RESUMO
Mayaro virus (MAYV) is an emerging arbovirus member of the Togaviridae family and Alphavirus genus. MAYV infection causes an acute febrile illness accompanied by persistent polyarthralgia and myalgia. Understanding the mechanisms involved in arthritis caused by alphaviruses is necessary to develop specific therapies. In this work, we investigated the role of the CCL2/CCR2 axis in the pathogenesis of MAYV-induced disease. For this, wild-type (WT) C57BL/6J and CCR2-/- mice were infected with MAYV subcutaneously and evaluated for disease development. MAYV infection induced an acute inflammatory disease in WT mice. The immune response profile was characterized by an increase in the production of inflammatory mediators, such as IL-6, TNF, and CCL2. Higher levels of CCL2 at the local and systemic levels were followed by the significant recruitment of CCR2+ macrophages and a cellular response orchestrated by these cells. CCR2-/- mice showed an increase in CXCL-1 levels, followed by a replacement of the macrophage inflammatory infiltrate by neutrophils. Additionally, the absence of the CCR2 receptor protected mice from bone loss induced by MAYV. Accordingly, the silencing of CCL2 chemokine expression in vivo and the pharmacological blockade of CCR2 promoted a partial improvement in disease. Cell culture data support the mechanism underlying the bone pathology of MAYV, in which MAYV infection promotes a pro-osteoclastogenic microenvironment mediated by CCL2, IL-6, and TNF, which induces the migration and differentiation of osteoclast precursor cells. Overall, these data contribute to the understanding of the pathophysiology of MAYV infection and the identification future of specific therapeutic targets in MAYV-induced disease.IMPORTANCEThis work demonstrates the role of the CCL2/CCR2 axis in MAYV-induced disease. The infection of wild-type (WT) C57BL/6J and CCR2-/- mice was associated with high levels of CCL2, an important chemoattractant involved in the recruitment of macrophages, the main precursor of osteoclasts. In the absence of the CCR2 receptor, there is a mitigation of macrophage migration to the target organs of infection and protection of these mice against bone loss induced by MAYV infection. Much evidence has shown that host immune response factors contribute significantly to the tissue damage associated with alphavirus infections. Thus, this work highlights molecular and cellular targets involved in the pathogenesis of arthritis triggered by MAYV and identifies novel therapeutic possibilities directed to the host inflammatory response unleashed by MAYV.
Assuntos
Infecções por Alphavirus , Artrite , Quimiocina CCL2 , Receptores CCR2 , Animais , Camundongos , Alphavirus , Infecções por Alphavirus/imunologia , Artrite/imunologia , Artrite/virologia , Quimiocina CCL2/imunologia , Interleucina-6/imunologia , Camundongos Endogâmicos C57BL , Receptores CCR2/imunologia , Camundongos Knockout , Masculino , Doenças Ósseas/virologiaRESUMO
Eastern equine encephalitis virus (EEEV), western equine encephalitis virus (WEEV) and Venezuelan equine encephalitis virus (VEEV) can cause fatal encephalitis in humans and equids. Some MAbs to the E1 glycoprotein are known to be cross-reactive, weakly neutralizing in vitro but can protect from disease in animal models. We investigated the mechanism of neutralization of VEEV infection by the broadly cross-reactive E1-specific MAb 1A4B-6. 1A4B-6 protected 3-week-old Swiss Webster mice prophylactically from lethal VEEV challenge. Likewise, 1A4B-6 inhibited virus growth in vitro at a pre-attachment step after virions were incubated at 37 °C and inhibited virus-mediated cell fusion. Amino acid residue N100 in the fusion loop of E1 protein was identified as critical for binding. The potential to elicit broadly cross-reactive MAbs with limited virus neutralizing activity in vitro but that can inhibit virus entry and protect animals from infection merits further exploration for vaccine and therapeutic developmental research.
