RESUMEN
The malaria-causing parasites have to complete a complex infection cycle in the mosquito vector that also involves attack by the insect's innate immune system, especially at the early stages of midgut infection. However, Anopheles immunity to the late Plasmodium sporogonic stages, such as oocysts, has received little attention as they are considered to be concealed from immune factors due to their location under the midgut basal lamina and for harboring an elaborate cell wall comprising an external layer derived from the basal lamina that confers self-properties to an otherwise foreign structure. Here, we investigated whether Plasmodium berghei oocysts and sporozoites are susceptible to melanization-based immunity in Anopheles gambiae. Silencing of the negative regulator of melanization response, CLIPA14, increased melanization prevalence without significantly increasing the numbers of melanized oocysts, while co-silencing CLIPA14 with CLIPA2, a second negative regulator of melanization, resulted in a significant increase in melanized oocysts and melanization prevalence. Only late-stage oocysts were found to be melanized, suggesting that oocyst rupture was a prerequisite for melanization-based immune attack, presumably due to the loss of the immune-evasive features of their wall. We also found melanized sporozoites inside oocysts and in the hemocoel, suggesting that sporozoites at different maturation stages are susceptible to melanization. Silencing the melanization promoting factors TEP1 and CLIPA28 rescued oocyst melanization in CLIPA2/CLIPA14 co-silenced mosquitoes. Interestingly, silencing of CTL4, that protects early stage ookinetes from melanization, had no effect on oocysts and sporozoites, indicating differential regulation of immunity to early and late sporogonic stages. Similar to previous studies addressing ookinete stage melanization, the melanization of Plasmodium falciparum oocysts was significantly lower than that observed for P. berghei. In summary, our results provide conclusive evidence that late sporogonic malaria parasite stages are susceptible to melanization, and we reveal distinct regulatory mechanisms for ookinete and oocyst melanization.
Asunto(s)
Anopheles , Melaninas , Oocistos , Plasmodium berghei , Esporozoítos , Animales , Anopheles/parasitología , Anopheles/inmunología , Plasmodium berghei/inmunología , Oocistos/metabolismo , Melaninas/metabolismo , Esporozoítos/inmunología , Esporozoítos/metabolismo , Mosquitos Vectores/parasitología , Mosquitos Vectores/inmunología , Proteínas de Insectos/metabolismo , Proteínas de Insectos/genética , Proteínas de Insectos/inmunología , Malaria/inmunología , Malaria/parasitología , Silenciador del Gen , Inmunidad Innata , FemeninoRESUMEN
The Dengue virus (DENV), primarily spread by Aedes aegypti and also by Aedes albopictus in some regions, poses significant global health risks. Alternative techniques are urgently needed because the current control mechanisms are insufficient to reduce the transmission of DENV. Introducing Wolbachia pipientis into Ae. aegypti inhibits DENV transmission, however, the underlying mechanisms are still poorly understood. Innate immune effector upregulation, the regulation of autophagy, and intracellular competition between Wolbachia and DENV for lipids are among the theories for the mechanism of inhibition. Furthermore, mainly three immune pathways Toll, IMD, and JAK/STAT are involved in the host for the suppression of the virus. These pathways are activated by Wolbachia and DENV in the host and are responsible for the upregulation and downregulation of many genes in mosquitoes, which ultimately reduces the titer of the DENV in the host. The functioning of these immune pathways depends upon the Wolbachia, host, and virus interaction. Here, we summarize the current understanding of DENV recognition by the Ae. aegypti's immune system, aiming to create a comprehensive picture of our knowledge. Additionally, we investigated how Wolbachia regulates the activation of multiple genes associated with immune priming for the reduction of DENV.
