell responses to vaccinations may also provide protection. There is also evidence that messenger RNA (mRNA) SARS-CoV-2 vaccines, as opposed to viral vector or recombinant protein subunit vaccines, and boosters may lead to a better antibody response. Vaccine responses vary between patients taking different sphinogosine-1-phosphate (S1P) receptor modulators, being low for fingolimod and high for next generation S1P receptor modulators. Overall, more studies of vaccine response and timing are needed to best update the guidelines for people with MS.

Antibodies Induced by Homologous or Heterologous Inactivated (CoronaVac/BBIBP-CorV) and Recombinant Protein Subunit Vaccines (ZF2001) Dramatically Enhanced Inhibitory Abilities against B.1.351, B.1.617.2, and B.1.1.529 Variants.

Safe and effective vaccines for Corona Virus Disease 2019 (COVID-19) can prevent the virus from infecting human populations and treat patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In this study, we discuss the inhibitory abilities of primary and booster vaccine-induced antibodies inhibitory ability toward the SARS-CoV-2 wild-type strain, as well as B.1.1.7, B.1.351, P.1, B.1.617.2, and B.1.1.529. We confirmed these antibodies had the strongest inhibitory effects on the wild-type strain and cross-inhibition activities against other mutant strains after two inactivated vaccine doses. However, the B.1.351, B.1.617.2 and B.1.1.529 mutants exhibit antibody resistance in the vaccine serum. Antibodies induced by homologous inactivated vaccines (n = 92) presented more effective inhibition against tested SARS-CoV-2 strains (p < 0.0001), especially B.1.351, B.1.617.2, and B.1.1.529 mutant strains, which had strong immune escape characteristics. In addition, a heterologous booster vaccination (n = 50) of a protein subunit vaccine ZifiVax (ZF2001) significantly restored humoral immune responses and even showed an increasing response against wild-type, B.1.351, B.1.617.2, and B.1.1.529 than homologous inactivated vaccines. Our analysis of the humoral immune response elicited by the different vaccine regimens, including inhibiting antibodies, indicated that a booster, whether homologous or heterologous, could be essential for achieving greater efficacy against SARS-CoV-2.

A therapeutic vaccine strategy to prevent Pneumocystis pneumonia in an immunocompromised host in a non-human primate model of HIV and Pneumocystis co-infection.

Pneumocystis is a ubiquitous fungal pathogen that causes pneumonia (PCP) and pulmonary sequelae in HIV-infected individuals and other immunocompromised populations. With the success of anti-retroviral therapy for HIV-infected individuals the frequency of PCP in that population has decreased, however, PCP remains a significant cause of morbidity and mortality in individuals with hematologic and solid malignancies, and in individuals treated with immunosuppressive therapies for autoimmune diseases, and following bone marrow and solid organ transplantation. Despite the clinical need, there is no approved vaccine to prevent PCP in vulnerable populations. The ultimate goal of the field is to develop an effective vaccine that can overcome immune deficits in at risk populations and induce long-lasting protective immunity to Pneumocystis. Toward this goal, our laboratory has established a model of PCP co-infection in simian immunodeficiency virus (SIV)-infected non-human primates (NHP) and identified a recombinant protein sub-unit vaccine, KEX1, that induces robust anti-Pneumocystis immunity in immune-competent macaques that is durable and prevents PCP following simian immunodeficiency virus (SIV)-induced immunosuppression. Type I, or invariant natural killer T (iNKT) cells have the potential to provide B cell help under conditions of reduced CD4+ T cell help. In the present study, we used the SIV model of HIV infection to address whether therapeutic vaccination with the iNKT cell-activating adjuvant α-galactosylceramide (α-GC) and KEX1 (α-GC+KEX1) can effectively boost anti-Pneumocystis humoral immunity following virus-induced immunosuppression. Immunization of antigen-experienced NHPs with α-GC+KEX1 during the early chronic phase of SIV-infection significantly boosted anti-Pneumocystis humoral immunity by increasing memory B cells and antibody titers, and enhanced titer durability during SIV-induced immunosuppression. This therapeutic vaccination strategy boosted anti-Pneumocystis immune responses during SIV-infection and contributed to protection against Pneumocystis co-infection in KEX1-vaccinated macaques. These studies present a novel strategy for stimulating durable anti-Pneumocystis humoral immunity in the context of complex, chronic SIV-induced immunosuppression and may be further applied to immunization of other immunosuppressed populations, and toward other common recall antigens.

Mixed formulation of mRNA and protein-based COVID-19 vaccines triggered superior neutralizing antibody responses.