Assuntos
Anticorpos Antivirais/imunologia , Vírus da Encefalite Equina Venezuelana/imunologia , Vírus da Encefalite Equina Venezuelana/metabolismo , Encefalomielite Equina Venezuelana/imunologia , Encefalomielite Equina Venezuelana/virologia , Proteínas do Envelope Viral/imunologia , Replicação Viral/efeitos dos fármacos , Alphavirus/imunologia , Infecções por Alphavirus/imunologia , Sequência de Aminoácidos , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/imunologia , Linhagem Celular , Chlorocebus aethiops , Reações Cruzadas , Encefalomielite Equina Venezuelana/terapia , Glicoproteínas/imunologia , Imunoterapia , Camundongos , Ligação Proteica , Células Vero , Proteínas do Envelope Viral/metabolismo , Vírion/imunologia , Vírion/metabolismoRESUMO
Mayaro virus (MAYV) is an alphavirus endemic to both Latin America and the Caribbean. Recent reports have questioned the ability of MAYV and its close relative, Chikungunya virus (CHIKV), to generate cross-reactive, neutralizing antibodies to one another. Since CHIKV was introduced to South America in 2013, discerning whether individuals have cross-reactive antibodies or whether they have had exposures to both viruses previously has been difficult. Using samples obtained from people infected with MAYV prior to the introduction of CHIKV in the Americas, we performed neutralizing assays and observed no discernable neutralization of CHIKV by sera from patients previously infected with MAYV. These data suggest that a positive CHIKV neutralization test cannot be attributed to prior exposure to MAYV and that previous exposure to MAYV may not be protective against a subsequent CHIKV infection.
Assuntos
Infecções por Alphavirus/diagnóstico , Infecções por Alphavirus/epidemiologia , Anticorpos Neutralizantes/sangue , Anticorpos Antivirais/sangue , Febre de Chikungunya/diagnóstico , Febre de Chikungunya/epidemiologia , Alphavirus/imunologia , Infecções por Alphavirus/imunologia , Infecções por Alphavirus/virologia , Febre de Chikungunya/imunologia , Febre de Chikungunya/virologia , Vírus Chikungunya/imunologia , Reações Cruzadas , Humanos , Soros Imunes/química , Testes de Neutralização , Peru/epidemiologiaRESUMO
Chikungunya virus (CHIKV) and Mayaro virus (MAYV) are closely related members of the Semliki Forest virus antigenic complex classified as belonging to the genus Alphavirus of the family Togaviridae. These viruses cause human disease, with sudden fever and joint inflammation that can persist for long periods. CHIKV is the causative agent of large outbreaks worldwide, and MAYV infection represents a growing public health concern in Latin America, causing sporadic cases and geographically limited outbreaks. Considering the relationship between CHIKV and MAYV, the present study aimed to evaluate if preexisting CHIKV immunity protects against MAYV infection. Immunocompetent C57BL/6 mice were intraperitoneally infected with CHIKV and, 4 weeks later, they were infected with MAYV in their hind paw. We observed that the preexistence of CHIKV immunity conferred partial cross-protection against secondary MAYV infection, reducing disease severity, tissue viral load, and histopathological scores. Interestingly, CHIKV antibodies from humans and mice showed low cross-neutralization to MAYV, but neutralizing activity significantly increased after secondary infection. Furthermore, depletion of adaptive immune cells (CD4+ T, CD8+ T, and CD19+ B cells) did not alter the cross-protection phenotype, suggesting that distinct cell subsets or a combination of adaptive immune cells stimulated by CHIKV are responsible for the partial cross-protection against MAYV. The reduction of proinflammatory cytokines, such as interferon gamma (IFN-γ), in animals secondarily infected by MAYV, suggests a role for innate immunity in cross-protection. Our findings shed light on how preexisting immunity to arthritogenic alphaviruses may affect secondary infection, which may further develop relevant influence in disease outcome and viral transmission. IMPORTANCE Mosquito-borne viruses have a worldwide impact, especially in tropical climates. Chikungunya virus has been present mostly in developing countries, causing millions of infections, while Mayaro virus, a close relative, has been limited to the Caribbean and tropical regions of Latin America. The potential emergence and spread of Mayaro virus to other high-risk areas have increased the scientific community's attention to an imminent worldwide epidemic. Here, we designed an experimental protocol of chikungunya and Mayaro virus mouse infection, which develops a measurable and quantifiable disease that allows us to make inferences about potential immunological effects during secondary virus infection. Our results demonstrate that previous chikungunya virus infection is able to reduce the severity of clinical outcomes during secondary Mayaro infection. We provide scientific understanding of immunological features during secondary infection with the closely related virus, thus assisting in better comprehending viral transmission and the pathological outcome of these diseases.
