One or two injections of MVA-vectored vaccine shields hACE2 transgenic mice from SARS-CoV-2 upper and lower respiratory tract infection

Modified vaccinia virus Ankara (MVA) is a replication-restricted smallpox vaccine, and numerous clinical studies of recombinant MVAs (rMVAs) as vectors for prevention of other infectious diseases, including COVID-19, are in progress. Here, we characterize rMVAs expressing the S protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Modifications of full-length S individually or in combination included two proline substitutions, mutations of the furin recognition site, and deletion of the endoplasmic retrieval signal. Another rMVA in which the receptor binding domain (RBD) is flanked by the signal peptide and transmembrane domains of S was also constructed. Each modified S protein was displayed on the surface of rMVA-infected cells and was recognized by anti-RBD antibody and soluble hACE2 receptor. Intramuscular injection of mice with the rMVAs induced antibodies, which neutralized a pseudovirus in vitro and, upon passive transfer, protected hACE2 transgenic mice from lethal infection with SARS-CoV-2, as well as S-specific CD3+CD8+IFNγ+ T cells. Antibody boosting occurred following a second rMVA or adjuvanted purified RBD protein. Immunity conferred by a single vaccination of hACE2 mice prevented morbidity and weight loss upon intranasal infection with SARS-CoV-2 3 wk or 7 wk later. One or two rMVA vaccinations also prevented detection of infectious SARS-CoV-2 and subgenomic viral mRNAs in the lungs and greatly reduced induction of cytokine and chemokine mRNAs. A low amount of virus was found in the nasal turbinates of only one of eight rMVA-vaccinated mice on day 2 and none later. Detection of low levels of subgenomic mRNAs in turbinates indicated that replication was aborted in immunized animals.

Recombinant DNA methods have revolutionized the engineering of vaccines against microbial pathogens, thereby creating opportunities to control the current COVID-19 pandemic (1). The main categories of recombinant vaccines are protein, nucleic acid (DNA and RNA), virus vectors (replicating and nonreplicating), and genetically modified live viruses. Each approach has advantages and drawbacks with regard to manufacture, stability, cold-chain requirements, mode of inoculation, and immune stimulation. Recombinant proteins have been successfully deployed as vaccines against a variety of diseases (2–5). DNA vaccines have been licensed for veterinary purposes (6, 7), although none are in regular human use. Recently developed messenger RNA (mRNA) vaccines are in use for COVID-19 and are in preclinical development for other infectious diseases (8). At least 12 virus vector vaccines based on adenovirus, fowlpox virus, vaccinia virus (VACV), and yellow fever virus have veterinary applications, but, so far, only two have been marketed for humans (9), although numerous clinical trials, particularly with attenuated adenovirus and VACV, are listed online in ClinicalTrials.gov.A variety of recombinant approaches utilizing the spike (S) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2; abbreviated CoV-2) as immunogen are being explored to quell the COVID-19 pandemic (10). Vaccines based on mRNA and adenovirus vectors have demonstrated promising results in clinical trials and have received emergency regulatory approval (11–14). Other candidate CoV-2 vaccines, including ones based on vesicular stomatitis virus (15), an alphavirus-derived replicon RNA (16), an inactivated recombinant Newcastle Disease virus (17), and modified VACV Ankara (MVA) (18, 19) are at early stages of evaluation.Experiments with virus vectors for vaccination were carried out initially with VACV (20, 21), providing a precedent for a multitude of other virus vectors (9). The majority of current VACV vaccine studies employ the MVA strain, which was attenuated by more than 500 passages in chicken embryo fibroblasts during which numerous genes were deleted or mutated, resulting in an inability to replicate in human and most other mammalian cells (22). Despite the inability to complete a productive infection, MVA is capable of highly expressing recombinant genes and inducing immune responses (23, 24). MVA is a licensed smallpox vaccine, and numerous clinical studies of recombinant MVA (rMVA) vectors are in progress or have been completed. Protection has been obtained with MVA-based SARS-CoV-1 and Middle East respiratory syndrome CoV (MERS-CoV) in animals (25–28), and an MVA-based MERS-CoV vaccine was shown to be safe and immunogenic in a phase 1 clinical trial (29). Currently, two clinical trials for MVA-based CoV-2 vaccines are in the recruiting phase (ClinicalTrials.gov). Here, we show that one or two immunizations with rMVAs expressing the CoV-2 S proteins elicit strong neutralizing antibody responses, induce CD8+ T cells, and protect susceptible transgenic mice against a lethal intranasal challenge with CoV-2 virus, supporting clinical testing of related rMVA vaccines.     

