RESUMEN
Monkeypox (MPXV) and cowpox (CPXV) are emerging agents that cause severe human infections on an intermittent basis, and variola virus (VARV) has potential for use as an agent of bioterror. Vaccinia immune globulin (VIG) has been used therapeutically to treat severe orthopoxvirus infections but is in short supply. We generated a large panel of orthopoxvirus-specific human monoclonal antibodies (Abs) from immune subjects to investigate the molecular basis of broadly neutralizing antibody responses for diverse orthopoxviruses. Detailed analysis revealed the principal neutralizing antibody specificities that are cross-reactive for VACV, CPXV, MPXV, and VARV and that are determinants of protection in murine challenge models. Optimal protection following respiratory or systemic infection required a mixture of Abs that targeted several membrane proteins, including proteins on enveloped and mature virion forms of virus. This work reveals orthopoxvirus targets for human Abs that mediate cross-protective immunity and identifies new candidate Ab therapeutic mixtures to replace VIG.
Asunto(s)
Anticuerpos Monoclonales/inmunología , Anticuerpos Neutralizantes/inmunología , Anticuerpos Antivirales/inmunología , Especificidad de Anticuerpos , Infecciones por Poxviridae/inmunología , Viruela Vacuna/inmunología , Virus de la Viruela Vacuna/inmunología , Reacciones Cruzadas , Humanos , Leucocitos Mononucleares/inmunología , Mpox/inmunología , Monkeypox virus/inmunología , Viruela/inmunología , Vaccinia/inmunología , Virus Vaccinia/inmunología , Virus de la Viruela/inmunologíaRESUMEN
Antibody responses to viral infections are sustained for decades by long-lived plasma cells (LLPCs). However, LLPCs have yet to be characterized in humans. Here we used CD19, CD38, and CD138 to identify four PC subsets in human bone marrow (BM). We found that the CD19(-)CD38(hi)CD138(+) subset was morphologically distinct, differentially expressed PC-associated genes, and exclusively contained PCs specific for viral antigens to which the subjects had not been exposed for more than 40 years. Protein sequences of measles- and mumps-specific circulating antibodies were encoded for by CD19(-)CD38(hi)CD138(+) PCs in the BM. Finally, we found that CD19(-)CD38(hi)CD138(+) PCs had a distinct RNA transcriptome signature and human immunoglobulin heavy chain (VH) repertoire that was relatively uncoupled from other BM PC subsets and probably represents the B cell response's "historical record" of antigenic exposure. Thus, our studies define human LLPCs and provide a mechanism for the life-long maintenance of anti-viral antibodies in the serum.
Asunto(s)
Anticuerpos Antivirales/inmunología , Células de la Médula Ósea/inmunología , Virus del Sarampión/inmunología , Virus de la Parotiditis/inmunología , Células Plasmáticas/inmunología , ADP-Ribosil Ciclasa 1/metabolismo , Adulto , Anciano , Anticuerpos Antivirales/sangre , Antígenos CD19/metabolismo , Humanos , Cadenas Pesadas de Inmunoglobulina/genética , Cadenas Pesadas de Inmunoglobulina/inmunología , Glicoproteínas de Membrana/metabolismo , Persona de Mediana Edad , ARN Mensajero/genética , Sindecano-1/metabolismo , Adulto JovenRESUMEN
BACKGROUND: It is unclear whether human immunodeficiency virus (HIV) infection results in permanent loss of T-cell memory or if it affects preexisting antibodies to childhood vaccinations or infections. METHODS: We conducted a matched cohort study involving 50 pairs of HIV-infected and HIV-uninfected women. Total memory T-cell responses were measured after anti-CD3 or vaccinia virus (VV) stimulation to measure T cells elicited after childhood smallpox vaccination. VV-specific antibodies were measured by means of enzyme-linked immunosorbent assay (ELISA). RESULTS: There was no difference between HIV-infected and HIV-uninfected study participants in terms of CD4+ T-cell responses after anti-CD3 stimulation (P = .19) although HIV-infected participants had significantly higher CD8+ T-cell responses (P = .03). In contrast, there was a significant loss in VV-specific CD4+ T-cell memory among HIV-infected participants (P = .04) whereas antiviral CD8+ T-cell memory remained intact (P > .99). VV-specific antibodies were maintained indefinitely among HIV-uninfected participants (half-life, infinity; 95% confidence interval, 309 years to infinity) but declined rapidly among HIV-infected participants (half-life; 39 years; 24-108 years; P = .001). CONCLUSIONS: Despite antiretroviral therapy-associated improvement in CD4+ T-cell counts (nadir, <200/µL; >350/µL after antiretroviral therapy), antigen-specific CD4+ T-cell memory to vaccinations or infections that occurred before HIV infection did not recover after immune reconstitution, and a previously unrealized decline in preexisting antibody responses was observed.
