A bivalent ChAd nasal vaccine protects against SARS-CoV-2 BQ.1.1 and XBB.1.5 infection and disease in mice and hamsters

We previously described a nasally delivered monovalent adenoviral-vectored SARS-CoV-2 vaccine (ChAd-SARS-CoV-2-S, targeting Wuhan-1 spike [S]; iNCOVACC®) that is currently used in India as a primary or booster immunization. Here, we updated the mucosal vaccine for Omicron variants by creating ChAd-SARS-CoV-2-BA.5-S, which encodes for a pre-fusion and surface-stabilized S protein of the BA.5 strain, and then tested monovalent and bivalent vaccines for efficacy against circulating variants including BQ.1.1 and XBB.1.5. Whereas monovalent ChAd-vectored vaccines effectively induced systemic and mucosal antibody responses against matched strains, the bivalent ChAd-vectored vaccine elicited greater breadth. However, serum neutralizing antibody responses induced by both monovalent and bivalent vaccines were poor against the antigenically distant XBB.1.5 Omicron strain and did not protect in passive transfer experiments. Nonetheless, nasally delivered bivalent ChAd-vectored vaccines induced robust antibody and spike-specific memory T cell responses in the respiratory mucosa, and conferred protection against WA1/2020 D614G and Omicron variants BQ.1.1 and XBB.1.5 in the upper and lower respiratory tracts of both mice and hamsters. Our data suggest that a nasally delivered bivalent adenoviral-vectored vaccine induces protective mucosal and systemic immunity against historical and emerging SARS-CoV-2 strains without requiring high levels of serum neutralizing antibody.

Vaccine Protection Against the SARS-CoV-2 Omicron Variant in Macaques

BACKGROUND

The rapid spread of the SARS-CoV-2 Omicron (B.1.1.529) variant, including in highly vaccinated populations, has raised important questions about the efficacy of current vaccines. Immune correlates of vaccine protection against Omicron are not known.

METHODS

30 cynomolgus macaques were immunized with homologous and heterologous prime-boost regimens with the mRNA-based BNT162b2 vaccine and the adenovirus vector-based Ad26.COV2.S vaccine. Following vaccination, animals were challenged with the SARS-CoV-2 Omicron variant by the intranasal and intratracheal routes.

RESULTS

Omicron neutralizing antibodies were observed following the boost immunization and were higher in animals that received BNT162b2, whereas Omicron CD8+ T cell responses were higher in animals that received Ad26.COV2.S. Following Omicron challenge, sham controls showed more prolonged virus in nasal swabs than in bronchoalveolar lavage. Vaccinated macaques demonstrated rapid control of virus in bronchoalveolar lavage, and most vaccinated animals also controlled virus in nasal swabs, showing that current vaccines provide substantial protection against Omicron in this model. However, vaccinated animals that had moderate levels of Omicron neutralizing antibodies but negligible Omicron CD8+ T cell responses failed to control virus in the upper respiratory tract. Virologic control correlated with both antibody and T cell responses.

CONCLUSIONS

BNT162b2 and Ad26.COV2.S provided robust protection against high-dose challenge with the SARS-CoV-2 Omicron variant in macaques. Protection against this highly mutated SARS-CoV-2 variant correlated with both humoral and cellular immune responses.

Brain stem death induces pro-inflammatory cytokine production and cardiac dysfunction in sheep model

Introduction

Organs procured following brain stem death (BSD) are the main source of organ grafts for transplantation. However, BSD is associated with inflammatory responses that may damage the organ and affect both the quantity and quality of organs available for transplant. Therefore, we aimed to investigate plasma and bronchoalveolar lavage (BAL) pro-inflammatory cytokine profiles and cardiovascular physiology in a clinically relevant 6-h ovine model of BSD.

