A newly described coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is the causative agent of coronavirus disease 2019 (COVID-19), has infected over 2.3 million people, led to the death of more than 160,000 individuals and caused worldwide social and economic disruption1,2. There are no antiviral drugs with proven clinical efficacy for the treatment of COVID-19, nor are there any vaccines that prevent infection with SARS-CoV-2, and efforts to develop drugs and vaccines are hampered by the limited knowledge of the molecular details of how SARS-CoV-2 infects cells. Here we cloned, tagged and expressed 26 of the 29 SARS-CoV-2 proteins in human cells and identified the human proteins that physically associated with each of the SARS-CoV-2 proteins using affinity-purification mass spectrometry, identifying 332 high-confidence protein–protein interactions between SARS-CoV-2 and human proteins. Among these, we identify 66 druggable human proteins or host factors targeted by 69 compounds (of which, 29 drugs are approved by the US Food and Drug Administration, 12 are in clinical trials and 28 are preclinical compounds). We screened a subset of these in multiple viral assays and found two sets of pharmacological agents that displayed antiviral activity: inhibitors of mRNA translation and predicted regulators of the sigma-1 and sigma-2 receptors. Further studies of these host-factor-targeting agents, including their combination with drugs that directly target viral enzymes, could lead to a therapeutic regimen to treat COVID-19. A human–SARS-CoV-2 protein interaction map highlights cellular processes that are hijacked by the virus and that can be targeted by existing drugs, including inhibitors of mRNA translation and predicted regulators of the sigma receptors.

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A SARS-CoV-2 protein interaction map reveals targets for drug repurposing.

A Manual of Methods for Baculovirus Vectors and Insect Cell Culture Procedures.

A streptomycete was isolated from an Easter Island soil sample and found to inhibit Candida albicans, Microsporum gypseum and Trichophyton granulosum. The antibiotic-producing microorganism was characterized and identified as Streptomyces hygroscopicus. The antifungal principle was extracted with organic solvent from the mycelium, isolated in crystalline form and named rapamycin. Rapamycin is mainly active against Candida albicans; minimum inhibitory concentration against ten strains ranged from 0.02 to 0.2 mug/ml. Its apparent activity against Microsporum gypseum and Trichophyton granulosum is lower because of its instability in culture media on prolonged incubation required by these fungi. No activity was observed against gram-positive and gram-negative bacteria. Acute toxicity in mice is low.

Rapamycin (ay-22, 989), a new antifungal antibiotic i. taxonomy of the producing streptomycete and isolation of the active principle

A real-time reverse transcriptase PCR (RRT-PCR) assay based on the avian influenza virus matrix gene was developed for the rapid detection of type A influenza virus. Additionally, H5 and H7 hemagglutinin subtype-specific probe sets were developed based on North American avian influenza virus sequences. The RRT-PCR assay utilizes a one-step RT-PCR protocol and fluorogenic hydrolysis type probes. The matrix gene RRT-PCR assay has a detection limit of 10 fg or approximately 1,000 copies of target RNA and can detect 0.1 50% egg infective dose of virus. The H5- and H7-specific probe sets each have a detection limit of 100 fg of target RNA or approximately 103 to 104 gene copies. The sensitivity and specificity of the real-time PCR assay were directly compared with those of the current standard for detection of influenza virus: virus isolation (VI) in embryonated chicken eggs and hemagglutinin subtyping by hemagglutination inhibition (HI) assay. The comparison was performed with 1,550 tracheal and cloacal swabs from various avian species and environmental swabs obtained from live-bird markets in New York and New Jersey. Influenza virus-specific RRT-PCR results correlated with VI results for 89% of the samples. The remaining samples were positive with only one detection method. Overall the sensitivity and specificity of the H7- and H5-specific RRT-PCR were similar to those of VI and HI.

Development of a Real-Time Reverse Transcriptase PCR Assay for Type A Influenza Virus and the Avian H5 and H7 Hemagglutinin Subtypes

The mouse was found to be natively susceptible to Listeria monocytogenes . Its susceptibility was attributed to the capacity of the organism to survive and multiplying in host macrophages. During the first 3 days of a primary infection the bacterial populations of spleen and liver were found to increase at a constant rate. On the 4th day of infection the host became hypersensitive to Listeria antigens and at the same time bacterial growth ceased. A rapid inactivation of the organism ensued.

Convalescent mice were resistant to challenge, but no protective factor could be found in their serum. Histological evidence suggested that acquired resistance was the result of a change occurring in the host's mononuclear phagocytes. When challenged in vitro , the macrophages of convalescent mice were found to resist infection with Listeria monocytogenes. Listeria -resistant cells appeared during the course of infection at a time which corresponded with the development of the antibacterial mechanism in the spleen. They persisted for as long as the antibacterial mechanism remained intact in this organ.

This period of absolute resistance to Listeria lasted about 3 weeks. Thereafter, the host remained hypersensitive but unable to inactivate a challenge inoculum of Listeria . However, it remained capable of producing an accelerated response to reinfection. This was thought to depend upon an ability to generate a new population of resistant cells from a residuum of specifically sensitized macrophages or macrophage precursors still surviving in the tissues as a result of the immunological activation which occurred during the primary infection.

https://rupress.org/jem/article-pdf/116/3/381/1391655/381.pdf

H. Muench

Papers

A simple method of estimating fifty per cent endpoints