Evaluation of Binding and Neutralizing Antibodies for Inactivated SARS-CoV-2 Vaccine Immunization

The circulating severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) variant presents an ongoing challenge for surveillance and detection. It is important to establish an assay for SARS-CoV-2 antibodies in vaccinated individuals. Numerous studies have demonstrated that binding antibodies (such as S-IgG and N-IgG) and neutralizing antibodies (Nabs) can be detected in vaccinated individuals. However, it is still unclear how to evaluate the consistency and correlation between binding antibodies and Nabs induced by inactivated SARS-CoV-2 vaccines. In this study, serum samples from humans, rhesus macaques, and hamsters immunized with inactivated SARS-CoV-2 vaccines were analyzed for S-IgG, N-IgG, and Nabs. The results showed that the titer and seroconversion rate of S-IgG were significantly higher than those of N-IgG. The correlation between S-IgG and Nabs was higher compared to that of N-IgG. Based on this analysis, we further investigated the titer thresholds of S-IgG and N-IgG in predicting the seroconversion of Nabs. According to the threshold, we can quickly determine the positive and negative effects of the SARS-CoV-2 variant neutralizing antibody in individuals. These findings suggest that the S-IgG antibody is a better supplement to and confirmation of SARS-CoV-2 vaccine immunization.

Heterologous Booster Immunization Based on Inactivated SARS-CoV-2 Vaccine Enhances Humoral Immunity and Promotes BCR Repertoire Development

Recent studies have indicated that sequentially administering SARS-CoV-2 vaccines can result in increased antibody and cellular immune responses. In this study, we compared homologous and heterologous immunization strategies following two doses of inactivated vaccines in a mouse model. Our research demonstrates that heterologous sequential immunization resulted in more immune responses displayed in the lymph node germinal center, which induced a greater number of antibody-secreting cells (ASCs), resulting in enhanced humoral and cellular immune responses and increased cross-protection against five variant strains. In further single B-cell analysis, the above findings were supported by the presence of unique B-cell receptor (BCR) repertoires and diversity in CDR3 sequence profiles elicited by a heterologous booster immunization strategy.

Preclinical safety evaluation of a bivalent inactivated EV71-CA16 vaccine in mice immunized intradermally

Hand, foot and mouth disease is a common acute viral infectious disease that poses a serious threat to the life and health of young children. With the development of an effective inactivated EV71 vaccine, CA16 has become the main pathogen causing HFMD. Effective and safe vaccines against this disease are urgently needed. In our previous study, a bivalent inactivated vaccine was shown to have good immunogenicity and to induce neutralizing antibodies in mice and monkeys. Repeated administration toxicity is a critical safety test in the preclinical evaluation of vaccines. In this study, BALB/c mice were used to evaluate the toxicity of the bivalent vaccine after multiple intradermal administrations. Clinical observation was performed daily, and body weight, food intake, hematological characteristics, serum biochemical parameters, antinuclear antibodies, CD4⁺/CD8a⁺ T-cell proportions, bone marrow smear results and pathology results were recorded. The results showed that there was no significant change at the injection site and no adverse reactions related to the vaccine. The bivalent inactivated EV71-CA16 vaccine exhibits good safety in mice, and these results provide a sufficient basis for further clinical trials.

Long-Term Cross Immune Response in Mice following Heterologous Prime-Boost COVID-19 Vaccination with Full-Length Spike mRNA and Recombinant S1 Protein

(1) Background: As the COVID-19 pandemic enters its fourth year, it continues to cause significant morbidity and mortality worldwide. Although various vaccines have been approved and the use of homologous or heterologous boost doses is widely promoted, the impact of vaccine antigen basis, forms, dosages, and administration routes on the duration and spectrum of vaccine-induced immunity against variants remains incompletely understood. (2) Methods: In this study, we investigated the effects of combining a full-length spike mRNA vaccine with a recombinant S1 protein vaccine, using intradermal/intramuscular, homologous/heterologous, and high/low dosage immunization strategies. (3) Results: Over a period of seven months, vaccination with a mutant recombinant S1 protein vaccine based on the full-length spike mRNA vaccine maintained a broadly stable humoral immunity against the wild-type strain, a partially attenuated but broader-spectrum immunity against variant strains, and a comparable level of cellular immunity across all tested strains. Furthermore, intradermal vaccination enhanced the heterologous boosting of the protein vaccine based on the mRNA vaccine. (4) Conclusions: This study provides valuable insights into optimizing vaccination strategies to address the ongoing challenges posed by emerging SARS-CoV-2 variants.