Methods

Twelve healthy female sheep (37–42 Kg) were anaesthetized and mechanically ventilated prior to undergoing BSD induction and then monitored for 6 h. Plasma and BAL endothelin-1 and cytokines (IL-1β, 6, 8 and tumour necrosis factor alpha (TNF-α)) were assessed by ELISA. Differential white blood cell counts were performed. Cardiac function during BSD was also examined using echocardiography, and cardiac biomarkers (A-type natriuretic peptide and troponin I were measured in plasma.

Results

Plasma concentrations big ET-1, IL-6, IL-8, TNF-α and BAL IL-8 were significantly (p < 0.01) increased over baseline at 6 h post-BSD. Increased numbers of neutrophils were observed in the whole blood (3.1 × 10⁹ cells/L [95% confidence interval (CI) 2.06–4.14] vs. 6 × 10⁹ cells/L [95%CI 3.92–7.97]; p < 0.01) and BAL (4.5 × 10⁹ cells/L [95%CI 0.41–9.41] vs. 26 [95%CI 12.29–39.80]; p = 0.03) after 6 h of BSD induction vs baseline. A significant increase in ANP production (20.28 pM [95%CI 16.18–24.37] vs. 78.68 pM [95%CI 53.16–104.21]; p < 0.0001) and cTnI release (0.039 ng/mL vs. 4.26 [95%CI 2.69–5.83] ng/mL; p < 0.0001), associated with a significant reduction in heart contractile function, were observed between baseline and 6 h.

Conclusions

BSD induced systemic pro-inflammatory responses, characterized by increased neutrophil infiltration and cytokine production in the circulation and BAL fluid, and associated with reduced heart contractile function in ovine model of BSD.

Estrogen Hormone Is an Essential Sex Factor Inhibiting Inflammation and Immune Response in COVID-19

Although vaccines have been evaluated and approved for SARS-CoV-2 infection prevention, there remains a lack of effective treatments to reduce the mortality of COVID-19 patients already infected with SARS-CoV-2. The global data of COVID-19 showed that men have a higher mortality rate than women. We further observed that the proportion of mortality of female increases starting from around the age of 55 significantly. Thus, sex is an essential factor associated with COVID-19 mortality, and sex related genetic factors could be interesting mechanisms and targets for COVID-19 treatment. However, the associated sex factors and signaling pathways remain unclear. Here, we propose to uncover the potential sex associated factors using systematic and integrative network analysis. The unique results indicated that estrogen hormones (ER), e.g., estrone and estriol, 1) interacting with ESR1/2 receptors, 2) can inhibit SARS-CoV-2 caused inflammation and immune response signaling in host cells; and 3) estrogen hormone is associated with the distinct fatality rates between male and female COVID-19 patients. Specifically, a high level of estradiol protecting young female COVID-19 patients, and estrogen loss to an extremely low level in females after about 55 years of age causing the increased fatality rate of women. In conclusion, estrogen hormone, interacting with ESR1/2 receptors, is an essential sex factor that protects COVID-19 patients by inhibiting inflammation and immune response caused by SARS-CoV-2 infection. Medications perturb the down-stream of ESR1/ESR2 to inhibit the inflammation and immune response can be effective or synergistic combined with other existing drugs for COVID-19 treatment.

JIB-04 has broad-spectrum antiviral activity and inhibits SARS-CoV-2 replication and coronavirus pathogenesis

Pathogenic coronaviruses represent a major threat to global public health. Here, using a recombinant reporter virus-based compound screening approach, we identified several small-molecule inhibitors that potently block the replication of the newly emerged severe acute respiratory syndrome virus 2 (SARS-CoV-2). Among them, JIB-04 inhibited SARS-CoV-2 replication in Vero E6 cells with an EC50 of 695 nM, with a specificity index of greater than 1,000. JIB-04 showed in vitro antiviral activity in multiple cell types against several DNA and RNA viruses, including porcine coronavirus transmissible gastroenteritis virus. In an in vivo porcine model of coronavirus infection, administration of JIB-04 reduced virus infection and associated tissue pathology, which resulted in improved weight gain and survival. These results highlight the potential utility of JIB-04 as an antiviral agent against SARS-CoV-2 and other viral pathogens.