Assuntos
Infecções por Alphavirus/imunologia , Infecções por Alphavirus/prevenção & controle , Vírus Chikungunya/imunologia , Proteção Cruzada/imunologia , Alphavirus/imunologia , Infecções por Alphavirus/patologia , Animais , Anticorpos Antivirais/imunologia , Febre de Chikungunya/virologia , Modelos Animais de Doenças , Epidemias , Feminino , Inflamação , Camundongos , Camundongos Endogâmicos C57BL , Carga ViralRESUMO
Mayaro virus (MAYV), which causes mayaro fever, is endemic to limited regions of South America that may expand due to the possible involvement of Aedes spp. mosquitoes in its transmission. Its effective control will require the accurate identification of infected individuals, which has been restricted to nucleic acid-based tests due to similarities with other emerging members of the Alphavirus genus of the Togaviridae family; both in structure and clinical symptoms. Serological tests have a more significant potential to expand testing at a reasonable cost, and their performance primarily reflects that of the antigen utilized to capture pathogen-specific antibodies. Here, we describe the assembly of a synthetic gene encoding multiple copies of antigenic determinants mapped from the nsP1, nsP2, E1, and E2 proteins of MAYV that readily expressed as a stable chimeric protein in bacteria. Its serological performance as the target in ELISAs revealed a high accuracy for detecting anti-MAYV IgM antibodies. No cross-reactivity was observed with serum from seropositive individuals for dengue, chikungunya, yellow fever, Zika, and other infectious diseases as well as healthy individuals. Our data suggest that this bioengineered antigen could be used to develop high-performance serological tests for MAYV infections.
Assuntos
Infecções por Alphavirus/diagnóstico , Alphavirus/imunologia , Epitopos/imunologia , Infecções por Togaviridae/diagnóstico , Aedes/virologia , Alphavirus/patogenicidade , Infecções por Alphavirus/imunologia , Infecções por Alphavirus/transmissão , Infecções por Alphavirus/virologia , Animais , Ensaio de Imunoadsorção Enzimática , Epitopos/genética , Epitopos/ultraestrutura , Feminino , Genes Sintéticos/genética , Genes Sintéticos/imunologia , Humanos , Imunoglobulina M/imunologia , Masculino , Testes Sorológicos , América do Sul/epidemiologia , Togaviridae/isolamento & purificação , Togaviridae/patogenicidade , Infecções por Togaviridae/imunologia , Infecções por Togaviridae/transmissão , Infecções por Togaviridae/virologiaRESUMO
Mayaro virus (MAYV) is an emerging arbovirus of the Americas that may cause a debilitating arthritogenic disease. The biology of MAYV is not fully understood and largely inferred from related arthritogenic alphaviruses. Here, we present the structure of MAYV at 4.4 Å resolution, obtained from a preparation of mature, infective virions. MAYV presents typical alphavirus features and organization. Interactions between viral proteins that lead to particle formation are described together with a hydrophobic pocket formed between E1 and E2 spike proteins and conformational epitopes specific of MAYV. We also describe MAYV glycosylation residues in E1 and E2 that may affect MXRA8 host receptor binding, and a molecular "handshake" between MAYV spikes formed by N262 glycosylation in adjacent E2 proteins. The structure of MAYV is suggestive of structural and functional complexity among alphaviruses, which may be targeted for specificity or antiviral activity.