Evaluation of Immunogenicity and Clinical Protection of SARS-CoV-2 S1 and N Antigens in Syrian Golden Hamster

The novel coronavirus (SARS-CoV-2) epidemic continues to be a global public crisis affecting human health. Many research groups are developing different types of vaccines to suppress the spread of SARS-CoV-2, and some vaccines have entered phase III clinical trials and have been rapidly implemented. Whether multiple antigen matches are necessary to induce a better immune response remains unclear. To address this question, this study tested the immunogenicity and protective effects of a SARS-CoV-2 recombinant S and N peptide vaccine in the Syrian golden hamster model. This experiment was based on two immunization methods: intradermal and intramuscular administration. Immunized hamsters were challenged with live SARS-CoV-2 14 days after booster immunization. Clinical symptoms were observed daily, and the antibody titer and viral load in each tissue were detected. The results showed that immunization of golden hamsters with the SARS-CoV-2 structural protein S alone or in combination with the N protein through different routes induced antibody responses, whereas immunization with the N protein alone did not. However, although the immunized hamsters exhibited partial alleviation of clinical symptoms when challenged with the virus, neither vaccine effectively inhibited the proliferation and replication of the challenging virus. In addition, the pathological damage in the immunized hamsters was similar to that in the control hamsters. Interestingly, the neutralizing antibody levels of all groups including immunized and nonimmunized animals increased significantly after viral challenge. In conclusion, the immune response induced by the experimental S and N polypeptide vaccines had no significant ability to prevent viral infection and pathogenicity in golden hamsters.

Andrographolide restored production performances and serum biochemical indexes and attenuated organs damage in Mycoplasma gallisepticum-infected broilers

1. This study aimed to study the preventive and therapeutic effects of andrographolide (Andro) during Mycoplasma gallisepticum HS strain (MG) infection in ArborAcres (AA) broilers.2. The minimum inhibitory concentration (MIC) of Andro against MG was measured. Broiler body weight, feed efficiency, morbidity, cure rate and mortality were recorded during the experiment. Air sac lesion scores and immune organ index were calculated. Expression of pMGA1.2 in lung tissue and serum biochemical indices were examined. Histopathological examinations of immune organs, liver, trachea and lung tissue were conducted by Haematoxylin and Eosin stain.3. MIC was 3.75 μg/mL and Andro significantly inhibited the expression of pMGA1.2 (P ≤ 0.05). Compared with control MG-infected group, Andro low-dose and high-dose prevention reduced the morbidity of chronic respiratory disease in 40.00% and 50.00%, respectively. Mortality of C, D and E group was 16.67%, 10.00% and 6.67%, respectively. Cure rate of E, F, G and H group was 92.00%, 92.86%, 93.33% and 100.0%, respectively. Compared with control MG-infected group, Andro treatment significantly increased average weight gain (AWG), relative weight gain rate (RWG) and feed conversion rate (FCR) at 18 to 24 days (P ≤ 0.05). Compared with control group, Andro alone treatment significantly increased AWG in broilers (P ≤ 0.05).4. Compared with control MG-infected group, Andro significantly attenuated MG-induced air sac lesion, immune organs, liver, trachea and lung damage in broilers. Andro alone treatment did not induce abnormal morphological changes in these organs in healthy broilers. Serum biochemical analysis results showed, comparing with control MG-infected group, Andro significantly decreased the content of total protein, albumin, globulin, alanine aminotransferase, aspartate aminotransferase, total bilirubin, urea, creatinine, uric acid, total cholesterol, and increased the albumin/globulin ratio and content of alkaline phosphatase, apolipoprotein B and apolipoprotein A-I in a dose-dependent manner (P ≤ 0.05).5. Andro could act as a potential agent against MG infection in broilers.

Absence of active systemic anaphylaxis in guinea pigs upon intramuscular injection of inactivated SARS-CoV-2 vaccine (Vero cells)

Background: The safety of novel vaccines against COVID-19 is currently a major focus of preclinical research. As a part of the safety evaluation testing package, 24 healthy guinea pigs were used to determine whether repeated administration of inactivated SARS-CoV-2 vaccine could induce active systemic anaphylaxis (ASA), and to evaluate its degree of severity.Method: According to sex and body weight, the animals were randomly divided into three experimental groups (eight animals per group). The negative control group received 0.9% sodium chloride (priming dose: 0.5 mL/animal; challenge dose: 1 mL/animal); the positive control group received 10% ovalbumin (priming dose: 0.5 mL/animal; challenge dose: 1 mL/animal); and the inactivated SARS-CoV-2 vaccine group received inactivated SARS-CoV-2 vaccines (priming dose: 100 U in 0.5 mL/animal; challenge dose: 200 U in 1 mL/animal). Priming dose administration was conducted by multi-point injection into the muscles of the hind limbs, three times, once every other day. On days 14 and 21 after the final priming injection, a challenge test was conducted. Half of the animals in each group were injected intravenously with twice the dose and volume of the tested substance used for immunization. During the experimental course, the injection site, general clinical symptoms, body weight, and systemic allergic reaction symptoms were monitored.Result: After intramuscular injection of inactivated SARS-CoV-2 vaccine, there were no abnormal reactions at the injection site, clinical symptoms, or deaths. There was no difference in body weight between the groups, and there were no allergic reactions. Conclusion: Thus, inactivated SARS-CoV-2 vaccine injected intramuscularly in guinea pigs did not produce ASA and had a good safety profile, which can provide actual data on vaccine risks and important reference data for clinical research on this vaccine.