Asunto(s)
Fármacos Anti-VIH/uso terapéutico , Linfocitos T CD4-Positivos/inmunología , Infecciones por VIH/tratamiento farmacológico , Infecciones por VIH/inmunología , Reconstitución Inmune , Memoria Inmunológica , Adulto , Anticuerpos Antivirales/sangre , Anticuerpos Antivirales/inmunología , Complejo CD3/inmunología , Linfocitos T CD8-positivos/inmunología , Estudios de Cohortes , Femenino , Humanos , Activación de Linfocitos , Vacuna contra Viruela/inmunología , Factores de Tiempo , Virus Vaccinia/inmunologíaRESUMEN
BACKGROUND: Many adult immunization schedules recommend that tetanus and diphtheria vaccination be performed every 10 years. In light of current epidemiological trends of disease incidence and rates of vaccine-associated adverse events, the 10-year revaccination schedule has come into question. METHODS: We performed cross-sectional analysis of serum antibody titers in 546 adult subjects stratified by age or sex. All serological results were converted to international units after calibration with international serum standards. RESULTS: Approximately 97% of the population was seropositive to tetanus and diphtheria as defined by a protective serum antibody titer of ≥0.01 IU/mL. Mean antibody titers were 3.6 and 0.35 IU/mL against tetanus and diphtheria, respectively. Antibody responses to tetanus declined with an estimated half-life of 14 years (95% confidence interval, 11-17 years), whereas antibody responses to diphtheria were more long-lived and declined with an estimated half-life of 27 years (18-51 years). Mathematical models combining antibody magnitude and duration predict that 95% of the population will remain protected against tetanus and diphtheria for ≥30 years without requiring further booster vaccination. CONCLUSIONS: These studies demonstrate that durable levels of protective antitoxin immunity exist in the majority of vaccinated individuals. Together, this suggests that it may no longer be necessary to administer booster vaccinations every 10 years and that the current adult vaccination schedule for tetanus and diphtheria should be revisited.
Asunto(s)
Anticuerpos Antibacterianos/sangre , Toxina Diftérica/inmunología , Vacuna contra Difteria y Tétanos , Esquemas de Inmunización , Toxina Tetánica/inmunología , Adulto , Anciano , Anciano de 80 o más Años , Formación de Anticuerpos , Estudios Transversales , Femenino , Semivida , Humanos , Inmunización Secundaria , Masculino , Persona de Mediana Edad , Adulto JovenRESUMEN
Infections with monkeypox, cowpox and weaponized variola virus remain a threat to the increasingly unvaccinated human population, but little is known about their mechanisms of virulence and immune evasion. We now demonstrate that B22 proteins, encoded by the largest genes of these viruses, render human T cells unresponsive to stimulation of the T cell receptor by MHC-dependent antigen presentation or by MHC-independent stimulation. In contrast, stimuli that bypass TCR-signaling are not inhibited. In a non-human primate model of monkeypox, virus lacking the B22R homologue (MPXVΔ197) caused only mild disease with lower viremia and cutaneous pox lesions compared to wild type MPXV which caused high viremia, morbidity and mortality. Since MPXVΔ197-infected animals displayed accelerated T cell responses and less T cell dysregulation than MPXV US2003, we conclude that B22 family proteins cause viral virulence by suppressing T cell control of viral dissemination.
