RESUMEN
Live-attenuated virus vaccines provide long-lived protection against viral disease but carry inherent risks of residual pathogenicity and genetic reversion. The live-attenuated Candid#1 vaccine was developed to protect Argentines against lethal infection by the Argentine hemorrhagic fever arenavirus, Junín virus. Despite its safety and efficacy in Phase III clinical study, the vaccine is not licensed in the US, in part due to concerns regarding the genetic stability of attenuation. Previous studies had identified a single F427I mutation in the transmembrane domain of the Candid#1 envelope glycoprotein GPC as the key determinant of attenuation, as well as the propensity of this mutation to revert upon passage in cell culture and neonatal mice. To ascertain the consequences of this reversion event, we introduced the I427F mutation into recombinant Candid#1 (I427F rCan) and investigated the effects in two validated small-animal models: in mice expressing the essential virus receptor (human transferrin receptor 1; huTfR1) and in the conventional guinea pig model. We report that I427F rCan displays only modest virulence in huTfR1 mice and appears attenuated in guinea pigs. Reversion at another attenuating locus in Candid#1 GPC (T168A) was also examined, and a similar pattern was observed. By contrast, virus bearing both revertant mutations (A168T+I427F rCan) approached the lethal virulence of the pathogenic Romero strain in huTfR1 mice. Virulence was less extreme in guinea pigs. Our findings suggest that genetic stabilization at both positions is required to minimize the likelihood of reversion to virulence in a second-generation Candid#1 vaccine.IMPORTANCELive-attenuated virus vaccines, such as measles/mumps/rubella and oral poliovirus, provide robust protection against disease but carry with them the risk of genetic reversion to the virulent form. Here, we analyze the genetics of reversion in the live-attenuated Candid#1 vaccine that is used to protect against Argentine hemorrhagic fever, an often-lethal disease caused by the Junín arenavirus. In two validated small-animal models, we find that restoration of virulence in recombinant Candid#1 viruses requires back-mutation at two positions specific to the Candid#1 envelope glycoprotein GPC, at positions 168 and 427. Viruses bearing only a single change showed only modest virulence. We discuss strategies to genetically harden Candid#1 GPC against these two reversion events in order to develop a safer second-generation Candid#1 vaccine virus.
Asunto(s)
Fiebre Hemorrágica Americana , Virus Junin , Vacunas Virales , Animales , Cobayas , Humanos , Ratones , Glicoproteínas/genética , Fiebre Hemorrágica Americana/prevención & control , Virus Junin/fisiología , Pueblos Sudamericanos , Vacunas Atenuadas/genética , Vacunas Virales/genética , VirulenciaRESUMEN
Heartland virus (HRTV) is an emerging tick-borne bandavirus that causes a febrile illness of varying severity in humans, with cases reported in eastern and midwestern regions of the United States. No vaccines or approved therapies are available to prevent or treat HRTV disease. Here, we describe the genetic changes, natural history of disease, and pathogenesis of a mouse-adapted HRTV (MA-HRTV) that is uniformly lethal in 7- to 8-week-old AG129 mice at low challenge doses. We used this model to assess the efficacy of the ribonucleoside analog, 4'-fluorouridine (EIDD-2749), and showed that once-daily oral treatment with 3 mg/kg of drug, initiated after the onset of disease, protects mice against lethal MA-HRTV challenge and reduces viral loads in blood and tissues. Our findings provide insights into HRTV virulence and pathogenesis and support further development of EIDD-2749 as a therapeutic intervention for HRTV disease. IMPORTANCE: More than 60 cases of HRTV disease spanning 14 states have been reported to the United States Centers for Disease Control and Prevention. The expanding range of the Lone Star tick that transmits HRTV, the growing population of at-risk persons living in geographic areas where the tick is abundant, and the lack of antiviral treatments or vaccines raise significant public health concerns. Here, we report the development of a new small-animal model of lethal HRTV disease to gain insight into HRTV pathogenesis and the application of this model for the preclinical development of a promising new antiviral drug candidate, EIDD-2749. Our findings shed light on how the virus causes disease and support the continued development of EIDD-2749 as a therapeutic for severe cases of HRTV infection.
Asunto(s)
Infecciones por Bunyaviridae , Bunyaviridae , Nucleótidos de Uracilo , Animales , Humanos , Ratones , Infecciones por Bunyaviridae/tratamiento farmacológico , Garrapatas , Estados Unidos , Nucleótidos de Uracilo/uso terapéuticoRESUMEN
Rift Valley fever virus (RVFV), an emerging arboviral and zoonotic bunyavirus, causes severe disease in livestock and humans. Here, we report the isolation of a panel of monoclonal antibodies (mAbs) from the B cells of immune individuals following natural infection in Kenya or immunization with MP-12 vaccine. The B cell responses of individuals who were vaccinated or naturally infected recognized similar epitopes on both Gc and Gn proteins. The Gn-specific mAbs and two mAbs that do not recognize either monomeric Gc or Gn alone but recognized the hetero-oligomer glycoprotein complex (Gc+Gn) when Gc and Gn were coexpressed exhibited potent neutralizing activities in vitro, while Gc-specific mAbs exhibited relatively lower neutralizing capacity. The two Gc+Gn-specific mAbs and the Gn domain A-specific mAbs inhibited RVFV fusion to cells, suggesting that mAbs can inhibit the exposure of the fusion loop in Gc, a class II fusion protein, and thus prevent fusion by an indirect mechanism without direct fusion loop contact. Competition-binding analysis with coexpressed Gc/Gn and mutagenesis library screening indicated that these mAbs recognize four major antigenic sites, with two sites of vulnerability for neutralization on Gn. In experimental models of infection in mice, representative mAbs recognizing three of the antigenic sites reduced morbidity and mortality when used at a low dose in both prophylactic and therapeutic settings. This study identifies multiple candidate mAbs that may be suitable for use in humans against RVFV infection and highlights fusion inhibition against bunyaviruses as a potential contributor to potent antibody-mediated neutralization.