Integrating different types of vaccines into a singular immunization regimen is an effective and accessible approach to strengthen and broaden the immunogenicity of existing coronavirus disease 2019 (COVID-19) vaccine candidates. To optimize the immunization strategy of the novel mRNA-based vaccine and recombinant protein subunit vaccine that attracted much attention in COVID-19 vaccine development, we evaluated the immunogenicity of different combined regimens with the mRNA vaccine (RNA-RBD) and protein subunit vaccine (PS-RBD) in mice. Compared with homologous immunization of RNA-RBD or PS-RBD, heterologous prime-boost strategies for mRNA and protein subunit vaccines failed to simultaneously enhance neutralizing antibody (NAb) and Th1 cellular response in this study, showing modestly higher serum neutralizing activity and antibody-dependent cell-mediated cytotoxicity for "PS-RBD prime, RNA-RBD boost" and robust Th1 type cellular response for "RNA-RBD prime, PS-RBD boost". Interestingly, immunizing the mice with the mixed formulation of the two aforementioned vaccines in various proportions further significantly enhanced the NAb responses against ancestral, Delta, and Omicron strains and manifested increased Th1-type responses, suggesting that a mixed formulation of mRNA and protein vaccines might be a more prospective vaccination strategy. This study provides basic research data on the combined vaccination strategies of mRNA and protein-based COVID-19 vaccines.

Using Dual Toll-like Receptor Agonism to Drive Th1-Biased Response in a Squalene- and α-Tocopherol-Containing Emulsion for a More Effective SARS-CoV-2 Vaccine.

A diversity of vaccines is necessary to reduce the mortality and morbidity of SARS-CoV-2. Vaccines must be efficacious, easy to manufacture, and stable within the existing cold chain to improve their availability around the world. Recombinant protein subunit vaccines adjuvanted with squalene-based emulsions such as AS03™ and MF59™ have a long and robust history of safe, efficacious use with straightforward production and distribution. Here, subunit vaccines were made with squalene-based emulsions containing novel, synthetic toll-like receptor (TLR) agonists, INI-2002 (TLR4 agonist) and INI-4001 (TLR7/8 agonist), using the recombinant receptor-binding domain (RBD) of SARS-CoV-2 S protein as an antigen. The addition of the TLR4 and TLR7/8 agonists, alone or in combination, maintained the formulation characteristics of squalene-based emulsions, including a sterile filterable droplet size (<220 nm), high homogeneity, and colloidal stability after months of storage at 4, 25, and 40 °C. Furthermore, the addition of the TLR agonists skewed the immune response from Th2 towards Th1 in immunized C57BL/6 mice, resulting in an increased production of IgG2c antibodies and a lower antigen-specific production of IL-5 with a higher production of IFNγ by lymphocytes. As such, incorporating TLR4 and TLR7/8 agonists into emulsions leveraged the desirable formulation and stability characteristics of emulsions and can induce Th1-type humoral and cell-mediated immune responses to combat the continued threat of SARS-CoV-2.

SARS-CoV-2 Vaccines: The Mucosal Immunity Imperative

SARS-CoV-2 Vaccines: The Mucosal Immunity Imperative

Contemporary COVID-19 Vaccines: The Science and Marketing

Published on:June 2022Journal of Young Pharmacists, 2022; 14(2):133-139Review Article | doi:10.5530/jyp.2022.14.27 Authors: Sunil Chiplunkar1, Atul Baravkar2,*, Sukanya Paricharak2, Apeksha Masal2, Nitin Aher3 1Business Development, Group Pharmaceuticals, Bangalore, Karnataka, INDIA.2Development of Agricultural, Trust’s Shardabai Pawar Institute of Pharmaceutical Sciences and Research, Baramati, Maharashtra, INDIA.3Ashwin College of Pharmacy, Sangamner, Maharashtra, INDIA. Abstract: Objectives: The viral infection pandemic caused by SARS-CoV-2 has resulted in a flurry of research in the field of immunologicals. Scientific terms like antigen, antibody and immunoglobulins have entered the lexicon of citizens. Ending the pandemic through measures such as double masking, physical distancing and lockdowns have been imposed to break the chain of COVID-19 infection transmission, however, once again it is the vaccines that have proved worthy to improve immunity and halt the march of COVID-19. Methods: The vaccination process at optimal levels is aimed at desired antibodies. The impetus provided to vaccine technology commercialization is immense. mRNA vaccines have stolen the march, however, the traditional whole virion inactivated vaccine has made a comeback, new plasmid DNA technology vaccine has made a breakthrough, nasal vaccines are being designed, and recombinant protein subunit vaccine has given new affordability; oral vaccines are in the pipeline. Conclusion: Scientists and technologists have proved their worth through innovative vaccine work. This article reviews the science and marketing of COVID-19 vaccines.Key words: COVID-19, Digital marketing, SARS-CoV-2, Pandemic, Pharmaceutical marketing.