Asunto(s)
Evasión Inmune , Infecciones por Poxviridae/inmunología , Poxviridae/patogenicidad , Linfocitos T/inmunología , Linfocitos T/virología , Proteínas Virales/fisiología , Animales , Células CHO , Células Cultivadas , Chlorocebus aethiops , Cricetinae , Cricetulus , Femenino , Células HEK293 , Humanos , Evasión Inmune/genética , Células Jurkat , Macaca mulatta , Ratones , Ratones Endogámicos BALB C , Mpox/inmunología , Poxviridae/genética , Poxviridae/inmunologíaRESUMEN
Virus-specific CD8(+) T cells develop the ability to function in an "innate" capacity by responding to a remarkable array of cytokines in a TCR-independent manner. Although several cytokines such as IL-12 and IL-18 have been identified as key regulators of CD8(+) T-cell activation, the role of other cytokines and the ways in which they interact with each other remain unclear. Here, we have used an unbiased, systematic approach to examine the effects of 1,849 cytokine combinations on virus-specific CD8(+) T-cell activation. This study identifies several unexpected cytokine combinations that synergize to induce antigen-independent IFNγ production and CD69 up-regulation by CD8(+) T cells in addition to cytokines that exhibit differential regulatory functions, with the ability to either enhance or inhibit T-cell IFNγ production, depending on which cytokine partner is present. These findings underscore the complexity of cytokine interactions while also providing insight into the multifaceted regulatory network controlling virus-specific CD8(+) T-cell functions.
Asunto(s)
Linfocitos T CD8-positivos/inmunología , Citocinas/fisiología , Inmunidad Innata , Activación de Linfocitos , Animales , Citocinas/biosíntesis , Femenino , Humanos , Memoria Inmunológica , RatonesRESUMEN
BACKGROUND: Atopic dermatitis (AD) is a common inflammatory skin disease with a global prevalence ranging from 3% to 20%. Patients with AD have an increased risk for complications after viral infection (eg, herpes simplex virus), and vaccination of patients with AD with live vaccinia virus is contraindicated because of a heightened risk of eczema vaccinatum, a rare but potentially lethal complication associated with smallpox vaccination. OBJECTIVE: We sought to develop a better understanding of immunity to cutaneous viral infection in patients with AD. METHODS: In a double-blind randomized study we investigated the safety and immunogenicity of live attenuated yellow fever virus (YFV) vaccination of nonatopic subjects and patients with AD after standard subcutaneous inoculation or transcutaneous vaccination administered with a bifurcated needle. Viremia, neutralizing antibody, and antiviral T-cell responses were analyzed for up to 30 days after vaccination. RESULTS: YFV vaccination administered through either route was well tolerated. Subcutaneous vaccination resulted in higher seroconversion rates than transcutaneous vaccination but elicited similar antiviral antibody levels and T-cell responses in both the nonatopic and AD groups. After transcutaneous vaccination, both groups mounted similar neutralizing antibody responses, but patients with AD demonstrated lower antiviral T-cell responses by 30 days after vaccination. Among transcutaneously vaccinated subjects, a significant inverse correlation between baseline IgE levels and the magnitude of antiviral antibody and CD4(+) T-cell responses was observed. CONCLUSIONS: YFV vaccination of patients with AD through the transcutaneous route revealed that high baseline IgE levels provide a potential biomarker for predicting reduced virus-specific immune memory after transcutaneous infection with a live virus.