Asunto(s)
Anticuerpos Neutralizantes/inmunología , Anticuerpos Antivirales/inmunología , Virus de la Fiebre del Valle del Rift/inmunología , Proteínas Virales de Fusión/inmunología , Animales , Anticuerpos Monoclonales/inmunología , Línea Celular Tumoral , Células Cultivadas , Chlorocebus aethiops , Epítopos/química , Epítopos/inmunología , Células HEK293 , Humanos , Ratones , Ratones Endogámicos C57BL , Células Vero , Proteínas Virales de Fusión/químicaRESUMEN
Live-attenuated virus vaccines are highly effective in preventing viral disease but carry intrinsic risks of residual virulence and reversion to pathogenicity. The classically derived Candid#1 virus protects seasonal field workers in Argentina against zoonotic infection by Junín virus (JUNV) but is not approved in the United States, in part due to the potential for reversion at the attenuating locus, a phenylalanine-to-isoleucine substitution at position 427 in the GP2 subunit of the GPC envelope glycoprotein. Previously, we demonstrated facile reversion of recombinant Candid#1 (rCan) in cell culture and identified an epistatic interaction between the attenuating I427 and a secondary K33S mutation in the stable signal peptide (SSP) subunit of GPC that imposes an evolutionary barrier to reversion. The magnitude of this genetic barrier is manifest in our repeated failures to rescue the hypothetical revertant virus. In this study, we show that K33S rCan is safe and attenuated in guinea pigs and capable of eliciting potent virus-neutralizing antibodies. Immunized animals are fully protected against lethal challenge with virulent JUNV. In addition, we employed a more permissive model of infection in neonatal mice to investigate genetic reversion. RNA sequence analysis of the recovered virus identified revertant viruses in pups inoculated with the parental rCan virus and none in mice receiving K33S rCan (P < 0.0001). Taken together, our findings support the further development of K33S rCan as a safe second-generation JUNV vaccine. IMPORTANCE Our most successful vaccines comprise weakened strains of virus that initiate a limited and benign infection in immunized persons. The live-attenuated Candid#1 strain of Junín virus (JUNV) was developed to protect field workers in Argentina from rodent-borne hemorrhagic fever but is not licensed in the United States, in part due to the likelihood of genetic reversion to virulence. A single-amino-acid change in the GPC envelope glycoprotein of the virus is responsible for attenuation, and a single nucleotide change may regenerate the pathogenic virus. Here, we take advantage of a unique genetic interaction between GPC subunits to design a mutant Candid#1 virus that establishes an evolutionary barrier to reversion. The mutant virus (K33S rCan) is fully attenuated and protects immunized guinea pigs against lethal JUNV infection. We find no instances of reversion in mice inoculated with K33S rCan. This work supports the further development of K33S rCan as a second-generation JUNV vaccine.