Characterization of the Immunologic Phenotype of Dendritic Cells Infected With Herpes Simplex Virus 1

Due to viral envelope glycoprotein D binding to cellular membrane HVEM receptor, HSV-1 can infect certain dendritic cells, which becomes an event in the viral strategy to interfere with the host’s immune system. We previously generated the HSV-1 mutant strain M6, which produced an attenuated phenotype in mice and rhesus monkeys. The attenuated M6 strain was used to investigate how HSV-1 infection of dendritic cells interferes with both innate and adaptive immunity. Our study showed that dendritic cells membrane HVEM receptors could mediate infection of the wild-type strain and attenuated M6 strain and that dendritic cells infected by both viruses in local tissues of animals exhibited changes in transcriptional profiles associated with innate immune and inflammatory responses. The infection of pDCs and cDCs by the two strains promoted cell differentiation to the CD103+ phenotype, but varied transcriptional profiles were observed, implying a strategy that the HSV-1 wild-type strain interferes with antiviral immunity, probably due to viral modification of the immunological phenotype of dendritic cells during processing and presentation of antigen to T cells, leading to a series of deviations in immune responses, ultimately generating the deficient immune phenotype observed in infected individuals in the clinical.

Immunogenicity and safety of the inactivated enterovirus 71 vaccine administered concomitantly with the measles-rubella vaccine in infants aged 8 months in China: A noninferiority randomized controlled trial

BACKGROUND

To evaluate the immunogenicity and safety of simultaneous administration of the enterovirus 71 (EV71) vaccine with the measles and rubella (MR) combined vaccine.

METHODS

In this phase 4, randomized, open-label and noninferiority study, a total of 680 infants aged 8 months were enrolled and assigned to the simultaneous administration group (infants received the first dose of EV71 vaccine and MR vaccine on Day 0, and the second dose of EV71 vaccine on Day 28), or the separate administration groups (EV71 group: infants received two doses of EV71 vaccine on Day 0 and Day 28, respectively; MR group: infants received MR vaccine on Day 0). Blood sample was obtained on Day 0 and Day 56 to measure antibody responses to each of the antigens in terms of antibody titer or concentration, respectively. Local and systemic adverse reactions (ARs) and other adverse events (AEs) following each dose were monitored and compared among groups.

RESULTS

After vaccination, simultaneous administration group showed similar seroconversion rates of antibody against EV71(97.9%), measles (97.4%), and rubella (94.3%) compared to EV71 group (99.6% for anti-EV71) or MR group (98.4% for anti-measles and 98.9% for anti-rubella, respectively). Noninferiority was demonstrated for all antibodies as the lower limits of two-sided 97.5% confidence intervals (CIs) of the difference in seroconversion rates between simultaneous administration group and separate administration groups were above the predefined margin of -10%. Additionally, the adverse reaction rates were comparable among groups (54.4% in the simultaneous group versus 43.9% in the MR group versus 52.6% in the EV71 group).

CONCLUSION

Antibody responses induced by simultaneous administration of EV71 vaccine with MR vaccine were robust and noninferior to those by single administration alone. Like the previous findings by single administration alone, simultaneous administration demonstrated comparable reactogenicity and safety profiles.

Effects of wearing personal protective equipment during COVID-19 pandemic on composition and diversity of skin bacteria and fungi of medical workers

BACKGROUND

During the COVID-19 pandemic, wearing PPE can induce skin damage such as erythema, pruritus, erosion, and ulceration among others. Although the skin microbiome is considered important for skin health, the change of the skin microbiome after wearing PPE remain unknown.

OBJECTIVE

The present study aimed to characterize the diversity and structure of bacterial and fungal flora on skin surfaces of healthcare workers wearing personal protective equipment (PPE) during the COVID-19 pandemic using metagenomic next-generation sequencing (mNGS).