Asunto(s)
Dermatitis Atópica/inmunología , Vacuna contra la Fiebre Amarilla/administración & dosificación , Fiebre Amarilla/prevención & control , Administración Cutánea , Adulto , Anticuerpos Antivirales/sangre , Células Cultivadas , Dermatitis Atópica/sangre , Dermatitis Atópica/virología , Método Doble Ciego , Femenino , Humanos , Inmunoglobulina E/sangre , Leucocitos Mononucleares , Masculino , ARN Viral/análisis , Linfocitos T/inmunología , Vacunación , Viremia , Vacuna contra la Fiebre Amarilla/efectos adversosRESUMEN
Yellow fever virus (YFV) is endemic in >40 countries and causes viscerotropic disease with up to 20%-60% mortality. Successful live-attenuated yellow fever (YF) vaccines were developed in the mid-1930s, but their use is restricted or formally contraindicated in vulnerable populations including infants, the elderly, and people with compromised immune systems. In these studies, we describe the development of a next-generation hydrogen peroxide-inactivated YF vaccine and determine immune correlates of protection based on log neutralizing index (LNI) and neutralizing titer-50% (NT50) studies. In addition, we compare neutralizing antibody responses and protective efficacy of hydrogen peroxide-inactivated YF vaccine candidates to live-attenuated YFV-17D (YF-VAX) in a rhesus macaque model of viscerotropic YF. Our results indicate that an optimized, inactivated YF vaccine elicits protective antibody responses that prevent viral dissemination and lethal infection in rhesus macaques and may be a suitable alternative for vaccinating vulnerable populations who are not eligible to receive replicating live-attenuated YF vaccines.
Asunto(s)
Anticuerpos Neutralizantes , Anticuerpos Antivirales , Modelos Animales de Enfermedad , Peróxido de Hidrógeno , Macaca mulatta , Vacunas de Productos Inactivados , Vacuna contra la Fiebre Amarilla , Fiebre Amarilla , Virus de la Fiebre Amarilla , Animales , Vacunas de Productos Inactivados/inmunología , Vacuna contra la Fiebre Amarilla/inmunología , Fiebre Amarilla/prevención & control , Fiebre Amarilla/inmunología , Virus de la Fiebre Amarilla/inmunología , Anticuerpos Neutralizantes/inmunología , Anticuerpos Antivirales/inmunología , Vacunas Atenuadas/inmunología , Chlorocebus aethiops , Células Vero , HumanosRESUMEN
Approximately 50% of the US population received smallpox vaccinations before routine immunization ceased in 1972 for civilians and in 1990 for military personnel. Several studies have shown long-term immunity after smallpox vaccination, but skepticism remains as to whether this will translate into full protection against the onset of orthopoxvirus-induced disease. The US monkeypox outbreak of 2003 provided the opportunity to examine this issue. Using independent and internally validated diagnostic approaches with >or=95% sensitivity and >or=90% specificity for detecting clinical monkeypox infection, we identified three previously unreported cases of monkeypox in preimmune individuals at 13, 29 and 48 years after smallpox vaccination. These individuals were unaware that they had been infected because they were spared any recognizable disease symptoms. Together, this shows that the US monkeypox outbreak was larger than previously realized and, more importantly, shows that cross-protective antiviral immunity against West African monkeypox can potentially be maintained for decades after smallpox vaccination.