Immunogenicity and protective efficacy of a recombinant protein subunit vaccine and an inactivated vaccine against SARS-CoV-2 variants in non-human primates

Emerging SARS-CoV-2 variants and the gradually decreasing neutralizing antibodies over time post vaccination have led to an increase in incidents of breakthrough infection across the world. To investigate the potential protective effect of the recombinant protein subunit COVID-19 vaccine targeting receptor-binding domain (RBD) (PS-RBD) and whole inactivated virus particle vaccine (IV) against the variant strains, in this study, rhesus macaques were immunized with PS-RBD or IV vaccine, followed by a Beta variant (B.1.351) challenge. Although neutralizing activity against the Beta variant was reduced compared with that against the prototype, the decreased viral load in both upper and lower respiratory tracts, milder pathological changes, and downregulated inflammatory cytokine levels in lung tissues after challenge demonstrated that PS-RBD and IV still provided effective protection against the Beta variant in the macaque model. Furthermore, PS-RBD-induced macaque sera possessed general binding and neutralizing activity to Alpha, Beta, Delta, and Omicron variants in our study, though the neutralizing antibody (NAb) titers declined by varying degrees, demonstrating potential protection of PS-RBD against current circulating variants of concern (VOCs). Interestingly, although the IV vaccine-induced extremely low neutralizing antibody titers against the Beta variant, it still showed reduction for viral load and significantly alleviated pathological change. Other correlates of vaccine-induced protection (CoP) like antibody-dependent cellular cytotoxicity (ADCC) and immune memory were both confirmed to be existing in IV vaccinated group and possibly be involved in the protective mechanism.

Safety of SARS-CoV-2 vaccines in patients with chronic myeloid leukemia: a multicenter survey in China.

Safety of SARS-CoV-2 vaccines in patients with chronic myeloid leukemia: a multicenter survey in China.

The Recent Developmental Platforms and Potential Targets of SARS CoV-2 Vaccines: A Comprehensive Review

The novel coronavirus disease is a rapidly spreading infection caused by recently discovered different variants of SARS CoV-2 viruses, causing mild to severe respiratory symptoms in the majority of people. The Coronavirus disease 2019 pandemic has spread almost all the nooks and corners of the world. There are significant possible approaches pharmaceutically to fight against COVID-19. Original full-text research articles were searched online in PubMed, ScienceDirect, ResearchGate, Google Scholar, Core and Wiley Online Library. Scientists throughout the world are working on different platforms and targeting certain proteins moieties against SARS CoV-2 for the development of methods of safety, efficacy and potential vaccine candidates. Many candidates showed efficacy in In-vitro studies but relatively few clinical studies proceeded through different vaccine development platforms, such as entire virus vaccines, plant-based and nucleic acid vaccines, recombinant protein subunit vaccines. This review study provides a short description of SARS-CoV-2 characteristics and deals with recent developments in the design of attempts to produce vaccines to combat COVID-19.

A recombinant spike protein subunit vaccine confers protective immunity against SARS-CoV-2 infection and transmission in hamsters.

Multiple safe and effective vaccines that elicit immune responses against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are necessary to respond to the ongoing coronavirus disease 2019 (COVID-19) pandemic. Here, we developed a protein subunit vaccine composed of spike ectodomain protein (StriFK) plus a nitrogen bisphosphonate-modified zinc-aluminum hybrid adjuvant (FH002C). StriFK-FH002C generated substantially higher neutralizing antibody titers in mice, hamsters, and cynomolgus monkeys than those observed in plasma isolated from COVID-19 convalescent individuals. StriFK-FH002C also induced both TH1- and TH2-polarized helper T cell responses in mice. In hamsters, StriFK-FH002C immunization protected animals against SARS-CoV-2 challenge, as shown by the absence of virus-induced weight loss, fewer symptoms of disease, and reduced lung pathology. Vaccination of hamsters with StriFK-FH002C also reduced within-cage virus transmission to unvaccinated, cohoused hamsters. In summary, StriFK-FH002C represents an effective, protein subunit-based SARS-CoV-2 vaccine candidate.