METHODS

A total of 10 Chinese volunteers were recruited and the microbiome of their face, hand, and back were analyzed before and after wearing PPE. Moreover, VISIA was used to analyze skin features.

RESULTS

Results of alpha bacterial diversity showed that there was statistically significant decrease in alpha diversity indice in the skin samples from face, hand, and three sites after wearing PPE as compared with the indice in the skin samples before wearing PPE. Further, the results of evaluated alpha fungal diversity show that there was a statistically significant decrease in alpha diversity indices in the skin samples from hand after wearing PPE as compared with the indices in the skin samples before wearing PPE (P<0.05). Results of the current study found that the main bacteria on the face, hand, and back skin samples before wearing the PPE were Propionibacterium spp. (34.04%), Corynebacterium spp. (13.12%), and Staphylococcus spp. (38.07%). The main bacteria found on the skin samples after wearing the PPE were Staphylococcus spp. (31.23%), Xanthomonas spp. (26.21%), and Cutibacterium spp. (42.59%). The fungal community composition was similar in three skin sites before and after wearing PPE.

CONCLUSION

It was evident that wearing PPE may affect the skin microbiota, especially bacteria. Therefore, it was evident that the symbiotic microbiota may reflect the skin health of medical workers during the COVID-19 pandemic.

Preclinical immunological evaluation of an intradermal heterologous vaccine against SARS-CoV-2 variants

The recent emergence of COVID-19 variants has necessitated the development of new vaccines that stimulate the formation of high levels of neutralizing antibodies against S antigen variants. A new strategy involves the intradermal administration of heterologous vaccines composed of one or two doses of inactivated vaccine and a booster dose with the mutated S1 protein (K-S). Such vaccines improve the immune efficacy by increasing the neutralizing antibody titers and promoting specific T cell responses against five variants of the RBD protein. A viral challenge test with the B.1.617.2 (Delta) variant confirmed that both administration schedules (i.e. “1 + 1” and “2 + 1”) ensured protection against this strain. These results suggest that the aforementioned strategy is effective for protecting against new variants and enhances the anamnestic immune response in the immunized population.

Ameliorated immunity elicited by intradermal inoculation in individuals vaccinated with inactivated SARS-CoV-2 vaccine

In clinical trials, antibodies against SARS-CoV-2 were almost eliminated in participants six months after immunization with an inactivated SARS-CoV-2 vaccine. The short duration of antibody persistence is an urgent problem. In this study, the problem was solved by intradermal inoculation with trace antigen. Within 72 h after intradermal inoculation, slight inflammatory reactions, such as redness and swelling, were observed at the inoculation site of the participants. On the 7th, 60th and 180th days after inoculation, the antibodies of the participants were detected, and it was found that the neutralizing antibody and ELISA (IgGs) anti-S antibody levels rapidly increased and were maintained for 6 months. These results indicate that there was a SARS-CoV-2-specific immune response in the participants immunized with an inactivated SARS-CoV-2 vaccine, which could be quickly and massively activated by intradermal trace antigen inoculation to produce an effective clinically protective effect.

Waning antibodies from inactivated SARS-CoV-2 vaccination offer protection against infection without antibody-enhanced immunopathology in rhesus macaque pneumonia models

Inactivated coronaviruses, including severe acute respiratory syndrome coronavirus 1 (SARS-CoV-1) and Middle East respiratory syndrome coronavirus (MERS-CoV), as potential vaccines have been reported to result in enhanced respiratory diseases (ERDs) in murine and nonhuman primate (NHP) pneumonia models after virus challenge, which poses great safety concerns of antibody-dependent enhancement (ADE) for the rapid wide application of inactivated SARS-CoV-2 vaccines in humans, especially when the neutralizing antibody levels induced by vaccination or initial infection quickly wane to nonneutralizing or subneutralizing levels over the time. With passive transfer of diluted postvaccination polyclonal antibodies to mimic the waning antibody responses after vaccination, we found that in the absence of cellular immunity, passive infusion of subneutralizing or nonneutralizing anti-SARS-CoV-2 antibodies could still provide some level of protection against infection upon challenge, and no low-level antibody-enhanced infection was observed. The anti-SARS-CoV-2 IgG-infused group and control group showed similar, mild to moderate pulmonary immunopathology during the acute phase of virus infection, and no evidence of vaccine-related pulmonary immunopathology enhancement was found. Typical immunopathology included elevated MCP-1, IL-8 and IL-33 in bronchoalveolar lavage fluid; alveolar epithelial hyperplasia; and exfoliated cells and mucus in bronchioles. Our results corresponded with the recent observations that no pulmonary immunology was detected in preclinical studies of inactivated SARS-CoV-2 vaccines in either murine or NHP pneumonia models or in large clinical trials and further supported the safety of inactivated SARS-CoV-2 vaccines.