Asunto(s)
Mpox/inmunología , Mpox/prevención & control , Vacuna contra Viruela/inmunología , Animales , Anticuerpos Antivirales , Reacciones Cruzadas , Brotes de Enfermedades , Reservorios de Enfermedades , Humanos , Mpox/transmisión , Sciuridae/virología , Linfocitos T/inmunología , Factores de Tiempo , Wisconsin/epidemiología , ZoonosisRESUMEN
The threat of a smallpox-based bioterrorist event or a human monkeypox outbreak has heightened the importance of new, safe vaccine approaches for these pathogens to complement older poxviral vaccine platforms. As poxviruses are large, complex viruses, they present technological challenges for simple recombinant vaccine development where a multicomponent mixtures of vaccine antigens are likely important in protection. We report that a synthetic, multivalent, highly concentrated, DNA vaccine delivered by a minimally invasive, novel skin electroporation microarray can drive polyvalent immunity in macaques, and offers protection from a highly pathogenic monkeypox challenge. Such a diverse, high-titer antibody response produced against 8 different DNA-encoded antigens delivered simultaneously in microvolumes has not been previously described. These studies represent a significant improvement in the efficiency of the DNA vaccine platform, resulting in immune responses that mimic live viral infections, and would likely have relevance for vaccine design against complex human and animal pathogens.
Asunto(s)
Mpox/prevención & control , Vacuna contra Viruela/inmunología , Vacunas de ADN/inmunología , Animales , Anticuerpos Antivirales/sangre , Electroporación/métodos , Humanos , Macaca mulatta , Vacuna contra Viruela/administración & dosificación , Análisis de Supervivencia , Vacunas de ADN/administración & dosificaciónRESUMEN
Outbreaks of smallpox (i.e., caused by variola virus) resulted in up to 30% mortality, but those who survived smallpox infection were regarded as immune for life. Early studies described the levels of neutralizing antibodies induced after infection, but smallpox was eradicated before contemporary methods for quantifying T-cell memory were developed. To better understand the levels and duration of immunity after smallpox infection, we performed a case-control study comparing antiviral CD4(+) and CD8(+) T-cell responses and neutralizing antibody levels of 24 smallpox survivors with the antiviral immunity observed in 60 smallpox-vaccinated (i.e., vaccinia virus-immune) control subjects. We found that the duration of immunity following smallpox infection was remarkably similar to that observed after smallpox vaccination, with antiviral T-cell responses that declined slowly over time and antiviral antibody responses that remained stable for decades after recovery from infection. These results indicate that severe, potentially life-threatening disease is not required for the development of sustainable long-term immunity. This study shows that the levels of immunity induced following smallpox vaccination are comparable in magnitude to that achieved through natural variola virus infection, and this may explain the notable success of vaccination in eradicating smallpox, one of the world's most lethal diseases.
Asunto(s)
Antivirales/inmunología , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/inmunología , Vacuna contra Viruela/inmunología , Viruela/prevención & control , Virus de la Viruela/inmunología , Adulto , Anciano , Anciano de 80 o más Años , Anticuerpos Antivirales/sangre , Estudios de Casos y Controles , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Memoria Inmunológica , Masculino , Persona de Mediana Edad , Viruela/virología , Vacuna contra Viruela/uso terapéutico , Factores de Tiempo , VacunaciónRESUMEN
Although naturally occurring smallpox was eliminated through the efforts of the World Health Organization Global Eradication Program, it remains possible that smallpox could be intentionally released. Here we examine the magnitude and duration of antiviral immunity induced by one or more smallpox vaccinations. We found that more than 90% of volunteers vaccinated 25-75 years ago still maintain substantial humoral or cellular immunity (or both) against vaccinia, the virus used to vaccinate against smallpox. Antiviral antibody responses remained stable between 1-75 years after vaccination, whereas antiviral T-cell responses declined slowly, with a half-life of 8-15 years. If these levels of immunity are considered to be at least partially protective, then the morbidity and mortality associated with an intentional smallpox outbreak would be substantially reduced because of pre-existing immunity in a large number of previously vaccinated individuals.