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Aedes , Virus del Dengue , Dengue , Inmunidad Innata , Mosquitos Vectores , Wolbachia , Aedes/inmunología , Aedes/virología , Aedes/microbiología , Wolbachia/fisiología , Wolbachia/inmunología , Animales , Virus del Dengue/inmunología , Virus del Dengue/fisiología , Dengue/inmunología , Dengue/transmisión , Dengue/virología , Mosquitos Vectores/inmunología , Mosquitos Vectores/virología , Mosquitos Vectores/microbiología , Interacciones Huésped-Patógeno/inmunología , Humanos , Transducción de Señal/inmunologíaRESUMEN
Despite the critical role of the Anopheles innate immune system in defending against Plasmodium infection, there is still limited information about the key immune mechanisms in Anopheles. This review assesses recent findings on the expression characteristics of immune-related genes in Anopheles following exposure to Plasmodium. A literature review, unrestricted by publication date, was conducted to evaluate immune-related gene expression in different organs of Anopheles after Plasmodium infection. Mosquito immune responses in the midgut are essential for reducing parasite populations. Additionally, innate immune responses in the salivary glands and hemocytes circulating in the hemocoel play key roles in defense against the parasite. Transcriptomic analysis of the mosquito's innate immune response to Plasmodium infection provides valuable insights into key immune mechanisms in mosquito defense. A deeper understanding of immune mechanisms in different organs of Anopheles following Plasmodium infection will aid in discovering critical targets for designing novel control strategies.
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Anopheles , Inmunidad Innata , Malaria , Plasmodium , Animales , Anopheles/parasitología , Anopheles/genética , Anopheles/inmunología , Malaria/inmunología , Malaria/parasitología , Plasmodium/inmunología , Plasmodium/genética , Perfilación de la Expresión Génica , Mosquitos Vectores/parasitología , Mosquitos Vectores/genética , Mosquitos Vectores/inmunología , Interacciones Huésped-Parásitos/inmunología , TranscriptomaRESUMEN
The Aedes aegypti mosquito is a vector of many infectious agents, including flaviviruses such as Zika virus. Components of mosquito saliva have pleomorphic effects on the vertebrate host to enhance blood feeding, and these changes also create a favorable niche for pathogen replication and dissemination. Here, we demonstrate that human CD47, which is known to be involved in various immune processes, interacts with a 34-kilodalton mosquito salivary protein named Nest1. Nest1 is up-regulated in blood-fed female A. aegypti and facilitates Zika virus dissemination in human skin explants. Nest1 has a stronger affinity for CD47 than its natural ligand, signal regulatory protein α, competing for binding at the same interface. The interaction between Nest1 with CD47 suppresses phagocytosis by human macrophages and inhibits proinflammatory responses by white blood cells, thereby suppressing antiviral responses in the skin. This interaction elucidates how an arthropod protein alters the human response to promote arbovirus infectivity.
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Aedes , Piel , Virus Zika , Aedes/inmunología , Aedes/virología , Animales , Humanos , Piel/inmunología , Piel/virología , Virus Zika/inmunología , Virus Zika/fisiología , Femenino , Proteínas de Insectos/inmunología , Infección por el Virus Zika/inmunología , Proteínas y Péptidos Salivales/inmunología , Mosquitos Vectores/inmunología , Mosquitos Vectores/virología , Antígeno CD47RESUMEN
The applicability of the specific human IgG antibody response to Anopheles gambiae salivary Gland Protein-6 peptide 1 (gSG6-P1 salivary peptide) as a biomarker able to distinguish the level of exposure to mosquito bites according to seasonal variations has not yet been evaluated in Central African regions. The study aimed to provide the first reliable data on the IgG anti-gSG6-P1 response in rural area in Cameroon according to the dry- and rainy-season. Between May and December 2020, dry blood samples were collected from people living in the Bankeng village in the forest area of the Centre region of Cameroon. Malaria infection was determined by thick-blood smear microscopy and multiplex PCR. The level of IgG anti-gSG6-P1 response, was assessed by enzyme-linked immunosorbent assay. Anopheles density and aggressiveness were assessed using human landing catches. The prevalence of malaria infection remains significantly higher in the rainy season than in the dry season (77.57% vs 61.44%; p = 0.0001). The specific anti-gSG6-P1 IgG response could be detected in individuals exposed to few mosquito bites and showed inter-individual heterogeneity even when living in the same exposure area. In both seasons, the level of anti-gSG6-P1 IgG response was not significantly different between Plasmodium infected and non-infected individuals. Mosquito bites were more aggressive in the rainy season compared to the dry season (human biting rate-HBR of 15.05 b/p/n vs 1.5 b/p/n) where mosquito density was very low. Infected mosquitoes were found only during the rainy season (sporozoite rate = 10.63% and entomological inoculation rate-EIR = 1.42 ib/p/n). The level of IgG anti-gSG6-P1 response was significantly higher in the rainy season and correlated with HBR (p Ë 0.0001). This study highlights the high heterogeneity of individual's exposure to the Anopheles gambiae s.l vector bites depending on the transmission season in the same area. These findings reinforce the usefulness of the anti-gSG6-P1 IgG response as an accurate immunological biomarker for detecting individual exposure to Anopheles gambiae s.l. bites during the low risk period of malaria transmission in rural areas and for the differentiating the level of exposure to mosquitoes.