Asunto(s)
Fiebre Hemorrágica Americana/prevención & control , Virus Junin/inmunología , Vacunas Virales/inmunología , Animales , Anticuerpos Antivirales/biosíntesis , Anticuerpos Antivirales/inmunología , Chlorocebus aethiops , Cobayas , Fiebre Hemorrágica Americana/inmunología , Inmunogenicidad Vacunal , Virus Junin/genética , Virus Junin/patogenicidad , Masculino , Vacunas Atenuadas/genética , Vacunas Atenuadas/inmunología , Vacunas Sintéticas/genética , Vacunas Sintéticas/inmunología , Células Vero , Vacunas Virales/genética , VirulenciaRESUMEN
Several clade B New World arenaviruses (NWAs) can cause severe and often fatal hemorrhagic fever, for which preventive and therapeutic measures are severely limited. These NWAs use human transferrin receptor 1 (hTfR1) as a host cell receptor for virus entry. The most prevalent of the pathogenic NWAs is Junín virus (JUNV), the etiological agent of Argentine hemorrhagic fever. Small animal models of JUNV infection are limited because most laboratory rodent species are refractory to disease. Only guinea pigs are known to develop disease following JUNV infection, but the underlying mechanisms are not well characterized. In the present study, we demonstrate marked susceptibility of Hartley guinea pigs to uniformly lethal disease when challenged with as few as 4 PFU of the Romero strain of JUNV. In vitro, we show that infection of primary guinea pig macrophages results in greater JUNV replication compared to infection of hamster or mouse macrophages. We provide evidence that the guinea pig TfR1 (gpTfR1) is the principal receptor for JUNV, while hamster and mouse orthologs fail to support viral entry/infection of pseudotyped murine leukemia viruses expressing pathogenic NWA glycoproteins or JUNV. Together, our results indicate that gpTfR1 serves as the primary receptor for pathogenic NWAs, enhancing viral infection in guinea pigs.IMPORTANCE JUNV is one of five known NWAs that cause viral hemorrhagic fever in humans. Countermeasures against JUNV infection are limited to immunization with the Candid#1 vaccine and immune plasma, which are available only in Argentina. The gold standard small animal model for JUNV infection is the guinea pig. Here, we demonstrate high sensitivity of this species to severe JUNV infection and identify gpTfR1 as the primary receptor. Use of hTfR1 for host cell entry is a feature shared by pathogenic NWAs. Our results show that expression of gpTfR1 or hTfR1 comparably enhances JUNV virus entry/infectivity. Our findings shed light on JUNV infection in guinea pigs as a model for human disease and suggest that similar pathophysiological mechanisms related to iron sequestration during infection and regulation of TfR1 expression may be shared between humans and guinea pigs. A better understanding of the underlying disease process will guide development of new therapeutic interventions.
Asunto(s)
Virus Junin/inmunología , Virus Junin/patogenicidad , Receptores de Transferrina/metabolismo , Animales , Arenavirus/inmunología , Arenavirus/patogenicidad , Células CHO , Chlorocebus aethiops , Cricetulus , Modelos Animales de Enfermedad , Femenino , Glicoproteínas/metabolismo , Cobayas/inmunología , Cobayas/metabolismo , Células HEK293 , Fiebre Hemorrágica Americana/inmunología , Fiebre Hemorrágica Americana/virología , Fiebres Hemorrágicas Virales/inmunología , Fiebres Hemorrágicas Virales/virología , Humanos , Virus Junin/metabolismo , Macrófagos/virología , Masculino , Receptores de Transferrina/inmunología , Células Vero , Internalización del Virus , Replicación ViralRESUMEN
PURPOSE: To evaluate the in vitro inactivation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with hydrogen peroxide (H2 O2 ) and povidone-iodine (PVP-I) oral antiseptic rinses at clinically recommended concentrations and contact times. MATERIALS AND METHODS: SARS-CoV-2, USA-WA1/2020 strain virus stock was prepared prior to testing by growing in Vero 76 cells. The culture media for prepared virus stock was minimum essential medium (MEM) with 2% fetal bovine serum (FBS) and 50 µg/mL gentamicin. Test compounds consisting of PVP-I oral rinse solutions and H2 O2 aqueous solutions were mixed directly with the virus solution so that the final concentration was 50% of the test compound and 50% of the virus solution. Thus PVP-I was tested at concentrations of 0.5%, 1.25%, and 1.5%, and H2 O2 was tested at 3% and 1.5% concentrations to represent clinically recommended concentrations. Ethanol and water were evaluated in parallel as standard positive and negative controls. All samples were tested at contact periods of 15 seconds and 30 seconds. Surviving virus from each sample was then quantified by standard end-point dilution assay and the log reduction value of each compound compared to the negative control was calculated. RESULTS: After the 15-second and 30-second contact times, PVP-I oral antiseptic rinse at all 3 concentrations of 0.5%, 1.25%, and 1.5% completely inactivated SARS-CoV-2. The H2 O2 solutions at concentrations of 1.5% and 3.0% showed minimal viricidal activity after 15 seconds and 30 seconds of contact time. CONCLUSIONS: SARS-CoV-2 virus was completely inactivated by PVP-I oral antiseptic rinse in vitro, at the lowest concentration of 0.5 % and at the lowest contact time of 15 seconds. Hydrogen peroxide at the recommended oral rinse concentrations of 1.5% and 3.0% was minimally effective as a viricidal agent after contact times as long as 30 seconds. Therefore, preprocedural rinsing with diluted PVP-I in the range of 0.5% to 1.5% may be preferred over hydrogen peroxide during the COVID-19 pandemic.