SARS-CoV-2 inactivated vaccine (Vero cells) shows good safety in repeated administration toxicity test of Sprague Dawley rats

The outbreak of COVID-19 has posed a serious threat to global public health. Vaccination may be the most effective way to prevent and control the spread of the virus. The safety of vaccines is the focus of preclinical research, and the repeated dose toxicity test is the key safety test to evaluate the vaccine before clinical trials. The purpose of this study was (i) to observe the toxicity and severity of an inactivated SARS-CoV-2 vaccine (Vero cells) in rodent Sprague Dawley rats after multiple intramuscular injections under the premise of Good Laboratory Practice principles and (ii) to provide a basis for the formulation of a clinical trial scheme. The results showed that all animals in the experimental group were in good condition, no regular changes related to the vaccine were found in the detection of various toxicological indexes, and no noticeable stimulating reaction related to the vaccine was found in the injected local tissues. The neutralizing antibodies in the low- and high-dose vaccine groups began to appear 14 days after the last administration. In the negative control group, no neutralizing antibodies were observed from the administration period to the recovery period. Therefore, the repeated administration toxicity test of the inactivated SARS-CoV-2 vaccine (Vero cells) in Sprague Dawley rats showed no obvious toxic reaction. It was preliminarily confirmed that the vaccine can stimulate production of neutralizing antibodies and is safe in Sprague Dawley rats.

Intensified antibody response elicited by boost suggests immune memory in individuals administered two doses of SARS-CoV-2 inactivated vaccine

Neutralizing antibodies in the subjects of an inactivated SARS-CoV-2 vaccine clinical trial showed a decreasing trend over months. An investigation studying the third immunization suggested that the waning of neutralizing antibodies in individuals administered two doses of inactivated vaccine does not mean the disappearance of immunity.

Immunological Identification and Characterization of the Capsid Scaffold Protein Encoded by UL26.5 of Herpes Simplex Virus Type 2

Herpes simplex virus type 2 (HSV2), a pathogen that causes genital herpes lesions, interferes with the host immune system via various known and unknown mechanisms. This virus has been used to study viral antigenic composition. Convalescent serum from HSV2-infected patients was used to identify viral antigens via 2-D protein electrophoresis and immunoblotting. The serum predominantly recognized several capsid scaffold proteins encoded by gene UL26.5, mainly ICP35. This protein has been primarily reported to function temporarily in viral assembly but is not expressed in mature virus particles. Further immunological studies suggested that this protein elicits specific antibody and cytotoxic T lymphocyte (CTL) responses in mice, but these responses do not result in a clinical protective effect in response to HSV2 challenge. The data suggested that immunodominance of ICP35 might be used to design an integrated antigen with other viral glycoproteins.

Effectiveness and Safety of an Inactivated Enterovirus 71 Vaccine in Children Aged 6-71 Months in a Phase IV Study

BACKGROUND

Evaluation of a licensed inactivated enterovirus type 71 (EV71) vaccine is needed in a phase IV study with a large population to identify its effectiveness and safety for further application.

METHODS

An open-label, controlled trial involving a large population of 155 995 children aged 6-71 months was performed; 40 724 were enrolled in the vaccine group and received 2 doses of inactivated EV71 vaccine at an interval of 1 month, and the remaining children were used as the control group. The EV71-infected cases with hand, foot, and mouth disease were monitored in the vaccine and control groups during a follow-up period of 14 months since the 28th day postinoculation through the local database of the Notifiable Infectious Diseases Network. The effectiveness of the vaccine was estimated by comparing the incidence density in the vaccine group versus that in the control group based upon EV71-infected patients identified via laboratory testing. In parallel, the active and passive surveillance for safety of the vaccine was conducted by home or telephone visits and by using the Adverse Event Following Immunization (AEFI) system, respectively.

RESULTS

An overall level of 89.7% (95% confidence interval, 24.0-98.6%) vaccine effectiveness against EV71 infection and a 4.58% rate of reported adverse events were observed. Passive surveillance demonstrated a 0.31% rate of reported common minor reactions.

CONCLUSIONS

The clinical protection and safety of the EV71 vaccine were demonstrated in the immunization of a large population.

CLINICAL TRIALS REGISTRATION

NCT03001986.

The safety and immunogenicity of an inactivated SARS-CoV-2 vaccine in Chinese adults aged 18-59 years: A phase I randomized, double-blinded, controlled trial

Background

This study examined the safety and immunogenicity of an inactivated SARS-CoV-2 vaccine.