Bleeding diathesis in amyloidosis with renal insufficiency associated with Crohn''s disease: response to desmopressin

A 53-yr-old man with a 33-yr history of Crohn's ileocolitis, complicated by arthritis and cologastric fistulization, was diagnosed with GI amyloidosis at the time of proctocolectomy. He had marked proteinuria (4.2 g/24 h) and moderate renal insufficiency (BUN of 35 mg/dl and serum creatinine of 2.5 mg/dl). During the operation, he had severe bleeding that required 11 U of blood. Postoperatively, desmopressin was administered, which resulted in a prompt cessation of bleeding. This case demonstrates the efficacy of desmopressin in reversing the bleeding diathesis in surgical patients with amyloidosis complicated by renal insufficiency.     

Tattoo of colonic neoplasms in 113 patients with a new sterile carbon compound

BACKGROUND: Endoscopic marking of intestinal lesions is essential when difficulty is anticipated with subsequent localization during surgical resection or postpolypectomy surveillance. The most commonly used indelible marker has been India ink, which must be diluted and sterilized, a cumbersome process. SPOT, a prepackaged, sterile Food and Drug Administration-approved formulation of pure carbon particles in suspension, eliminates the need for preinjection preparation. METHODS: Ten patients with colonic polyps deemed endoscopically unresectable or malignant-appearing had the area surrounding the lesions injected with SPOT and subsequently underwent surgical resection. An additional 103 patients underwent colonoscopic injection with SPOT and were followed endoscopically or underwent surgery at another hospital. RESULTS: The SPOT injection sites were visible to the surgeons in all 10 cases. On histopathologic evaluation, none of the resection specimens exhibited necrosis or abscess formation. In total, there were 118 SPOT injections in 113 patients; none had fever, abdominal pain, or any other signs or symptoms of inflammation develop. In the nonoperated group, 42 patients subsequently underwent colonoscopies at our institution, and in all cases stains were readily identifiable at the injection sites. CONCLUSIONS: SPOT is a safe and effective marker for use at colonoscopy when surgical resection is anticipated. It is also useful for endoscopic follow-up of patients who have not undergone surgery.     

Resolution of Protein-losing Hypertrophic Lymphocytic Gastritis with Therapeutic Eradication of Helicobacter pylori

Lymphocytic gastritis (LG) is a recently described histological entity characterized by increased lymphocytes in the superficial gastric epithelium and foveolae. It includes a subgroup of patients with giant gastric folds and, often, a protein-losing state, a condition termed hypertrophic lymphocytic gastritis (HLG). Despite close endoscopic and clinical similarities to classical Menetrier's disease, the histopathological features of these two diseases are sufficiently distinct that they are regarded as separate entities. The etiology and pathogenesis of HLG are unknown, and the possible etiological role of Helieobaeter pytori in particular is controversial. For this reason we report the case of a 48-yr-old female with HLG, hypoproteinemia, and H. pylori infection whose disease resolved clinically, endoscopically, and pathologically with therapeutic eradication of the H. pylori. H. pylori infection may be a treatable cause of at least some cases of HLG and should therefore be carefully sought in any patient with this condition.     

Changes in abdominal wall thickness during laparoscopy: implications for the use of magnetic assisted surgery

Abstract

Introduction: Recently, magnetic solutions have been proposed to minimize surgical invasiveness. These are comprised of deployable instruments containing magnets which are inserted into the abdominal cavity through a single access point. The manipulation of the internal elements occurs via magnets held on the external surface of the abdominal wall. This technology relies on the magnetic force between the magnets, which is inversely related to the abdominal wall thickness (AWT). The aim of this study was to establish the expected change in AWT from before and after initiation of pneumoperitoneum.

Material and methods: Patients scheduled for laparoscopic procedures were assessed by ultrasound for AWT immediately before and during laparoscopy. Change of AWT during laparoscopy was calculated. Statistical analysis was performed using Student’s t-test.

Results: Thirty-two patients undergoing various laparoscopic procedures were included. Twenty patients were male (62.5%) and ten were morbidly obese (31%). Mean age was 51?years (range 18–76) and average BMI was 28.1?kg/m² (range 19.0–41.0). AWT decreased on average by 15.6% once pneumoperitoneum was initiated in both obese and non-obese patients (p?=?.01).

Conclusion: Our data suggest that following preoperative assessment of AWT with abdominal wall ultrasound, more patients than expected might be candidates for the use of trans-abdominal magnetic devices.