Experimentelle Kaninchensyphilis und das Reticuloendothelialsystem

Bei experimenteller Kaninchensyphilis fuhrte der Verfasser seine Versuche aus, berucksichtigt auf die klinischen Befunde und die Wassermannsche Reaktion des mit Sp. pallida geimpften Kaninchens bei der Splenektomie, bei der Blockierung des Reticuloendothelialsystemes und bei der Einspritzung des Milzextractes. Die Resultate sind die folgenden: 1. Nachdem Spirochaeta pallida dem Kaninchen in den Hoden geimpft wurde, wurde die Blockierung mit Tusche ausgefuhrt. Im Verlaufe der Infektion zeigten sich lokale Befunde und Wassermannsche Reaktion die in jeder Hinsicht denen der Kontrollen glichen. 2. Beim Kaninchen, welches gleichzeizig entmilzt und mit Sp. pallida geimpft wurde, trat der Lokalaffekt etwas fruhzeizig auf und die Wassermannsche Reaktion war kurzdauernd positiv. 3. Falls die Impfung nach der Entmilzung ausgefuhrt war, stimmten die Resultate fast mit den obigen ein. 4. Wenn die Versuchstiere erst geimpft und dann entmilzt wurden, so wurde eine bemerkenswerte oedematose Anschwellung des Hodensacks und ein Kurzdauernder positive Ausfall der Wa. R. beobachtet. 5. Wenn die Entmilzung, Impfung und Blockierung gleichzeizig ausgefuhrt wurden, so zeigten sich die lokalen sowie metastatischen Befunde bei Versuchstieren wie ohne Entmilzung, doch war die positive Phase der Wa. R. bedeutend verkurzt und dabei ihre Grad niederwertig. 6. Erst geimpft und dann mit Milzextract wiederhohlt gespritzt, so verliefen die lokalen sowie metastatischen Befunde leichter und die Wa. R. brach fruhzeizig positiv aus und dauerte langer. (Autoreferat.

Safety, pharmacodynamics, and antiviral activity of selgantolimod in viremic patients with chronic hepatitis B virus infection

Background &amp; Aims: Novel finite therapies for chronic hepatitis B (CHB) are needed, since lifelong treatment is usually required with current available oral antivirals. This phase II study (NCT03615066) evaluated the safety, pharmacodynamics, and antiviral activity of selgantolimod (a Toll-like receptor 8 agonist [TLR8]) with tenofovir alafenamide (TAF). Methods: Viremic patients with CHB not receiving treatment were stratified by HBeAg status and randomized 2:2:1 to TAF 25 mg/day with selgantolimod 3 mg orally once weekly (QW), selgantolimod 1.5 mg QW, or placebo. Combination therapy continued until week (W)24, followed by TAF monotherapy until W48; patients then discontinued TAF and were followed until W96 (treatment-free follow-up [TFFU] period). The primary efficacy endpoint was the proportion with ≥1 log10 IU/ml HBsAg decline at W24. Results: Sixty-seven patients received study drug; 27 were followed during TFFU. Nausea, headache, vomiting, fatigue, and dizziness were the most common adverse events. Most adverse events were grade 1. Alanine aminotransferase flares were not observed up to W48. Four patients experienced alanine aminotransferase and hepatitis flares during TFFU; all had HBV DNA increases. Selgantolimod increased serum cytokines and chemokines and redistributed several circulating immune cell subsets. No patients achieved the primary efficacy endpoint. Mean HBsAg changes were −0.12, −0.16, and −0.12 log10 IU/ml in the selgantolimod 3 mg, selgantolimod 1.5 mg, and placebo groups, respectively, at W48; HBV DNA declined in all groups by ≥2 log10 IU/ml as early as W2, with all groups rebounding to baseline during TFFU. No HBsAg or HBeAg loss or seroconversion was observed throughout TFFU. Conclusions: Selgantolimod up to 3 mg was safe and well tolerated. Pharmacodynamics and antiviral activity in viremic patients support continued study of selgantolimod in combination CHB therapies. Impact and implications: Novel therapeutics for chronic HBV infection are needed to achieve a functional cure. In this study, we confirmed the safety and tolerability of selgantolimod (formerly GS-9688, a TLR8) when administered with tenofovir alafenamide over 24 weeks in viremic patients with chronic HBV infection. Overall, declines in HBsAg levels with selgantolimod treatment were modest; subgroup analysis indicated that patients with alanine aminotransferase levels greater than the upper limit of normal had significantly greater declines compared to those with normal alanine aminotransferase levels (–0.20 vs. –0.03 log10 IU/ml; p &lt;0.001). These findings suggest a potential differential response to selgantolimod based on patients’ baseline HBV-specific immune response, which should be considered in future investigations characterizing the underlying mechanisms of selgantolimod treatment and in HBV cure studies using similar immunomodulatory pathways. Clinical trial number: NCT03615066 be found at https://www.gileadclinicaltrials.com/transparency-policy/.</p