Method

In a phase I randomized, double-blinded, placebo-controlled trial involving 192 healthy adults 18–59 years old, two injections of three doses (50 EU, 100 EU, 150 EU) of an inactivated SARS-CoV-2 vaccine or placebo were administered intramuscularly at a 2- or 4-week interval. The safety and immunogenicity of the vaccine were evaluated.

Results

Vaccination was completed in 191 subjects. Forty-four adverse reactions occurred within 28 days, most commonly mild pain and redness at the injection site or slight fatigue. At days 14 and 28, the seroconversion rates were 87.5% and 79.2% (50 EU), 100% and 95.8% (100 EU), and 95.8% and 87.5% (150 EU), respectively, with geometric mean titers (GMTs) of 18.1 and 10.6, 54.5 and 15.4, and 37.1 and 18.5, respectively, for the schedules with 2-week and 4-week intervals. Seroconversion was associated with synchronous upregulation of antibodies against the S protein, N protein and virion and a cytotoxic T lymphocyte (CTL) response. No cytokines and immune cells related to immunopathology were observed. Transcriptome analysis revealed the genetic diversity of immune responses induced by the vaccine.

Interpretation

In a population aged 18–59 years in this trial, this inactivated SARS-CoV-2 vaccine was safe and immunogenic.

Trial registration: CTR20200943 and NCT04412538.

Astrocyte-Derived Exosomes in an iPSC Model of Bipolar Disorder

Bipolar I Disorder (BP) is a serious, recurrent mood disorder that is characterized by alternating episodes of mania and depression. To begin to identify novel approaches and pathways involved in BP, we have obtained skin samples from BP patients and undiagnosed control (C) individuals, reprogrammed them to form induced pluripotent stem cells (iPSC), and then differentiated the stem cells into astrocytes. RNAs from BP and C astrocytes were extracted and RNAseq analysis carried out. 501 differentially expressed genes were identified, including genes for cytoskeletal elements, extracellular matrix, signaling pathways, neurodegeneration, and notably transcripts that identify exosomes. When we compared highly expressed genes using hierarchial cluster analysis, "Exosome" was the first and most highly significant cluster identified, p < 5 × 10^-13, Benjamini correction. Exosomes are membrane-bound vesicles that package and remove toxic proteins from cells and also enable cell to cell communication. They carry genetic material, including DNA, mRNA and microRNAs, proteins, and lipids to target cells throughout the body. Exosomes are released by cortical neurons and astrocytes in culture and are present in BP vs C postmortem brain tissue. Little is known about what transcripts and proteins are targeted to neurons, how they regulate biological functions of the acceptor cell, or how that may be altered in mood disorders. Since astrocyte-derived exosomes have been suggested to promote neuronal plasticity, as well as to remove toxic proteins in the brain, alterations in their function or content may be involved in neurodevelopmental, neuropathological, and neuropsychiatric conditions. To examine exosome cargos and interactions with neural precursor cells, astrocytes were differentiated from four bipolar disorder (BP) and four control (C) iPSC lines. Culture supernatants from these astrocytes were collected, and exosomes isolated by ultra-centrifugation. Western blot analysis demonstrated the presence of the exosome markers CD9, CD81, and Hsp70. Nanosight technology was used to characterize exosomes from each astrocyte cell line, suggesting that exosomes were slightly more concentrated in culture supernatants derived from BP compared with C astrocytes but there was no difference in the mean sizes of the exosomes. Analysis of their function in neuronal differentiation is being carried out by labeling exosomes derived from bipolar patient and control astrocytes and adding them to control neural progenitor cells. Given the current interest in clearing toxic proteins from brains of patients with neurodegenerative disorders, exosomes may present similar opportunities in BP.

Randomized, double-blinded and placebo-controlled phase II trial of an inactivated SARS-CoV-2 vaccine in healthy adults

Background

We evaluated an inactivated SARS-CoV-2 vaccine for immunogenicity and safety in adults aged 18-59 years.

Methods

In this randomized, double-blinded and controlled trial, healthy adults received a medium (MD) or a high dose (HD) of the vaccine at an interval of either 14 days or 28 days. Neutralizing antibody (NAb) and anti-S and anti-N antibodies were detected at different times, and adverse reactions were monitored for 28 days after full immunization.