Assuntos
Infecções por Alphavirus/virologia , Alphavirus/ultraestrutura , Microscopia Crioeletrônica , Espectrometria de Massas , Alphavirus/imunologia , Infecções por Alphavirus/imunologia , Animais , Anticorpos Neutralizantes , Chlorocebus aethiops , Glicosilação , Humanos , Imunoglobulinas , Proteínas de Membrana , Células VeroRESUMO
Madariaga virus (MADV) has recently been associated with severe human disease in Panama, where the closely related Venezuelan equine encephalitis virus (VEEV) also circulates. In June 2017, a fatal MADV infection was confirmed in a community of Darien Province. We conducted a cross-sectional outbreak investigation with human and mosquito collections in July 2017, where sera were tested for alphavirus antibodies and viral RNA. In addition, by applying a catalytic, force-of-infection (FOI) statistical model to two serosurveys from Darien Province in 2012 and 2017, we investigated whether endemic or epidemic alphavirus transmission occurred historically. In 2017, MADV and VEEV IgM seroprevalences were 1.6% and 4.4%, respectively; IgG antibody prevalences were MADV: 13.2%, VEEV: 16.8%, Una virus (UNAV): 16.0%, and Mayaro virus: 1.1%. Active viral circulation was not detected. Evidence of MADV and UNAV infection was found near households, raising questions about its vectors and enzootic transmission cycles. Insomnia was associated with MADV and VEEV infections, depression symptoms were associated with MADV, and dizziness with VEEV and UNAV. Force-of-infection analyses suggest endemic alphavirus transmission historically, with recent increased human exposure to MADV and VEEV in Aruza and Mercadeo, respectively. The lack of additional neurological cases suggests that severe MADV and VEEV infections occur only rarely. Our results indicate that over the past five decades, alphavirus infections have occurred at low levels in eastern Panama, but that MADV and VEEV infections have recently increased-potentially during the past decade. Endemic infections and outbreaks of MADV and VEEV appear to differ spatially in some locations of eastern Panama.
Assuntos
Encefalomielite Equina do Leste/epidemiologia , Encefalomielite Equina Venezuelana/epidemiologia , Fazendeiros/estatística & dados numéricos , Adolescente , Adulto , Distribuição por Idade , Idoso , Idoso de 80 Anos ou mais , Alphavirus/imunologia , Infecções por Alphavirus/epidemiologia , Infecções por Alphavirus/imunologia , Infecções por Alphavirus/fisiopatologia , Animais , Anticorpos Antivirais/imunologia , Febre de Chikungunya/epidemiologia , Febre de Chikungunya/imunologia , Febre de Chikungunya/fisiopatologia , Vírus Chikungunya/imunologia , Criança , Pré-Escolar , Estudos Transversais , Depressão/fisiopatologia , Tontura/fisiopatologia , Vírus da Encefalite Equina do Leste/imunologia , Vírus da Encefalite Equina Venezuelana/imunologia , Encefalomielite Equina do Leste/imunologia , Encefalomielite Equina do Leste/fisiopatologia , Encefalomielite Equina Venezuelana/imunologia , Encefalomielite Equina Venezuelana/fisiopatologia , Doenças Endêmicas , Epidemias , Fadiga/fisiopatologia , Feminino , Habitação/estatística & dados numéricos , Humanos , Imunoglobulina G , Imunoglobulina M , Masculino , Pessoa de Meia-Idade , Mosquitos Vetores/virologia , Panamá/epidemiologia , Vírus da Floresta de Semliki/imunologia , Estudos Soroepidemiológicos , Distúrbios do Início e da Manutenção do Sono/fisiopatologia , Adulto JovemRESUMO
Mayaro virus (MAYV), a sylvatic arbovirus belonging to the Togaviridae family and Alphavirus genus, is responsible for an increasing number of outbreaks in several countries of Central and South America. Despite Haemagogus janthinomys being identified as the main vector of MAYV, laboratory studies have already demonstrated the competence of Aedes aegypti to transmit MAYV. It has also been demonstrated that the WolbachiawMel strain is able to impair the replication and transmission of MAYV in Ae. aegypti. In Ae. aegypti, the small interfering RNA (siRNA) pathway is an important antiviral mechanism; however, it remains unclear whether siRNA pathway acts against MAYV infection in Ae. aegypti. The main objective of this study was to determine the contribution of the siRNA pathway in the control of MAYV infection. Thus, we silenced the expression of AGO2, an essential component of the siRNA pathway, by injecting dsRNA-targeting AGO2 (dsAGO2). Our results showed that AGO2 is required to control MAYV replication upon oral infection in Wolbachia-free Ae. aegypti. On the other hand, we found that Wolbachia-induced resistance to MAYV in Ae. aegypti is independent of the siRNA pathway. Our study brought new information regarding the mechanism of viral protection, as well as on Wolbachia mediated interference.