Asunto(s)
Antiinfecciosos Locales , Betacoronavirus , COVID-19 , Infecciones por Coronavirus , Neumonía Viral , Coronavirus Relacionado al Síndrome Respiratorio Agudo Severo , Antiinfecciosos Locales/farmacología , Infecciones por Coronavirus/epidemiología , Humanos , Peróxido de Hidrógeno/farmacología , Pandemias , Neumonía Viral/epidemiología , Povidona Yodada/farmacología , SARS-CoV-2RESUMEN
PURPOSE: To investigate the optimal contact time and concentration for viricidal activity of oral preparation of povidone-iodine (PVP-I) against SARS-CoV-2 ('corona virus') to mitigate the risk and transmission of the virus in the dental practice. MATERIALS AND METHODS: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) USA-WA1/2020 strain, virus stock was tested against oral antiseptic solutions consisting of aqueous povidone-iodine (PVP-I) as the sole active ingredient. The PVP-I was tested at diluted concentrations of 0.5%, 1%, and 1.5%. Test media without any virus was added to 2 tubes of the compounds to serve as toxicity and neutralization controls. Ethanol (70%) was tested in parallel as a positive control, and water only as a negative control. The test solutions and virus were incubated at room temperature (22 ± 2 °C) for time periods of 15 and 30 seconds. The solution was then neutralized by a 1/10 dilution in minimum essential medium (MEM) 2% fetal bovine serum (FBS), 50 µg/mL gentamicin. Surviving virus from each sample was quantified by standard end-point dilution assay and the log reduction value (LRV) of each compound compared to the negative (water) control was calculated. RESULTS: PVP-I oral antiseptics at all tested concentrations of 0.5%, 1%, and 1.5%, completely inactivated SARS-CoV-2 within 15 seconds of contact. The 70% ethanol control group was unable to completely inactivate SARS-CoV-2 after 15 seconds of contact, but was able to inactivate the virus at 30 seconds of contact. CONCLUSIONS: PVP-I oral antiseptic preparations rapidly inactivated SARS-CoV-2 virus in vitro. The viricidal activity was present at the lowest concentration of 0.5 % PVP-I and at the lowest contact time of 15 seconds. This important finding can justify the use of preprocedural oral rinsing with PVP-I (for patients and health care providers) may be useful as an adjunct to personal protective equipment, for dental and surgical specialties during the COVID-19 pandemic.
Asunto(s)
Antiinfecciosos Locales , Infecciones por Coronavirus , Pandemias , Neumonía Viral , Betacoronavirus , COVID-19 , Humanos , Povidona Yodada , SARS-CoV-2RESUMEN
Lymphocytic choriomeningitis virus (LCMV) poses a substantial risk to immunocompromised individuals. The case fatality rate in recent clusters of LCMV infection in immunosuppressed organ transplantation recipients has exceeded 70%. In the present study, we demonstrate potent antiviral activity of favipiravir against acute, disseminated LCMV infection in NZB mice. Treatment resulted in complete protection against mortality and dramatic reductions in viral loads. In contrast, ribavirin, the current antiviral of choice, was mostly ineffective. Our findings, and the high lethality associated with LCMV infection in transplant recipients, support the consideration of favipiravir as a first-line therapeutic option.
Asunto(s)
Amidas/administración & dosificación , Antivirales/administración & dosificación , Coriomeningitis Linfocítica/tratamiento farmacológico , Virus de la Coriomeningitis Linfocítica/aislamiento & purificación , Pirazinas/administración & dosificación , Carga Viral , Animales , Modelos Animales de Enfermedad , Femenino , Huésped Inmunocomprometido , Coriomeningitis Linfocítica/virología , Masculino , Ratones Endogámicos NZB , Ribavirina/administración & dosificación , Análisis de Supervivencia , Receptores de Trasplantes , Resultado del TratamientoRESUMEN
Lassa virus, the cause of Lassa fever in humans, is endemic to West Africa. Treatment of Lassa fever is primarily supportive, although ribavirin has shown limited efficacy if administered early during infection. We tested favipiravir in Lassa virus-viremic macaques and found that 300 mg/kg daily for 2 weeks successfully treated infection.
Asunto(s)
Amidas/uso terapéutico , Antivirales/uso terapéutico , Fiebre de Lassa/veterinaria , Virus Lassa/aislamiento & purificación , Macaca , Enfermedades de los Monos/tratamiento farmacológico , Pirazinas/uso terapéutico , Amidas/administración & dosificación , Animales , Antivirales/administración & dosificación , Femenino , Inyecciones Subcutáneas/veterinaria , Fiebre de Lassa/tratamiento farmacológico , Pirazinas/administración & dosificación , Distribución Aleatoria , Resultado del TratamientoRESUMEN
Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tick-borne disease endemic in parts of Asia. The etiologic agent, SFTS virus (SFTSV; family Bunyaviridae, genus Phlebovirus) has caused significant morbidity and mortality in China, South Korea, and Japan, with key features of disease being intense fever, thrombocytopenia, and leukopenia. Case fatality rates are estimated to be in the 30% range, and no antivirals or vaccines are approved for use for treatment and prevention of SFTS. There is evidence that in human cells, SFTSV sequesters STAT proteins in replication complexes, thereby inhibiting type I interferon signaling. Here, we demonstrate that hamsters devoid of functional STAT2 are highly susceptible to as few as 10 PFU of SFTSV, with animals generally succumbing within 5 to 6 days after subcutaneous challenge. The disease included marked thrombocytopenia and inflammatory disease characteristic of the condition in humans. Infectious virus titers were present in the blood and most tissues 3 days after virus challenge, and severe inflammatory lesions were found in the spleen and liver samples of SFTSV-infected hamsters. We also show that SFTSV infection in STAT2 knockout (KO) hamsters is responsive to favipiravir treatment, which protected all animals from lethal disease and reduced serum and tissue viral loads by 3 to 6 orders of magnitude. Taken together, our results provide additional insights into the pathogenesis of SFTSV infection and support the use of the newly described STAT2 KO hamster model for evaluation of promising antiviral therapies. IMPORTANCE: Severe fever with thrombocytopenia syndrome (SFTS) is an emerging viral disease for which there are currently no therapeutic options or available vaccines. The causative agent, SFTS virus (SFTSV), is present in China, South Korea, and Japan, and infections requiring medical attention result in death in as many as 30% of the cases. Here, we describe a novel model of SFTS in hamsters genetically engineered to be deficient in a protein that helps protect humans and animals against viral infections. These hamsters were found to be susceptible to SFTSV and share disease features associated with the disease in humans. Importantly, we also show that SFTSV infection in hamsters can be effectively treated with a broad-spectrum antiviral drug approved for use in Japan. Our findings suggest that the new SFTS model will be an excellent resource to better understand SFTSV infection and disease as well as a valuable tool for evaluating promising antiviral drugs.