Results

A total of 742 adults were enrolled in the immunogenicity and safety analysis. Among subjects in the 0, 14 procedure, the seroconversion rates of NAb in MD and HD groups were 89% and 96% with GMTs of 23 and 30, respectively, at day 14 and 92% and 96% with GMTs of 19 and 21, respectively at day 28 after immunization. Anti-S antibodies had GMTs of 1883 and 2370 in MD and 2295 and 2432 in HD group. Anti-N antibodies had GMTs of 387 and 434 in MD group and 342 and 380 in HD group. Among subjects in the 0, 28 procedure, seroconversion rates for NAb at both doses were both 95% with GMTs of 19 at day 28 after immunization. Anti-S antibodies had GMTs of 937 and 929 for MD and HD group, and anti-N antibodies had GMTs of 570 and 494 for MD and HD group, respectively. No serious adverse events were observed during the study period.

Conclusion

Adults vaccinated with inactivated SARS-CoV-2 vaccine had NAb as well as anti-S/N antibody, and had a low rate of adverse reactions.

Clinical trials registration

NCT04412538.

Do food and stress biomarkers work for wastewater-based epidemiology? A critical evaluation

Dietary characteristics and oxidative stress are closely linked to the wellbeing of individuals. In recent years, various urinary biomarkers of food and oxidative stress have been proposed for use in wastewater-based epidemiology (WBE), in efforts to objectively monitor the food consumed and the oxidative stress experienced by individuals in a wastewater catchment. However, it is not clear whether such biomarkers are suitable for wastewater-based epidemiology. This study presents a suite of 30 urinary food and oxidative stress biomarkers and evaluates their applicability for WBE studies. This includes 22 biomarkers which were not previously considered for WBE studies. Daily per capita loads of biomarkers were measured from 57 wastewater influent samples from nine Australian catchments. Stability of biomarkers were assessed using laboratory scale sewer reactors. Biomarkers of consumption of vitamin B2, vitamin B3 and fibre, as well as a component of citrus had per capita loads in line with reported literature values despite susceptibility of degradation in sewer reactors. Consumption biomarkers of red meat, fish, fruit, other vitamins and biomarkers of stress had per capita values inconsistent with literature findings, and/or degraded rapidly in sewer reactors, indicating that they are unsuitable for use as WBE biomarkers in the traditional quantitative sense. This study serves to communicate the suitability of food and oxidative stress biomarkers for future WBE research.

A HSV1 mutant leads to an attenuated phenotype and induces immunity with a protective effect

Herpes simplex virus type 1 (HSV1) is a complicated structural agent with a sophisticated transcription process and a high infection rate. A vaccine against HSV1 is urgently needed. As multiple viral-encoded proteins, including structural and nonstructural proteins, contribute to immune response stimulation, an attenuated or deficient HSV1 vaccine may be relatively reliable. Advances in genomic modification technologies provide reliable means of constructing various HSV vaccine candidates. Based on our previous work, an M6 mutant with mutations in the UL7, UL41, LAT, Us3, Us11 and Us12 genes was established. The mutant exhibited low proliferation in cells and an attenuated phenotype in an animal model. Furthermore, in mice and rhesus monkeys, the mutant can induce remarkable serum neutralizing antibody titers and T cell activation and protect against HSV1 challenge by impeding viral replication, dissemination and pathogenesis.

Distinct infection process of SARS-CoV-2 in human bronchial epithelial cell lines

Coronavirus disease 2019, caused by severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2), leads to a series of clinical symptoms of respiratory and pulmonary inflammatory reactions via unknown pathologic mechanisms related to the viral infection process in tracheal or bronchial epithelial cells. Investigation of this viral infection in the human bronchial epithelial cell line (16HBE) suggests that SARS‐CoV‐2 can enter these cells through interaction between its membrane‐localized S protein with the angiotensin‐converting enzyme 2 molecule on the host cell membrane. Further observation indicates distinct viral replication with a dynamic and moderate increase, whereby viral replication does not lead to a specific cytopathic effect but maintains a continuous release of progeny virions from infected cells. Although messenger RNA expression of various innate immune signaling molecules is altered in the cells, transcription of interferons‐α (IFN‐α), IFN‐β, and IFN‐γ is unchanged. Furthermore, expression of some interleukins (IL) related to inflammatory reactions, such as IL‐6, IL‐2, and IL‐8, is maintained at low levels, whereas that of ILs involved in immune regulation is upregulated. Interestingly, IL‐22, an IL that functions mainly in tissue repair, shows very high expression. Collectively, these data suggest a distinct infection process for this virus in respiratory epithelial cells, which may be linked to its clinicopathological mechanism.

SARS‐CoV‐2 does not lead to a specific cytopathic effect in 16HBE cells, but maintains continuous release of progeny virions from infected cells. During infection, IL‐22, an interleukin that functions mainly in tissue repair, showed very high expression.