Assuntos
Aedes/microbiologia , Aedes/virologia , Alphavirus/genética , Interferência de RNA , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Wolbachia/fisiologia , Aedes/imunologia , Infecções por Alphavirus/imunologia , Infecções por Alphavirus/virologia , Animais , Feminino , Humanos , Imunidade Inata , Mosquitos Vetores/imunologia , Mosquitos Vetores/microbiologia , Mosquitos Vetores/virologia , Wolbachia/imunologiaRESUMO
Characterizing the circulation of Mayaro virus (MAYV), an emerging arbovirus threat, is essential for risk assessment but challenging due to cross-reactivity with other alphaviruses such as chikungunya virus (CHIKV). Here, we develop an analytical framework to jointly assess MAYV epidemiology and the extent of cross-reactivity with CHIKV from serological data collected throughout French Guiana (N = 2697). We find strong evidence of an important sylvatic cycle for MAYV with most infections occurring near the natural reservoir in rural areas and in individuals more likely to go to the forest (i.e., adult males) and with seroprevalences of up to 18% in some areas. These findings highlight the need to strengthen MAYV surveillance in the region and showcase how modeling can improve interpretation of cross-reacting assays.
Assuntos
Infecções por Alphavirus/epidemiologia , Arbovírus/isolamento & purificação , Vírus Chikungunya/imunologia , Doenças Transmissíveis Emergentes/epidemiologia , Monitoramento Epidemiológico , Adolescente , Adulto , Infecções por Alphavirus/sangue , Infecções por Alphavirus/imunologia , Infecções por Alphavirus/virologia , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Arbovírus/imunologia , Criança , Pré-Escolar , Doenças Transmissíveis Emergentes/sangue , Doenças Transmissíveis Emergentes/imunologia , Doenças Transmissíveis Emergentes/virologia , Reações Cruzadas/imunologia , Estudos Transversais , Feminino , Guiana Francesa/epidemiologia , Humanos , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Lactente , Masculino , Pessoa de Meia-Idade , Saúde da População Rural/estatística & dados numéricos , Estudos Soroepidemiológicos , Adulto JovemRESUMO
Mayaro virus (MAYV) is endemic in South American countries where it is responsible for sporadic outbreaks of acute febrile illness. The hallmark of MAYV infection is a highly debilitating and chronic arthralgia. Although MAYV emergence is a potential threat, there are no specific therapies or licensed vaccine. In this study, we developed a murine model of MAYV infection that emulates many of the most relevant clinical features of the infection in humans and tested a live-attenuated MAYV vaccine candidate (MAYV/IRES). Intraplantar inoculation of a WT strain of MAYV into immunocompetent mice induced persistent hypernociception, transient viral replication in target organs, systemic production of inflammatory cytokines, chemokines and specific humoral IgM and IgG responses. Inoculation of MAYV/IRES in BALB/c mice induced strong specific cellular and humoral responses. Moreover, MAYV/IRES vaccination of immunocompetent and interferon receptor-defective mice resulted in protection from disease induced by the virulent wt MAYV strain. Thus, this study describes a novel model of MAYV infection in immunocompetent mice and highlights the potential role of a live-attenuated MAYV vaccine candidate in host's protection from disease induced by a virulent MAYV strain.