Distinct peripheral inflammatory profiles distinguish COVID-19 from influenza infection, with limited contributions from cytokine storm

We developed a prospective observational cohort of COVID-19 and influenza patients to assess the quality and magnitude of their immune responses at the cellular and protein levels. Although COVID-19 patients exhibited equivalent lymphocyte counts compared to influenza patients, they had fewer monocytes and lower surface HLA-class II expression on select monocyte populations compared to influenza patients and healthy controls. Decreased HLA-DR on intermediate monocytes was a significant predictor of COVID-19 disease severity. Protein cytokine levels were measured in two distinct COVID-19 cohorts, composed of 73 and 89 patients, revealing multiple inflammatory phenotypes. Only four percent of patients (7 of 162) exhibited a distinct Cytokine Storm Syndrome (CSS) phenotype. Furthermore, COVID-19 patients generally exhibited lower cytokine levels than influenza patients. Upregulation of a few innate inflammatory mediators, including IL-6, GCSF, IL-1RA, and MCP1, predicted death from acute respiratory failure among COVID-19 patients but were not statistically higher than those of influenza patients. Single-cell transcriptional profiling of 2 healthy controls as well as 3 COVID-19 and 3 influenza subjects with respiratory failure was concordant with the profound suppression in type I and type II interferon signaling in COVID-19 patients across multiple cell types. In contrast, COVID-19 cells were enriched for alterations in metabolic, stress, and apoptotic pathways. When considered across the spectrum of peripheral innate and adaptive immune profiles, the immune pathologies underlying severe influenza and COVID-19 are substantially distinct, with COVID-19 patients generally less inflamed than those with influenza.

Endothelin receptor antagonist improves donor lung function in an ex vivo perfusion system

BACKGROUND

A lung transplant is the last resort treatment for many patients with advanced lung disease. The majority of donated lungs come from donors following brain death (BD). The endothelin axis is upregulated in the blood and lung of the donor after BD resulting in systemic inflammation, lung damage and poor lung graft outcomes in the recipient. Tezosentan (endothelin receptor blocker) improves the pulmonary haemodynamic profile; however, it induces adverse effects on other organs at high doses. Application of ex vivo lung perfusion (EVLP) allows the development of organ-specific hormone resuscitation, to maximise and optimise the donor pool. Therefore, we investigate whether the combination of EVLP and tezosentan administration could improve the quality of donor lungs in a clinically relevant 6-h ovine model of brain stem death (BSD).

METHODS

After 6 h of BSD, lungs obtained from 12 sheep were divided into two groups, control and tezosentan-treated group, and cannulated for EVLP. The lungs were monitored for 6 h and lung perfusate and tissue samples were processed and analysed. Blood gas variables were measured in perfusate samples as well as total proteins and pro-inflammatory biomarkers, IL-6 and IL-8. Lung tissues were collected at the end of EVLP experiments for histology analysis and wet-dry weight ratio (a measure of oedema).

RESULTS

Our results showed a significant improvement in gas exchange [elevated partial pressure of oxygen (P = 0.02) and reduced partial pressure of carbon dioxide (P = 0.03)] in tezosentan-treated lungs compared to controls. However, the lungs hematoxylin-eosin staining histology results showed minimum lung injuries and there was no difference between both control and tezosentan-treated lungs. Similarly, IL-6 and IL-8 levels in lung perfusate showed no difference between control and tezosentan-treated lungs throughout the EVLP. Histological and tissue analysis showed a non-significant reduction in wet/dry weight ratio in tezosentan-treated lung tissues (P = 0.09) when compared to control.

CONCLUSIONS

These data indicate that administration of tezosentan could improve pulmonary gas exchange during EVLP.

