ChAdOx1 nCoV-19 (AZD1222) or nCoV-19-Beta (AZD2816) protect Syrian hamsters against Beta Delta and Omicron variants.

ChAdOx1 nCoV-19 (AZD1222) is a replication-deficient simian adenovirus-vectored vaccine encoding the spike (S) protein of SARS-CoV-2, based on the first published full-length sequence (Wuhan-1). AZD1222 has been shown to have 74% vaccine efficacy against symptomatic disease in clinical trials. However, variants of concern (VoCs) have been detected, with substitutions that are associated with a reduction in virus neutralizing antibody titer. Updating vaccines to include S proteins of VoCs may be beneficial, even though current real-world data is suggesting good efficacy following boosting with vaccines encoding the ancestral S protein. Using the Syrian hamster model, we evaluate the effect of a single dose of AZD2816, encoding the S protein of the Beta VoC, and efficacy of AZD1222/AZD2816 as a heterologous primary series against challenge with the Beta or Delta variant. Minimal to no viral sgRNA could be detected in lungs of vaccinated animals obtained at 3- or 5- days post inoculation, in contrast to lungs of control animals. In Omicron-challenged hamsters, a single dose of AZD2816 or AZD1222 reduced virus shedding. Thus, these vaccination regimens are protective against the Beta, Delta, and Omicron VoCs in the hamster model.

Efficacy of ChAdOx1 vaccines against SARS-CoV-2 Variants of Concern Beta, Delta and Omicron in the Syrian hamster model.

ChAdOx1 nCoV-19 (AZD1222) is a replication-deficient simian adenovirusâ€"vectored vaccine encoding the spike (S) protein of SARS-CoV-2, based on the first published full-length sequence (Wuhan-1). AZD1222 was shown to have 74% vaccine efficacy (VE) against symptomatic disease in clinical trials and over 2.5 billion doses of vaccine have been released for worldwide use. However, SARS-CoV-2 continues to circulate and consequently, variants of concern (VoCs) have been detected, with substitutions in the S protein that are associated with a reduction in virus neutralizing antibody titer. Updating vaccines to include S proteins of VoCs may be beneficial over boosting with vaccines encoding the ancestral S protein, even though current real-world data is suggesting good efficacy against hospitalization and death following boosting with vaccines encoding the ancestral S protein. Using the Syrian hamster model, we evaluated the effect of a single dose of AZD2816, encoding the S protein of the Beta VoC, and efficacy of AZD1222/AZD2816 as a heterologous primary series against challenge with the Beta or Delta variant. We then investigated the efficacy of a single dose of AZD2816 or AZD1222 against the Omicron VoC. As seen previously, minimal to no viral sgRNA could be detected in lungs of vaccinated animals obtained at 5 days post inoculation, in contrast to lungs of control animals. Thus, these vaccination regimens are protective against the Beta, Delta, and Omicron VoCs in the hamster model.

ChAdOx1-vectored Lassa fever vaccine elicits a robust cellular and humoral immune response and protects guinea pigs against lethal Lassa virus challenge.

Lassa virus (LASV) infects hundreds of thousands of individuals each year, highlighting the need for the accelerated development of preventive, diagnostic, and therapeutic interventions. To date, no vaccine has been licensed for LASV. ChAdOx1-Lassa-GPC is a chimpanzee adenovirus-vectored vaccine encoding the Josiah strain LASV glycoprotein precursor (GPC) gene. In the following study, we show that ChAdOx1-Lassa-GPC is immunogenic, inducing robust T-cell and antibody responses in mice. Furthermore, a single dose of ChAdOx1-Lassa-GPC fully protects Hartley guinea pigs against morbidity and mortality following lethal challenge with a guinea pig-adapted LASV (strain Josiah). By contrast, control vaccinated animals reached euthanasia criteria 10-12 days after infection. Limited amounts of LASV RNA were detected in the tissues of vaccinated animals. Viable LASV was detected in only one animal receiving a single dose of the vaccine. A prime-boost regimen of ChAdOx1-Lassa-GPC in guinea pigs significantly increased antigen-specific antibody titers and cleared viable LASV from the tissues. These data support further development of ChAdOx1-Lassa-GPC and testing in non-human primate models of infection.

K18-hACE2 mice develop respiratory disease resembling severe COVID-19.