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Infecciones por Bunyaviridae/virología , Modelos Biológicos , Phlebovirus/fisiología , Amidas/farmacología , Animales , Animales Modificados Genéticamente , Antivirales/farmacología , Infecciones por Bunyaviridae/tratamiento farmacológico , Infecciones por Bunyaviridae/genética , Infecciones por Bunyaviridae/mortalidad , Cricetinae , Modelos Animales de Enfermedad , Susceptibilidad a Enfermedades , Genotipo , Humanos , Fenotipo , Pirazinas/farmacología , Factor de Transcripción STAT2/genéticaRESUMEN
Argentine hemorrhagic fever, caused by Junín virus (JUNV), is the most common of the South American arenaviral hemorrhagic fevers. The disease has a case fatality rate of 15-30% in untreated patients. Although early intervention with immune plasma is effective, diminishing stocks and limited availability outside of Argentina underscores the need for new therapeutics. Ideally, these would be broadly active agents effective against all the pathogenic arenaviruses. The fusion inhibitor LHF-535 and the nucleoside analog favipiravir have shown promise in animal models of Lassa fever, a disease endemic in parts of Africa and the most prominent of the arenaviral hemorrhagic fevers. Against JUNV, a high dose of favipiravir is required to achieve protection in the gold-standard guinea pig infection model. Here, we demonstrate a synergistic effect by the coadministration of LHF-535 with a sub-optimal dose of favipiravir in guinea pigs challenged with JUNV. Administered individually, LHF-535 and sub-optimal favipiravir only delayed the onset of severe disease. However, combined dosing of the drugs afforded complete protection against lethal JUNV infection in guinea pigs. The benefits of the drug combination were also evident by the absence of viremia and infectious virus in tissues compared to guinea pigs treated with only the placebos. Thus, combined targeting of JUNV-endosomal membrane fusion and the viral polymerase with pan-arenaviral LHF-535 and favipiravir may expand their indication beyond Lassa fever, providing a significant barrier to drug resistance.
Asunto(s)
Amidas , Antivirales , Modelos Animales de Enfermedad , Virus Junin , Pirazinas , Pirazinas/farmacología , Pirazinas/administración & dosificación , Pirazinas/uso terapéutico , Animales , Cobayas , Amidas/farmacología , Amidas/uso terapéutico , Amidas/administración & dosificación , Virus Junin/efectos de los fármacos , Antivirales/farmacología , Antivirales/administración & dosificación , Antivirales/uso terapéutico , Fiebre Hemorrágica Americana/tratamiento farmacológico , Fiebre Hemorrágica Americana/virología , Quimioterapia Combinada , Femenino , Sinergismo Farmacológico , Infecciones por Arenaviridae/tratamiento farmacológicoRESUMEN
Killer-cell immunoglobulin-like receptor (KIR) proteins are expressed on natural killer (NK) cells and appear important in innate and adaptive immunity. There are about 14 KIR genes on chromosome 19q13.4, composed of those that inhibit and those that activate NK cell killing. Haplotypes have different combinations of these genes meaning that not all genes are present in a subject. There are two main classes of cognate human leukocyte antigen (HLA) ligands (HLA-Bw4 and HLA-C1/C2) that bind to the inhibitory/activating receptors. As a general rule, the inhibitory state is maintained except when virally infected or tumor cells are encountered; however, both increased activation and inhibition states have been associated with susceptibility and protection against numerous disease states including cancer, arthritis, and psoriasis. Utilizing DNA from 158 Caucasian subjects with autism and 176 KIR control subjects we show for the first time a highly significant increase in four activating KIR genes (2DS5, 3DS1, 2DS1 and 2DS4) as measured by chi square values and odds ratios. In addition, our data suggests a highly significant increase in the activating KIR gene 2DS1 and its cognate HLA-C2 ligand (2DS1+C2; p = 0.00003 [Odds ratio = 2.87]). This information ties together two major immune gene complexes, the human leukocyte complex and the leukocyte receptor complex, and may partially explain immune abnormalities observed in many subjects with autism.