Safety, pharmacodynamics, and antiviral activity of selgantolimod in viremic patients with chronic hepatitis B virus infection

Background &amp; Aims: Novel finite therapies for chronic hepatitis B (CHB) are needed, since lifelong treatment is usually required with current available oral antivirals. This phase II study (NCT03615066) evaluated the safety, pharmacodynamics, and antiviral activity of selgantolimod (a Toll-like receptor 8 agonist [TLR8]) with tenofovir alafenamide (TAF). Methods: Viremic patients with CHB not receiving treatment were stratified by HBeAg status and randomized 2:2:1 to TAF 25 mg/day with selgantolimod 3 mg orally once weekly (QW), selgantolimod 1.5 mg QW, or placebo. Combination therapy continued until week (W)24, followed by TAF monotherapy until W48; patients then discontinued TAF and were followed until W96 (treatment-free follow-up [TFFU] period). The primary efficacy endpoint was the proportion with ≥1 log10 IU/ml HBsAg decline at W24. Results: Sixty-seven patients received study drug; 27 were followed during TFFU. Nausea, headache, vomiting, fatigue, and dizziness were the most common adverse events. Most adverse events were grade 1. Alanine aminotransferase flares were not observed up to W48. Four patients experienced alanine aminotransferase and hepatitis flares during TFFU; all had HBV DNA increases. Selgantolimod increased serum cytokines and chemokines and redistributed several circulating immune cell subsets. No patients achieved the primary efficacy endpoint. Mean HBsAg changes were −0.12, −0.16, and −0.12 log10 IU/ml in the selgantolimod 3 mg, selgantolimod 1.5 mg, and placebo groups, respectively, at W48; HBV DNA declined in all groups by ≥2 log10 IU/ml as early as W2, with all groups rebounding to baseline during TFFU. No HBsAg or HBeAg loss or seroconversion was observed throughout TFFU. Conclusions: Selgantolimod up to 3 mg was safe and well tolerated. Pharmacodynamics and antiviral activity in viremic patients support continued study of selgantolimod in combination CHB therapies. Impact and implications: Novel therapeutics for chronic HBV infection are needed to achieve a functional cure. In this study, we confirmed the safety and tolerability of selgantolimod (formerly GS-9688, a TLR8) when administered with tenofovir alafenamide over 24 weeks in viremic patients with chronic HBV infection. Overall, declines in HBsAg levels with selgantolimod treatment were modest; subgroup analysis indicated that patients with alanine aminotransferase levels greater than the upper limit of normal had significantly greater declines compared to those with normal alanine aminotransferase levels (–0.20 vs. –0.03 log10 IU/ml; p &lt;0.001). These findings suggest a potential differential response to selgantolimod based on patients’ baseline HBV-specific immune response, which should be considered in future investigations characterizing the underlying mechanisms of selgantolimod treatment and in HBV cure studies using similar immunomodulatory pathways. Clinical trial number: NCT03615066 be found at https://www.gileadclinicaltrials.com/transparency-policy/.</p

Remdesivir for 5 or 10 Days in Patients With Severe Covid-19

Background: Remdesivir is an RNA polymerase inhibitor with potent antiviral activity in vitro and efficacy in animal models of coronavirus disease 2019 (Covid-19). Methods: We conducted a randomized, open-label, phase 3 trial involving hospitalized patients with confirmed SARS-CoV-2 infection, oxygen saturation of 94% or less while they were breathing ambient air, and radiologic evidence of pneumonia. Patients were randomly assigned in a 1:1 ratio to receive intravenous remdesivir for either 5 days or 10 days. All patients received 200 mg of remdesivir on day 1 and 100 mg once daily on subsequent days. The primary end point was clinical status on day 14, assessed on a 7-point ordinal scale. Results: In total, 397 patients underwent randomization and began treatment (200 patients for 5 days and 197 for 10 days). The median duration of treatment was 5 days (interquartile range, 5 to 5) in the 5-day group and 9 days (interquartile range, 5 to 10) in the 10-day group. At baseline, patients randomly assigned to the 10-day group had significantly worse clinical status than those assigned to the 5-day group (P = 0.02). By day 14, a clinical improvement of 2 points or more on the ordinal scale occurred in 64% of patients in the 5-day group and in 54% in the 10-day group. After adjustment for baseline clinical status, patients in the 10-day group had a distribution in clinical status at day 14 that was similar to that among patients in the 5-day group (P = 0.14). The most common adverse events were nausea (9% of patients), worsening respiratory failure (8%), elevated alanine aminotransferase level (7%), and constipation (7%). Conclusions: In patients with severe Covid-19 not requiring mechanical ventilation, our trial did not show a significant difference between a 5-day course and a 10-day course of remdesivir. With no placebo control, however, the magnitude of benefit cannot be determined. (Funded by Gilead Sciences; GS-US-540-5773 ClinicalTrials.gov number, NCT04292899.)