SARS-CoV-2 emerged in late 2019 and resulted in the ongoing COVID-19 pandemic. Several animal models have been rapidly developed that recapitulate the asymptomatic to moderate disease spectrum. Now, there is a direct need for additional small animal models to study the pathogenesis of severe COVID-19 and for fast-tracked medical countermeasure development. Here, we show that transgenic mice expressing the human SARS-CoV-2 receptor (angiotensin-converting enzyme 2 [hACE2]) under a cytokeratin 18 promoter (K18) are susceptible to SARS-CoV-2 and that infection resulted in a dose-dependent lethal disease course. After inoculation with either 104 TCID50 or 105 TCID50, the SARS-CoV-2 infection resulted in rapid weight loss in both groups and uniform lethality in the 105 TCID50 group. High levels of viral RNA shedding were observed from the upper and lower respiratory tract and intermittent shedding was observed from the intestinal tract. Inoculation with SARS-CoV-2 resulted in upper and lower respiratory tract infection with high infectious virus titers in nasal turbinates, trachea and lungs. The observed interstitial pneumonia and pulmonary pathology, with SARS-CoV-2 replication evident in pneumocytes, were similar to that reported in severe cases of COVID-19. SARS-CoV-2 infection resulted in macrophage and lymphocyte infiltration in the lungs and upregulation of Th1 and proinflammatory cytokines/chemokines. Extrapulmonary replication of SARS-CoV-2 was observed in the cerebral cortex and hippocampus of several animals at 7 DPI but not at 3 DPI. The rapid inflammatory response and observed pathology bears resemblance to COVID-19. Additionally, we demonstrate that a mild disease course can be simulated by low dose infection with 102 TCID50 SARS-CoV-2, resulting in minimal clinical manifestation and near uniform survival. Taken together, these data support future application of this model to studies of pathogenesis and medical countermeasure development.

A single dose of ChAdOx1 MERS provides protective immunity in rhesus macaques.

Developing a vaccine to protect against the lethal effects of the many strains of coronavirus is critical given the current global pandemic. For Middle East respiratory syndrome coronavirus (MERS-CoV), we show that rhesus macaques seroconverted rapidly after a single intramuscular vaccination with ChAdOx1 MERS. The vaccine protected against respiratory injury and pneumonia and reduced viral load in lung tissue by several orders of magnitude. MERS-CoV replication in type I and II pneumocytes of ChAdOx1 MERS-vaccinated animals was absent. A prime-boost regimen of ChAdOx1 MERS boosted antibody titers, and viral replication was completely absent from the respiratory tract tissue of these rhesus macaques. We also found that antibodies elicited by ChAdOx1 MERS in rhesus macaques neutralized six different MERS-CoV strains. Transgenic human dipeptidyl peptidase 4 mice vaccinated with ChAdOx1 MERS were completely protected against disease and lethality for all different MERS-CoV strains. The data support further clinical development of ChAdOx1 MERS.

Protective efficacy of a novel simian adenovirus vaccine against lethal MERS-CoV challenge in a transgenic human DPP4 mouse model.

Middle East respiratory syndrome coronavirus (MERS-CoV) is a novel zoonotic virus that causes severe respiratory disease in humans with a case fatality rate close to 40%, but for which no vaccines are available. Here, we evaluated the utility of ChAdOx1, a promising replication-deficient simian adenovirus vaccine vector platform with an established safety profile in humans and dromedary camels, for MERS-CoV vaccine development. Using a transgenic lethal BALB/c MERS-CoV mouse model we showed that single dose intranasal or intramuscular immunisation with ChAdOx1 MERS, encoding full-length MERS-CoV Spike glycoprotein, is highly immunogenic and confers protection against lethal viral challenge. Immunogenicity and efficacy were comparable between immunisation routes. Together these data provide support for further evaluation of ChAdOx1 MERS vaccine in humans and dromedary camels, the animal reservoir of infection.

Malignant peripheral nerve sheath tumor with glandular differentiation in a patient with neurofibromatosis type 1.

: The authors report an unusual case of malignant peripheral nerve sheath tumor with malignant differentiation arising as a subcutaneous nodule in the thigh of a 53-year-old woman with a history significant for neurofibromatosis type 1. Peripheral nerve sheath tumors containing a glandular component, commonly referred to as glandular peripheral nerve sheath tumors, are rare neoplasms found largely in patients with neurofibromatosis type 1. These tumors are frequently malignant; recognition of metastatic potential is made based on the atypical spindle-cell component. Rarely, as in our case, the glandular component is also histologically malignant. Only 5 such tumors have been described in the literature to date. Glandular differentiation, particularly with malignant features, can be a potentially misleading feature when found as a component of malignant peripheral nerve sheath tumors and raise a wide spectrum of differential diagnoses, including metastatic Sertoli-Leydig tumors. The patient is free of disease for 22 months after wide tumor reexcision, which contrasts with previously reported devastatingly poor prognosis of these tumors.

Symptomatic cesarean scar diverticulum: a case report.

BACKGROUND: Extrauterine lesions of intermediate trophoblast have occurred in and around fallopian tubes and ovaries and are thought to result from an exaggerated trophoblastic response to the implantation site of a previous ectopic pregnancy. Additionally, cesarean scar defects have recently been identified as a source of persistent, irregular vaginal bleeding in women and can be identified by pelvic ultrasound. CASE: A 35-year-old woman presented with irregular vaginal bleeding in association with an anterior extrauterine cystic mass detected by pelvic ultrasound and thought to represent a cesarean scar defect. Subsequent histology revealed an endometrial diverticulum lined with chorionic-type intermediate trophoblast, a subpopulation of trophoblast that composes placental site nodules. CONCLUSION: This was the first case of a lesion of intermediate trophoblast occurring in a cesarean scar diverticulum.