Viral MHC class I inhibition evades protective tissue-resident memory CD8+ T cells (TRM) and influences TRM immunodominance within specific niches

Tissue-resident memory CD8+ T cells (TRM) confer rapid protection and immunity against viral infections. Many viruses have evolved mechanisms to inhibit MHCI presentation in order to evade effector CD8+ T cells, suggesting that these mechanisms may also apply to TRM-mediated protection. However, the effects of viral MHCI inhibition on the function and generation of TRM is unknown. We show that viral MHCI inhibition dampens immunodominance within the lung TRM pool, indicating an effect on the TRM repertoire, but this effect was not observed in the skin. In the presence of viral MHCI inhibition, the overall development of TRM is unaffected, yet is unexpectedly enhanced with local cognate antigen, while local cognate antigen is not required for TRM maintenance. Moreover, viral MHCI inhibition efficiently evades TRM effector functions. These findings suggest that vaccine strategies involving pure T-cell approaches may provide poor efficacy against viruses that target the MHCI pathway.

Bilirubin scavenges chloramines and inhibits myeloperoxidase-induced protein/lipid oxidation in physiologically relevant hyperbilirubinemic serum

Hypochlorous acid (HOCl), an oxidant produced by myeloperoxidase (MPO), induces protein and lipid oxidation, which is implicated in the pathogenesis of atherosclerosis. Individuals with mildly elevated bilirubin concentrations (i.e., Gilbert syndrome; GS) are protected from atherosclerosis, cardiovascular disease, and related mortality. We aimed to investigate whether exogenous/endogenous unconjugated bilirubin (UCB), at physiological concentrations, can protect proteins/lipids from oxidation induced by reagent and enzymatically generated HOCl. Serum/plasma samples supplemented with exogenous UCB (≤250µM) were assessed for their susceptibility to HOCl and MPO/H2O2/Cl(-) oxidation, by measuring chloramine, protein carbonyl, and malondialdehyde (MDA) formation. Serum/plasma samples from hyperbilirubinemic Gunn rats and humans with GS were also exposed to MPO/H2O2/Cl(-) to: (1) validate in vitro data and (2) determine the relevance of endogenously elevated UCB in preventing protein and lipid oxidation. Exogenous UCB dose-dependently (P<0.05) inhibited HOCl and MPO/H2O2/Cl(-)-induced chloramine formation. Albumin-bound UCB efficiently and specifically (3.9-125µM; P<0.05) scavenged taurine, glycine, and N-α-acetyllysine chloramines. These results were translated into Gunn rat and GS serum/plasma, which showed significantly (P<0.01) reduced chloramine formation after MPO-induced oxidation. Protein carbonyl and MDA formation was also reduced after MPO oxidation in plasma supplemented with UCB (P<0.05; 25 and 50µM, respectively). Significant inhibition of protein and lipid oxidation was demonstrated within the physiological range of UCB, providing a hypothetical link to protection from atherosclerosis in hyperbilirubinemic individuals. These data demonstrate a novel and physiologically relevant mechanism whereby UCB could inhibit protein and lipid modification by quenching chloramines induced by MPO-induced HOCl.

Influenza A antigen exposure selects dominant Vbeta17+ TCR in human CD8+ cytotoxic T cell responses

During acute human viral infections, such as influenza A, specific cytotoxic T lymphocytes (CTL) are generated which aid virus clearance. We have observed that in HLA-A*0201+ subjects, CTL expressing Vbeta17+ TCR and recognizing a peptide from the influenza A matrix protein (M1(58-66)) dominate this response. In experimental models of infection such dominance can be due to inheritance of a restricted T cell repertoire or acquired consequent on expansion of CTL bearing an optimum TCR conformation against the MHC-peptide complex. To examine how influenza A infection might influence the development of TCR Vbeta17 expansion, we studied influenza A-specific CTL in a cross-sectional study of 82 HLA-A*0201+ individuals from birth (cord blood) to adulthood. Primary M1(58-66) -specific CTL were detected in cord blood, but their TCR were diverse and depletion of Vbeta17+ cells did not abrogate specific cytotoxicity. In contrast following natural influenza A infection, TCR Vbeta17+ CTL dominated to the extent that only one of nine adult CTL lines retained any functional activity after in vitro depletion of Vbeta17+ CTL. These results suggest that the dominance of Vbeta17+ TCR among adult M1(58-66)-specific CTL results from maturation and focussing of the response driven by exposure to influenza, and have implications for optimum immunization strategies.