Asunto(s)
Memoria Inmunológica , Vacuna contra Viruela/inmunología , Linfocitos T/inmunología , Adulto , Anciano , Formación de Anticuerpos , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/inmunología , Estudios Transversales , Femenino , Semivida , Humanos , Inmunización Secundaria , Masculino , Persona de Mediana Edad , Vacuna contra Viruela/uso terapéutico , Linfocitos T/virología , Factores de Tiempo , Virus Vaccinia/inmunologíaRESUMEN
Monkeypox virus (MPV) is a virulent human pathogen that has gained increased attention because of its potential use as a bioterrorism agent and inadvertent introduction into North America in 2003. The US outbreak also provided an important opportunity to study MPV-specific T cell immunity. Although MPV-specific CD4(+) and CD8(+) T cells could recognize vaccinia virus (VV)-infected monocytes and produce inflammatory cytokines such as IFNgamma and TNFalpha, they were largely incapable of responding to autologous MPV-infected cells. Further analysis revealed that, unlike cowpox virus (CPV), MPV did not interfere with MHC expression or intracellular transport of MHC molecules. Instead, MPV-infected cells were capable of preventing T cell receptor (TcR)-mediated T cell activation in trans. The ability to trigger a state of nonresponsiveness represents a unique MHC-independent mechanism for blocking antiviral T cell activation and inflammatory cytokine production and is likely an important attribute involved with viral dissemination in the infected host.
Asunto(s)
Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/inmunología , Activación de Linfocitos/inmunología , Monkeypox virus/inmunología , Mpox/inmunología , Presentación de Antígeno/inmunología , Complejo CD3/inmunología , Linfocitos T CD4-Positivos/virología , Linfocitos T CD8-positivos/virología , Infecciones por Virus de Epstein-Barr/inmunología , Regulación de la Expresión Génica , Genes MHC Clase I/genética , Genes MHC Clase II/genética , Herpesvirus Humano 4/inmunología , Humanos , Leucocitos Mononucleares/inmunología , Leucocitos Mononucleares/virología , Vaccinia/inmunología , Virus Vaccinia/inmunología , Replicación ViralRESUMEN
The durability of immune responses to smallpox vaccine is a subject of considerable debate. We compared cutaneous vaccinia responses in patients vaccinated in the distant past with vaccine-naïve individuals using serial close-up photographs. The previously vaccinated group had a significantly reduced time course and milder cutaneous reactions. Vaccinated individuals appear to maintain clinically detectable immunity against vaccinia for at least 20 years after smallpox vaccination.
Asunto(s)
Piel/patología , Vaccinia/patología , Formación de Anticuerpos , Humanos , Inmunidad , Registros Médicos , Fotograbar , Viruela/inmunología , Viruela/prevención & control , Vacuna contra Viruela/uso terapéutico , Factores de Tiempo , VacunaciónRESUMEN
Pre-existing serum antibodies play an important role in vaccine-mediated protection against infection but the underlying mechanisms of immune memory are unclear. Clinical studies indicate that antigen-specific antibody responses can be maintained for many years, leading to theories that reactivation/differentiation of memory B cells into plasma cells is required to sustain long-term antibody production. Here, we present a decade-long study in which we demonstrate site-specific survival of bone marrow-derived plasma cells and durable antibody responses to multiple virus and vaccine antigens in rhesus macaques for years after sustained memory B cell depletion. Moreover, BrdU+ cells with plasma cell morphology can be detected for 10 years after vaccination/BrdU administration, indicating that plasma cells may persist for a prolonged period of time in the absence of cell division. On the basis of these results, long-lived plasma cells represent a key cell population responsible for long-term antibody production and serological memory.