Asunto(s)
Trastorno Autístico/inmunología , Antígenos HLA/inmunología , Receptores KIR/inmunología , Trastorno Autístico/genética , Estudios de Cohortes , ADN/genética , Femenino , Frecuencia de los Genes , Genotipo , Antígenos HLA/genética , Humanos , Células Asesinas Naturales/metabolismo , Masculino , Oportunidad Relativa , Reacción en Cadena de la Polimerasa , Receptores KIR/genéticaRESUMEN
Very preterm birth (VPTB) is a leading cause of infant mortality, morbidity and racial disparity in the US. The underlying causes of VPTB are multiple and poorly understood. The California Very Preterm Birth Study was conducted to discover maternal and infant genetic and environmental factors associated with VPTB. This paper describes the study design, population, data and specimen collection, laboratory methods and characteristics of the study population. Using a large, population-based cohort created through record linkage of livebirths delivered from 2000 to 2007 in five counties of southern California, and existing data and banked specimens from statewide prenatal and newborn screening, 1100 VPTB cases and 796 control mother-infant pairs were selected for study (385/200 White, 385/253 Hispanic and 330/343 Black cases/controls, respectively). Medical record abstraction of cases was conducted at over 50 hospitals to identify spontaneous VPTB, improve accuracy of gestational age, obtain relevant clinical data and exclude cases that did not meet eligibility criteria. VPTB was defined as birth at <32 weeks in Whites and Hispanics and <34 weeks in Blacks. Approximately 55% of all VPTBs were spontaneous and 45% had medical indications or other exclusions. Of the spontaneous VPTBs, approximately 41% were reported to have chorioamnionitis. While the current focus of the California Very Preterm Birth Study is to assess the role of candidate genetic markers on spontaneous VPTB, its design enables the pursuit of other research opportunities to identify social, clinical and biological determinants of different types of VPTB with the ultimate aim of reducing infant mortality, morbidity and racial disparities in these health outcomes in the US and elsewhere.
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Nacimiento Prematuro/epidemiología , Proyectos de Investigación , Negro o Afroamericano , California/epidemiología , Estudios de Casos y Controles , Femenino , Edad Gestacional , Hispánicos o Latinos , Humanos , Recién Nacido , Recien Nacido Prematuro , Embarazo , Población BlancaRESUMEN
Infections by pathogenic New World mammarenaviruses (NWM)s, including Junín virus (JUNV), can result in a severe life-threatening viral hemorrhagic fever syndrome. In the absence of FDA-licensed vaccines or antivirals, these viruses are considered high priority pathogens. The mammarenavirus envelope glycoprotein complex (GPC) mediates pH-dependent fusion between viral and cellular membranes, which is essential to viral entry and may be vulnerable to small-molecule inhibitors that disrupt this process. ARN-75039 is a potent fusion inhibitor of a broad spectrum of pseudotyped and native mammarenaviruses in cell culture and Tacaribe virus infection in mice. In the present study, we evaluated ARN-75039 against pathogenic JUNV in the rigorous guinea pig infection model. The compound was well-tolerated and had favorable pharmacokinetics supporting once-per-day oral dosing in guinea pigs. Importantly, significant protection against JUNV challenge was observed even when ARN-75039 was withheld until 6 days after the viral challenge when clinical signs of disease are starting to develop. We also show that ARN-75039 combination treatment with favipiravir, a viral polymerase inhibitor, results in synergistic activity in vitro and improves survival outcomes in JUNV-challenged guinea pigs. Our findings support the continued development of ARN-75039 as an attractive therapeutic candidate for treating mammarenaviral hemorrhagic fevers, including those associated with NWM infection.
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Arenaviridae , Fiebre Hemorrágica Americana , Fiebres Hemorrágicas Virales , Virus Junin , Cobayas , Ratones , Animales , Fiebre Hemorrágica Americana/tratamiento farmacológico , Pirazinas/farmacología , Pirazinas/uso terapéutico , Amidas/farmacología , Amidas/uso terapéutico , Antirretrovirales/farmacologíaRESUMEN
INTRODUCTION: Severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) is the pathogen responsible for the global pandemic of coronavirus disease 2019 (COVID-19). From the first reported cases in December 2019, the virus has spread to over 4 million people worldwide. Human-to-human transmission occurs mainly through the aerosolization of respiratory droplets. Transmission also occurs through contact with contaminated surfaces and other fomites. Improved antisepsis of human and nonhuman surfaces has been identified as a key feature of transmission reduction. There are no previous studies of povidone iodine (PVP-I) against SARS-CoV-2. This study evaluated nasal and oral antiseptic formulations of PVP-I for virucidal activity against SARS-CoV-2. This is the first report on the efficacy of PVP-I against the virus that causes COVID-19. METHODS: Povidone iodine nasal antiseptic formulations and PVP-I oral rinse antiseptic formulations from 1% to 5% concentrations as well as controls were studied for virucidal efficacy against the SARS-CoV-2. Test compounds were evaluated for ability to inactivate SARS-CoV-2 as measured in a virucidal assay. SARS-CoV-2 was exposed directly to the test compound for 60 seconds, compounds were then neutralized, and surviving virus was quantified. RESULTS: All concentrations of nasal antiseptics and oral rinse antiseptics evaluated completely inactivated the SARS-CoV-2. CONCLUSIONS: Nasal and oral PVP-I antiseptic solutions are effective at inactivating the SARS-CoV-2 at a variety of concentrations after 60-second exposure times. The formulations tested may help to reduce the transmission of SARS-CoV-2 if used for nasal decontamination, oral decontamination, or surface decontamination in known or suspected cases of COVID-19.