Detection of influenza a subtypes in community-based surveillance

A rapid microtitre cell enzyme immuno assay (cell-EIA) was developed for the detection of influenza A subtypes in nasopharyngeal(NPS) swabs taken for surveillance. During the 1997/1998 influenza season in the United Kingdom, cell-EIA was compared to cell culture for the detection and typing of influenza A viruses in NPS obtained by sentinel general practitioners in community surveillance. The cell EIA can also be used to detect different influenza A subtypes (H3N2, H1N1, H5N3, H5N1, H7N7, and H9N2) and was used as a rapid detection assay for the screening of individuals returning from Hong Kong with influenza-like illness suspected to be due to H5N1 in 1997/98, providing a rapid, efficient, inexpensive method for the screening of influenza A cases during an outbreak or pandemic situation. The cell-EIA results reflected the results obtained by traditional virus culture within the age distribution of samples, clinical symptoms, and time between date of illness onset and sampling of cases, indicating its usefulness in surveillance of human and non-human influenza viruses. During two outbreaks of influenza in schools, Directigen Flu-A, a near patient test, the cell-EIA, and tissue culture were compared. The cell-EIA gave higher sensitivity and specificity (74% and 90%) than Directigen Flu-A (65% and 84.6%) in comparison with cell culture.

Influenza virus infection in the second and third trimesters of pregnancy: a clinical and seroepidemiological study

OBJECTIVE

To determine whether maternal influenza virus infection in the second and third trimesters of pregnancy results in transplacental transmission of infection, maternal auto-antibody production or an increase in complications of pregnancy.

DESIGN

Case-control cohort study.

POPULATION

Study and control cohorts were derived from 3,975 women who were consecutively delivered at two Nottingham teaching hospitals between May 1993 and July 1994. A complete set of three sera was available for 1,659 women.

METHODS

Paired maternal ante- and postnatal sera were screened for a rise in anti-influenza virus antibody titre by single radial haemolysis and haemagglutination inhibition. Routine obstetric data collected during and after pregnancy were retrieved from the Nottingham obstetric database. Cord samples were tested for the presence of IgM anti-influenza antibodies, and postnatal infant sera were tested for the persistence of influenza-virus specific IgG. Paired antenatal and postnatal sera were tested against a standard range of auto-antigens by immunofluorescence.

MAIN OUTCOME MEASURES

Classification of women as having definite serological evidence of an influenza virus infection in pregnancy (cases) or as controls.

RESULTS

Intercurrent influenza virus infections were identified in 182/1,659 (11.0%) pregnancies. None of 138 cord sera from maternal influenza cases was positive for influenza A virus specific IgM. IgG anti-influenza antibodies did not persist in any of 12 infant sera taken at age 6-12 months. Six of 172 postnatal maternal sera from cases of influenza were positive for auto-antibodies. In all cases the corresponding antenatal serum was also positive for the same auto-antibody. There were no significant differences in pregnancy outcome measures between cases and controls. Overall, there were significantly more complications of pregnancy in the cases versus the controls, but no single type of complication achieved statistical significance.

CONCLUSIONS

Influenza infection in the second and third trimesters of pregnancy is a relatively common event. We found no evidence for transplacental transmission of influenza virus or auto-antibody production in pregnancies complicated by influenza infections. There was an increase in the complications of pregnancy in our influenza cohort.