Asunto(s)
Linfocitos B/inmunología , Memoria Inmunológica , Células Plasmáticas/inmunología , Animales , Anticuerpos Antibacterianos/inmunología , Formación de Anticuerpos , Vacunas Bacterianas/administración & dosificación , Vacunas Bacterianas/inmunología , Supervivencia Celular , Macaca mulatta , Masculino , Células Plasmáticas/citología , VacunaciónRESUMEN
West Nile virus (WNV) is a mosquito-transmitted pathogen with a wide geographical range that can lead to long-term disability and death in some cases. Despite the public health risk posed by WNV, including an estimated 3 million infections in the United States alone, no vaccine is available for use in humans. Here, we present a scaled manufacturing approach for production of a hydrogen peroxide-inactivated whole virion WNV vaccine, termed HydroVax-001WNV. Vaccination resulted in robust virus-specific neutralizing antibody responses and protection against WNV-associated mortality in mice or viremia in rhesus macaques (RM). A GLP-compliant toxicology study performed in rats demonstrated an excellent safety profile with clinical findings limited to minor and transient irritation at the injection site. An in vitro relative potency (IVRP) assay was developed and shown to correlate with in vivo responses following forced degradation studies. Long-term in vivo potency comparisons between the intended storage condition (2-8°C) and a thermally stressed condition (40±2°C) demonstrated no loss in vaccine efficacy or protective immunity over a 6-month span of time. Together, the positive pre-clinical findings regarding immunogenicity, safety, and stability indicate that HydroVax-001WNV is a promising vaccine candidate.
Asunto(s)
Fiebre del Nilo Occidental/prevención & control , Vacunas contra el Virus del Nilo Occidental/inmunología , Animales , Antiinfecciosos Locales/metabolismo , Anticuerpos Neutralizantes/sangre , Anticuerpos Antivirales/sangre , Modelos Animales de Enfermedad , Evaluación Preclínica de Medicamentos , Estabilidad de Medicamentos , Efectos Colaterales y Reacciones Adversas Relacionados con Medicamentos/patología , Femenino , Calor , Peróxido de Hidrógeno/metabolismo , Macaca mulatta , Masculino , Ratones Endogámicos BALB C , Ratas Sprague-Dawley , Análisis de Supervivencia , Estados Unidos , Potencia de la Vacuna , Vacunas de Productos Inactivados/administración & dosificación , Vacunas de Productos Inactivados/efectos adversos , Vacunas de Productos Inactivados/inmunología , Vacunas de Productos Inactivados/aislamiento & purificación , Viremia/prevención & control , Vacunas contra el Virus del Nilo Occidental/administración & dosificación , Vacunas contra el Virus del Nilo Occidental/efectos adversos , Vacunas contra el Virus del Nilo Occidental/aislamiento & purificaciónRESUMEN
Infection with yellow fever virus (YFV), an explosively replicating flavivirus, results in viral hemorrhagic disease characterized by cardiovascular shock and multi-organ failure. Unvaccinated populations experience 20 to 50% fatality. Few studies have examined the pathophysiological changes that occur in humans during YFV infection due to the sporadic nature and remote locations of outbreaks. Rhesus macaques are highly susceptible to YFV infection, providing a robust animal model to investigate host-pathogen interactions. In this study, we characterized disease progression as well as alterations in immune system homeostasis, cytokine production and gene expression in rhesus macaques infected with the virulent YFV strain DakH1279 (YFV-DakH1279). Following infection, YFV-DakH1279 replicated to high titers resulting in viscerotropic disease with â¼72% mortality. Data presented in this manuscript demonstrate for the first time that lethal YFV infection results in profound lymphopenia that precedes the hallmark changes in liver enzymes and that although tissue damage was noted in liver, kidneys, and lymphoid tissues, viral antigen was only detected in the liver. These observations suggest that additional tissue damage could be due to indirect effects of viral replication. Indeed, circulating levels of several cytokines peaked shortly before euthanasia. Our study also includes the first description of YFV-DakH1279-induced changes in gene expression within peripheral blood mononuclear cells 3 days post-infection prior to any clinical signs. These data show that infection with wild type YFV-DakH1279 or live-attenuated vaccine strain YFV-17D, resulted in 765 and 46 differentially expressed genes (DEGs), respectively. DEGs detected after YFV-17D infection were mostly associated with innate immunity, whereas YFV-DakH1279 infection resulted in dysregulation of genes associated with the development of immune response, ion metabolism, and apoptosis. Therefore, WT-YFV infection is associated with significant changes in gene expression that are detectable before the onset of clinical symptoms and may influence disease progression and outcome of infection.