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Antiinfecciosos Locales/farmacología , COVID-19/prevención & control , Viabilidad Microbiana/efectos de los fármacos , Povidona Yodada/farmacología , SARS-CoV-2/efectos de los fármacos , Administración Tópica , COVID-19/transmisión , Humanos , Técnicas In Vitro , Mucosa Bucal , Antisépticos Bucales , Lavado Nasal (Proceso) , Mucosa NasalRESUMEN
Several arenaviruses, including Lassa and Lujo viruses in Africa and five New World arenavirus (NWA) species in the Americas, cause life-threatening viral hemorrhagic fevers. In the absence of licensed antiviral therapies, these viruses pose a significant public health risk. The envelope glycoprotein complex (GPC) mediates arenavirus entry through a pH-dependent fusion of the viral and host endosomal membranes. It thus is recognized as a viable target for small-molecule fusion inhibitors. Here, we report on the antiviral activity and pre-clinical development of the novel broad-spectrum arenavirus fusion inhibitors, ARN-75039 and ARN-75041. In Tacaribe virus (TCRV) pseudotyped and native virus assays, the ARN compounds were active in the low to sub-nanomolar range with selectivity indices exceeding 1000. Pharmacokinetic analysis of the orally administered compounds revealed an extended half-life in mice supporting once-daily dosing, and the compounds were well tolerated at the highest tested dose of 100 mg/kg. In a proof-of-concept prophylactic efficacy study, doses of 10 and 35 mg/kg of either compound dramatically improved survival outcome and potently inhibited TCRV replication in serum and various tissues. Additionally, in contrast to surviving mice that received ribavirin or placebo, animals treated with ARN-75039 or ARN-75041 were cured of TCRV infection. In a follow-up study with ARN-75039, impressive therapeutic efficacy was demonstrated under conditions where treatment was withheld until after the onset of disease. Taken together, the data strongly support the continued development of ARN-75039 as a candidate therapeutic for the treatment of severe arenaviral diseases.
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Antivirales/farmacología , Infecciones por Arenaviridae/tratamiento farmacológico , Arenavirus del Nuevo Mundo/efectos de los fármacos , Fusión de Membrana/efectos de los fármacos , Bibliotecas de Moléculas Pequeñas/farmacología , Administración Oral , Animales , Antivirales/farmacocinética , Chlorocebus aethiops , Masculino , Ratones , Ribavirina/farmacología , Bibliotecas de Moléculas Pequeñas/farmacocinética , Células Vero , Proteínas del Envoltorio Viral/química , Proteínas del Envoltorio Viral/metabolismo , Internalización del Virus/efectos de los fármacosRESUMEN
Broadly reactive antibodies targeting the influenza A virus hemagglutinin (HA) head domain are thought to be rare and to require extensive somatic mutations or unusual structural features to achieve breadth against divergent HA subtypes. Here we describe common genetic and structural features of protective human antibodies from several individuals recognizing the trimer interface (TI) of the influenza A HA head, a recently identified site of vulnerability. We examined the sequence of TI-reactive antibodies, determined crystal structures for TI antibody-antigen complexes, and analyzed the contact residues of the antibodies on HA to discover common genetic and structural features of TI antibodies. Our data reveal that many TI antibodies are encoded by a light chain variable gene segment incorporating a shared somatic mutation. In addition, these antibodies have a shared acidic residue in the heavy chain despite originating from diverse heavy chain variable gene segments. These studies show that the TI region of influenza A HA is a major antigenic site with conserved structural features that are recognized by a common human B cell public clonotype. The canonical nature of this antibody-antigen interaction suggests that the TI epitope might serve as an important target for structure-based vaccine design.