IDDF2020-ABS-0060 Impact of prior tenofovir disoproxil fumarate (TDF) treatment duration on tenofovir alafenamide (TAF) safety profile in virally suppressed chronic HBV patients switched from TDF to TAF

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Adenovirus Binding to Blood Factors Results in Liver Cell Infection and Hepatotoxicity

Adenoviruses (Ad) are efficient vehicles for gene delivery in vitro and in vivo. Therefore, they are a promising tool in gene therapy, particularly in the treatment of cancer and cardiovascular diseases. However, preclinical and clinical studies undertaken during the last decade have revealed a series of problems that limit both the safety and efficacy of Ad vectors, specifically after intravenous application. Major obstacles to clinical use include innate toxicity and Ad sequestration by nontarget tissues. The factors and mechanisms underlying these processes are poorly understood. The majority of intravenously injected Ad particles are sequestered by the liver, which in turn causes an inflammatory response characterized by acute transaminitis and vascular damage. Here, we describe a novel pathway that is used by Ad for infection of hepatocytes and Kupffer cells upon intravenous virus application in mice. We found that blood factors play a major role in targeting Ad vectors to hepatic cells. We demonstrated that coagulation factor IX and complement component C4-binding protein can bind the Ad fiber knob domain and provide a bridge for virus uptake through cell surface heparan sulfate proteoglycans and low-density lipoprotein receptor-related protein. An Ad vector, Ad5mut, which contained mutations in the fiber knob domain ablating blood factor binding, demonstrated significantly reduced infection of liver cells and liver toxicity in vivo. This study contributes to a better understanding of adenovirus-host interactions for intravenously applied vectors. It also provides a rationale for novel strategies to target adenovirus vector to specific tissues and to reduce virus-associated toxicity after systemic application

Localization of Regions in CD46 That Interact with Adenovirus

A variety of pathogens use CD46, a ubiquitously expressed membrane protein that regulates complement activation, as a cellular attachment receptor. While the CD46 binding sites of several pathogens, including measles virus, Neisseria gonorrhea, and human herpesvirus 6, have been described, the region of CD46 responsible for adenovirus binding has not been determined. In this study, we used competition experiments with known CD46 ligands, CD46-specific antibodies, and a set of CD46 mutants to localize the binding domain for the group B adenovirus serotype 35 (Ad35). Our results show that Ad35 competes with measles virus for binding to CD46 but not with complement protein C3b. We further show that this interaction is a protein-protein interaction and that N glycosylations do not critically contribute to infection with Ad35 fiber-containing Ad vectors. Our data demonstrate that the native conformation of the CCP2 domain is crucial for Ad35 binding and that the substitution of amino acids at positions 130 to 135 or 152 to 156 completely abolishes the receptor function of CD46. These regions localize to the same planar face of CD46 and likely form an extended adenovirus binding surface, since no single amino acid substitution within these areas eliminates virus binding. Finally, we demonstrate that the infection with a virus possessing human group B serotype Ad11 fibers is also mediated by the CCP2 domain. This information is important to better characterize the mechanisms of the receptor recognition by adenovirus relative to other pathogens that interact with CD46, and it may help in the design of antiviral therapeutics against adenovirus serotypes that use CD46 as a primary cellular attachment receptor

The Interaction between the Fiber Knob Domain and the Cellular Attachment Receptor Determines the Intracellular Trafficking Route of Adenoviruses

Most of the presently used adenovirus (Ad) vectors are based on serotype 5. However, the application of these vectors is limited by the native tropism of Ad5. To address this problem, a series of fiber chimeric vectors were produced to take advantage of the different cellular receptors used by Ad of different subgroups. In this study we utilize an Ad5-based chimeric vector containing sequences encoding the Ad35 fiber knob domain instead of the Ad5 knob (Ad5/35L) to analyze factors responsible for selection of intracellular trafficking routes by Ads. By competition analysis with recombinant Ad5 and Ad35 knobs we showed that the Ad5/35L vector infected cells through a receptor different from the Ad5 receptor. Intracellular trafficking of Ad5 and Ad5/35L viruses was analyzed in HeLa cells by tracking fluorophore-conjugated Ad particles, by immunostaining for capsid hexon protein, by electron microscopy, and by Southern blotting for viral DNA. These studies showed that the interaction with the Ad35 receptor(s) predestines Ad5/35L vector to intracellular trafficking pathways different from those of Ad5. Ad5 efficiently escaped from the endosomes early after infection. In contrast, Ad5/35L remained longer in late endosomal/lysosomal compartments and used them to achieve localization to the nucleus. However, a significant portion of Ad5/35L particles appeared to be recycled back to the cell surface. This phenomenon resulted in significantly less efficient Ad5/35L-mediated gene transfer compared to that of Ad5. We also demonstrated that the selection of intracellular trafficking routes was determined by the fiber knob domain and did not depend on the length of the fiber shaft. This study contributes to a better understanding of the mechanisms that govern the infection of retargeted, capsid-modified vectors which have potential application for hematopoietic stem cell and tumor gene therapy