Coronavirus in Cats SARS-CoV-2 was detected in three cats after they were cohoused with cats that had been experimentally inoculated with the virus. Cats may be a silent intermediate host of SARS-C...
BackgroundTo develop an effective vaccine against a novel viral pathogen, it is important to understand the longitudinal antibody responses against its first infection. Here we performed a longitudinal study of antibody responses against SARS-CoV-2 in symptomatic patients.MethodsSequential blood samples were collected from 39 individuals at various timepoints between 0 and 154 days after onset. IgG or IgM titers to the receptor binding domain (RBD) of the S protein, the ectodomain of the S protein, and the N protein were determined by using an ELISA. Neutralizing antibody titers were measured by using a plaque reduction assay.FindingsThe IgG titers to the RBD of the S protein, the ectodomain of the S protein, and the N protein peaked at about 20 days after onset, gradually decreased thereafter, and were maintained for several months after onset. Extrapolation modeling analysis suggested that the IgG antibodies were maintained for this amount of time because the rate of reduction slowed after 30 days post-onset. IgM titers to the RBD decreased rapidly and disappeared in some individuals after 90 days post-onset. All patients, except one, possessed neutralizing antibodies against authentic SARS-CoV-2, which they retained at 90 days after onset. The highest antibody titers in patients with severe infections were higher than those in patients with mild or moderate infections, but the decrease in antibody titer in the severe infection cohort was more remarkable than that in the mild or moderate infection cohort.InterpretationAlthough the number of patients is limited, our results show that the antibody response against the first SARS-CoV-2 infection in symptomatic patients is typical of that observed in an acute viral infection.FundingThe Japan Agency for Medical Research and Development and the National Institutes of Allergy and Infectious Diseases.
Antiretroviral therapy for HIV-1 infection/AIDS has significantly extended the life expectancy of HIV-1-infected individuals and reduced HIV-1 transmission at very high rates. However, certain individuals who initially achieve viral suppression to undetectable levels may eventually suffer treatment failure mainly due to adverse effects and the emergence of drug-resistant HIV-1 variants. Here, we report GRL-142, a novel HIV-1 protease inhibitor containing an unprecedented 6-5-5-ring-fused crown-like tetrahydropyranofuran, which has extremely potent activity against all HIV-1 strains examined with IC50 values of attomolar-to-picomolar concentrations, virtually no effects on cellular growth, extremely high genetic barrier against the emergence of drug-resistant variants, and favorable intracellular and central nervous system penetration. GRL-142 forms optimum polar, van der Waals, and halogen bond interactions with HIV-1 protease and strongly blocks protease dimerization, demonstrating that combined multiple optimizing elements significantly enhance molecular and atomic interactions with a target protein and generate unprecedentedly potent and practically favorable agents.
ABSTRACT We identified four novel nonpeptidic human immunodeficiency virus type 1 (HIV-1) protease inhibitors (PIs), GRL-078, -079, -077, and -058, containing an alkylamine at the C-5 position of P2 tetrahydropyrano-tetrahydrofuran (Tp-THF) and a P2′ cyclopropyl (Cp) (or isopropyl)-aminobenzothiazole (Abt) moiety. Their 50% effective concentrations (EC 50 s) were 2.5 to 30 nM against wild-type HIV-1 NL4-3 , 0.3 to 6.7 nM against HIV-2 EHO , and 0.9 to 90 nM against laboratory-selected PI-resistant HIV-1 and clinical HIV-1 variants resistant to multiple FDA-approved PIs (HIV MDR ). GRL-078, -079, -077, and -058 also effectively blocked the replication of HIV-1 variants highly resistant to darunavir (DRV) (HIV DRV r p51 ), with EC 50 s of 38, 62, 61, and 90 nM, respectively, while four FDA-approved PIs examined (amprenavir, atazanavir, lopinavir [LPV], and DRV) had virtually no activity (EC 50 s of >1,000 nM) against HIV DRV r p51 . Structurally, GRL-078, -079, and -058 form strong hydrogen bond interactions between Tp-THF modified at C-5 and Asp29/Asp30/Gly48 of wild-type protease, while the P2′ Cp-Abt group forms strong hydrogen bonds with Asp30′. The Tp-THF and Cp-Abt moieties also have good nonpolar interactions with protease residues located in the flap region. For selection with LPV and DRV by use of a mixture of 11 HIV MDR strains (HIV 11MIX ), HIV 11MIX became highly resistant to LPV and DRV over 13 to 32 and 32 to 41 weeks, respectively. However, for selection with GRL-079 and GRL-058, HIV 11MIX failed to replicate at >0.08 μM and >0.2 μM, respectively. Thermal stability results supported the highly favorable anti-HIV-1 potency of GRL-079 as well as other PIs. The present data strongly suggest that the P2 Tp-THF group modified at C-5 and the P2′ Abt group contribute to the potent anti-HIV-1 profiles of the four PIs against HIV-1 NL4-3 and a wide spectrum of HIV MDR strains.
Reverse transcription-quantitative PCR (RT-qPCR)-based tests are widely used to diagnose coronavirus disease 2019 (COVID-19). As a result that these tests cannot be done in local clinics where RT-qPCR testing capability is lacking, rapid antigen tests (RATs) for COVID-19 based on lateral flow immunoassays are used for rapid diagnosis. However, their sensitivity compared with each other and with RT-qPCR and infectious virus isolation has not been examined. Here, we compared the sensitivity among four RATs by using severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) isolates and several types of COVID-19 patient specimens and compared their sensitivity with that of RT-qPCR and infectious virus isolation. Although the RATs read the samples containing large amounts of virus as positive, even the most sensitive RAT read the samples containing small amounts of virus as negative. Moreover, all RATs tested failed to detect viral antigens in several specimens from which the virus was isolated. The current RATs will likely miss some COVID-19 patients who are shedding infectious SARS-CoV-2.
Significance Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants are of concern, with the P.1 variants dominating in Brazil. Brazil is now seeing a record number of deaths. Here, we report that the pathogenicity in hamsters of a P.1 variant is similar to that of nonvariant SARS-CoV-2. However, it has an expanded host range as shown by its replication in mice. Prior infection with nonvariant SARS-CoV-2 strains efficiently prevented replication of the P.1 variant in the lower respiratory tract of hamsters upon reinfection. Convalescent sera from patients infected with nonvariants or sera from messenger RNA vaccinees showed comparable neutralization titers among the P.1 and previously circulating strains. These results suggest that previous SARS-CoV-2 infection and vaccines based on the original SARS-CoV-2 will provide some protection against P.1 infection.