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Anticuerpos Neutralizantes/química , Anticuerpos Antivirales/química , Glicoproteínas Hemaglutininas del Virus de la Influenza/química , Subtipo H1N1 del Virus de la Influenza A/química , Anticuerpos Neutralizantes/inmunología , Anticuerpos Antivirales/inmunología , Epítopos/química , Epítopos/inmunología , Glicoproteínas Hemaglutininas del Virus de la Influenza/inmunología , Humanos , Subtipo H1N1 del Virus de la Influenza A/inmunología , Vacunas contra la Influenza/química , Vacunas contra la Influenza/inmunologíaRESUMEN
Background The initial global outbreak of the novel coronavirus disease 2019 (COVID-2019) pandemic, which is responsible for the severe acute respiratory syndrome 2 (SARS-CoV-2), shares similarities with the severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV) and behaves similarly to influenza with a high intranasal viral load. The genome sequence of COVID-19 opened the opportunity for multiple in vitro and clinical trials, but we still do not have a clear path to treatment. Chlorpheniramine maleate (CPM) is a safe and effective antihistamine with potent antiviral activity against various strains of influenza A/B, thus suggesting that CPM has broad antiviral activity. We tested the virucidal potential of CPM in a nasal spray composition currently in development as an anti-allergy medication. Methods The virucidal activity of CPM was tested using viral stock of SARS-CoV-2, USA-WA1/2020 strain in Vero 76 infected cells. The endpoint titer 50% cell culture infection dose (CCID50) values were calculated using the Reed-Muench (1948) equation. Three independent replicates of each sample were tested, and the average and standard deviation were calculated. Results were compared with untreated controls using one-way ANOVA (analysis of variance) with Dunnett's multiple comparison test in GraphPad Prism (version 8) software. Results After 25 minutes of contact time, the nasal spray reduced the levels of the virus from 4.2 to 1.7 log10 CCID50 per 0.1 mL, a statistically significant 2.5 log reduction value or 99.7% reduction in the viral load. Conclusions This study demonstrates the strong virucidal effect against SARS-CoV-2 of a nasal spray containing CPM. Given that CPM has broad antiviral effects against influenza and virucidal effect against SARS-CoV-2, we propose two further studies: a randomized placebo-controlled study of intranasally delivered chlorpheniramine in patients with mild-to-moderate SARS-CoV-2 and a second study aiming to determine the potential antiviral and adjuvant effects of CPM plus hydroxychloroquine, versus hydroxychloroquine alone, in hospitalized patients with SARS-CoV-2.
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Importance: Research is needed to demonstrate the efficacy of nasal povidone-iodine (PVP-I) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Objective: To evaluate the in vitro efficacy of PVP-I nasal antiseptic for the inactivation of SARS-CoV-2 at clinically significant contact times of 15 and 30 seconds. Interventions: The SARS-CoV-2, USA-WA1/2020 strain, virus stock was tested against nasal antiseptic solutions consisting of aqueous PVP-I as the sole active ingredient. Povidone-iodine was tested at diluted concentrations of 0.5%, 1.25%, and 2.5% and compared with controls. The test solutions and virus were incubated at mean (SD) room temperature of 22 (2) °C for time periods of 15 and 30 seconds. Design and Setting: This controlled in vitro laboratory research study used 3 different concentrations of study solution and ethanol, 70%, as a positive control on test media infected with SARS-CoV-2. Test media without virus were added to 2 tubes of the compounds to serve as toxicity and neutralization controls. Ethanol, 70%, was tested in parallel as a positive control and water only as a negative control. Main Outcomes and Measures: The primary study outcome measurement was the log reduction value after 15 seconds and 30 seconds of given treatment. Surviving virus from each sample was quantified by standard end point dilution assay, and the log reduction value of each compound was compared with the negative (water) control. Results: Povidone-iodine nasal antiseptics at concentrations (0.5%, 1.25%, and 2.5%) completely inactivated SARS-CoV-2 within 15 seconds of contact as measured by log reduction value of greater than 3 log10 of the 50% cell culture infectious dose of the virus. The ethanol, 70%, positive control did not completely inactivate SARS-CoV-2 after 15 seconds of contact. The nasal antiseptics tested performed better than the standard positive control routinely used for in vitro assessment of anti-SARS-CoV-2 agents at a contact time of 15 seconds. No cytotoxic effects on cells were observed after contact with each of the nasal antiseptics tested. Conclusions and Relevance: Povidone-iodine nasal antiseptic solutions at concentrations as low as 0.5% rapidly inactivate SARS-CoV-2 at contact times as short as 15 seconds. Intranasal use of PVP-I has demonstrated safety at concentrations of 1.25% and below and may play an adjunctive role in mitigating viral transmission beyond personal protective equipment.
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Antiinfecciosos Locales/administración & dosificación , Control de Infecciones/métodos , Nariz/virología , Povidona Yodada/administración & dosificación , SARS-CoV-2/efectos de los fármacos , Administración Intranasal , COVID-19/transmisión , COVID-19/virología , Relación Dosis-Respuesta a Droga , HumanosRESUMEN
PT150 is a clinical-stage molecule, taken orally, with a strong safety profile having completed Phase 1 and Phase 2 clinical trials for its original use as an antidepressant. It has an active IND for COVID-19. Antiviral activities have been found for PT150 and other members of its class in a variety of virus families; thus, it was now tested against SARS-CoV-2 in human bronchial epithelial lining cells and showed effective 90% inhibitory antiviral concentration (EC90) of 5.55 µM. PT150 is a member of an extended platform of novel glucocorticoid receptor (GR) and androgen receptor (AR) modulating molecules. In vivo, their predominant net effect is one of systemic glucocorticoid antagonism, but they also show direct downregulation of AR and minor GR agonism at the cellular level. We hypothesize that anti-SARS-CoV-2 activity depends in part on this AR downregulation through diminished TMPRSS2 expression and modulation of ACE2 activity. Given that hypercortisolemia is now suggested to be a significant co-factor for COVID-19 progression, we also postulate an additive role for its potent immunomodulatory effects through systemic antagonism of cortisol.