Study of integrated protective immunity induced in rhesus macaques by the intradermal administration of a bivalent EV71-CA16 inactivated vaccine

Enterovirus type 71 (EV71) and coxsackievirus A 16 (CA16) are recognized as the major pathogens responsible for human hand-foot-mouth disease. To develop a bivalent EV71-CA16 vaccine, rhesus macaques immunized with two doses of this vaccine via the intradermal route were challenged with EV71 or CA16, and their clinical symptoms, viral shedding, neutralizing antibodies, IFN-γ-specific ELISpots, and tissue viral load were examined longitudinally. Specific immunity against EV71 and CA16 was observed in the macaques, which exhibited controlled proliferation of the EV71 and CA16 viruses and upregulated expression of immune-related genes compared with the controls. Furthermore, broad protection against EV71 and CA16 challenge without immunopathological effects was observed in all the immunized macaques. These studies suggest that the bivalent EV71-CA16 inactivated vaccine was effective against wild-type EV71 or CA16 viral challenge in rhesus macaques.

Immunogenicity and Safety of an F-Genotype Attenuated Mumps Vaccine in Healthy 8- to 24-Month-Old Children

Background

Mumps vaccine immunizations have reduced the incidence of this disease. With the variation of mumps circulating strain, novel vaccine strains are always important.

Methods

A 2-center parallel, randomized, double-blind noninferiority trial was performed to compare an F-genotype attenuated mumps vaccine (SP strain) to the A-genotype vaccine (S-79, Jeryl-Lynn strain) in 1080 healthy children aged 8-24 months in Hubei, China.

Results

Participants were randomly assigned to receive a high or low dose of the SP or S79 vaccine and then assessed clinically at 30 minutes and 1-28 days postinoculation. No differences in local or systemic reactivity were observed. A similar incidence of severe adverse events associated with the vaccine was observed in the high-dose group and the positive control group. Based on throat swab collections, no viral shedding was present at the 4th and 10th days in any group. Neutralizing and hemagglutination-inhibiting antibody assays with the F- or A-genotype strains showed similar trends in geometric mean titers in the high-dose SP and S79 groups. Increased cytotoxic T lymphocyte responses were observed in all groups.

Conclusions

The F-genotype attenuated mumps vaccine is safe, offers immunogenicity against a homologous virus, and is noninferior to the A-genotype vaccine in 8- to 24-month-old children.

Erratum: Author Correction: Role of innate lymphoid cells and dendritic cells in intradermal immunization of the enterovirus antigen

[This corrects the article DOI: 10.1038/s41541-019-0108-6.].

Reducing Viral Inhibition of Host Cellular Apoptosis Strengthens the Immunogenicity and Protective Efficacy of an Attenuated HSV-1 Strain

Herpes simplex virus 1 (HSV-1), a member of α herpesviruses, shows a high infectivity rate of 30%-60% in populations of various ages. Some herpes simplex (HSV) vaccine candidates evaluated during the past 20 years have not shown protective efficacy against viral infection. An improved understanding of the immune profile of infected individuals and the associated mechanism is needed. HSV uses an immune evasion strategy during viral replication, and various virus-encoded proteins, such as ICP47 and Vhs, participate in this process through limiting the ability of CD8⁺ cytotoxic T lymphocytes to recognize target cells. Other proteins, e.g., Us3 and Us5, also play a role in viral immune evasion via interfering with cellular apoptosis. In this work, to study the mechanism by which HSV-1 strain attenuation interferes with the viral immune evasion strategy, we constructed a mutant strain, M5, with deletions in the Us3 and Us5 genes. M5 was shown to induce higher neutralizing antibody titers and a stronger cellular immune response than our previously reported M3 strain, and to prevent virus infection more effectively than the M3 strain in an in vivo mouse challenge test.

The Chinese National Twin Registry: a 'gold mine' for scientific research

The Chinese National Twin Registry (CNTR) currently includes data from 61 566 twin pair from 11 provinces or cities in China. Of these, 31 705, 15 060 and 13 531 pairs are monozygotic, same-sex dizygotic and opposite-sex dizygotic pairs, respectively, determined by opposite sex or intrapair similarity. Since its establishment in 2001, the CNTR has provided an important resource for analysing genetic and environmental influences on chronic diseases especially cardiovascular diseases. Recently, the CNTR has focused on collecting biologic specimens from disease-concordant or disease-discordant twin pairs or from twin pairs reared apart. More than 8000 pairs of these twins have been registered, and blood samples have been collected from more than 1500 pairs. In this review, we summarize the main findings from univariate and multivariate genetic effects analyses, gene-environment interaction studies, omics studies exploring DNA methylation and metabolomic markers associated with phenotypes. There remains further scope for CNTR research and data mining. The plan for future development of the CNTR is described. The CNTR welcomes worldwide collaboration.