Asunto(s)
Interacciones Huésped-Patógeno , Transcriptoma/fisiología , Fiebre Amarilla/fisiopatología , Virus de la Fiebre Amarilla/fisiología , Animales , Antígenos Virales/inmunología , Modelos Animales de Enfermedad , Progresión de la Enfermedad , Femenino , Regulación Viral de la Expresión Génica , Humanos , Riñón/patología , Leucocitos Mononucleares/inmunología , Hígado/inmunología , Hígado/patología , Linfopenia/virología , Macaca mulatta , Insuficiencia Multiorgánica/virología , Necrosis , Bazo/patología , Vacunas Atenuadas/inmunología , Fiebre Amarilla/inmunología , Fiebre Amarilla/virología , Vacuna contra la Fiebre Amarilla/inmunología , Virus de la Fiebre Amarilla/inmunologíaRESUMEN
Although smallpox has been eradicated, other diseases caused by virulent orthopoxviruses such as monkeypox virus (MPV) remain endemic in remote areas of western and central sub-Saharan Africa, and represent a potential biothreat due to international travel and/or inadvertent exposure. Unfortunately, extensive antigenic cross-reactivity among orthopoxviruses presents a challenge to serological diagnosis. We previously reported a 20mer peptide-based ELISA that identified recent MPV infection with >90% sensitivity and >90% specificity. However, the sensitivity of this approach was not determined with samples obtained at later time points after antibody titers had declined from their peak levels. To improve assay sensitivity for detecting MPV-specific antibodies at later time points, we compared diagnostic 20mer peptides to 30mer peptides. In addition, optimal 30mer peptides were tested in combination or after conjugating selected peptides to a carrier protein (bovine serum albumin) to further improve assay performance. An optimized combination of four unconjugated 30mer peptides provided 100% sensitivity for detecting MPV infection at 2-6 months post-infection, 45% sensitivity for detecting MPV infection at >2 years post-infection, and 99% specificity. However, an optimized combination of two peptide conjugates provided 100% sensitivity for detecting MPV infection at 2-6 months post-infection, 90% sensitivity for detecting MPV infection at >2 years post-infection, and 97% specificity. Peptide-based ELISA tests provide a relatively simple approach for serological detection of MPV infection. Moreover, the systematic approach used here to optimize diagnostic peptide reagents is applicable to developing improved diagnostics to a broad range of other viruses, and may be particularly useful for distinguishing between closely-related viruses within the same genus or family.
Asunto(s)
Ensayo de Inmunoadsorción Enzimática/métodos , Mpox/diagnóstico , Proteínas Virales/aislamiento & purificación , Adulto , Secuencia de Aminoácidos , Brotes de Enfermedades , Humanos , Mpox/sangre , Mpox/epidemiología , Monkeypox virus/aislamiento & purificación , Estudios Retrospectivos , Sensibilidad y Especificidad , Albúmina Sérica Bovina , Proteínas Virales/química , Wisconsin/epidemiologíaRESUMEN
Once established, serum antibody responses against a specific pathogen may last a lifetime. We describe a cohort of four subjects who received smallpox vaccination, and a single subject who received multiple vaccinations, with antibody levels to unrelated antigens monitored for 1-3 years. These immunizations provided the opportunity to determine if infection/vaccination and the resulting toll-like receptor stimulation would alter antigen-specific serological memory to other antigens, including bacterial toxins (tetanus, diphtheria, and pertussis) and viruses (yellow fever virus, measles, mumps, rubella, Epstein-Barr virus, and varicella-zoster virus). Our results indicate that serum IgG levels are remarkably stable and infection or vaccination are unlikely to increase or decrease pre-existing antigen-specific antibody responses.