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Anopheles , Inmunoglobulina G , Mordeduras y Picaduras de Insectos , Proteínas y Péptidos Salivales , Adolescente , Adulto , Animales , Niño , Preescolar , Femenino , Humanos , Masculino , Persona de Mediana Edad , Adulto Joven , Anopheles/parasitología , Anopheles/inmunología , Camerún/epidemiología , Inmunoglobulina G/sangre , Inmunoglobulina G/inmunología , Mordeduras y Picaduras de Insectos/inmunología , Mordeduras y Picaduras de Insectos/epidemiología , Mordeduras y Picaduras de Insectos/sangre , Proteínas de Insectos/inmunología , Malaria/epidemiología , Malaria/inmunología , Malaria/sangre , Malaria/transmisión , Mosquitos Vectores/parasitología , Mosquitos Vectores/inmunología , Población Rural , Proteínas y Péptidos Salivales/inmunología , Estaciones del AñoRESUMEN
The complete lack of yellow fever virus (YFV) in Asia, and the lack of urban YFV transmission in South America, despite the abundance of the peridomestic mosquito vector Aedes (Stegomyia.) aegypti is an enigma. An immunologically naïve population of over 2 billion resides in Asia, with most regions infested with the urban YF vector. One hypothesis for the lack of Asian YF, and absence of urban YF in the Americas for over 80 years, is that prior immunity to related flaviviruses like dengue (DENV) or Zika virus (ZIKV) modulates YFV infection and transmission dynamics. Here we utilized an interferon α/ß receptor knock-out mouse model to determine the role of pre-existing dengue-2 (DENV-2) and Zika virus (ZIKV) immunity in YF virus infection, and to determine mechanisms of cross-protection. We utilized African and Brazilian YF strains and found that DENV-2 and ZIKV immunity significantly suppresses YFV viremia in mice, but may or may not protect relative to disease outcomes. Cross-protection appears to be mediated mainly by humoral immune responses. These studies underscore the importance of re-assessing the risks associated with YF outbreak while accounting for prior immunity from flaviviruses that are endemic.
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Protección Cruzada , Virus del Dengue , Modelos Animales de Enfermedad , Ratones Noqueados , Receptor de Interferón alfa y beta , Fiebre Amarilla , Virus de la Fiebre Amarilla , Infección por el Virus Zika , Virus Zika , Animales , Fiebre Amarilla/inmunología , Fiebre Amarilla/prevención & control , Fiebre Amarilla/virología , Ratones , Protección Cruzada/inmunología , Virus de la Fiebre Amarilla/inmunología , Virus Zika/inmunología , Infección por el Virus Zika/inmunología , Infección por el Virus Zika/prevención & control , Infección por el Virus Zika/virología , Virus del Dengue/inmunología , Receptor de Interferón alfa y beta/genética , Receptor de Interferón alfa y beta/deficiencia , Anticuerpos Antivirales/inmunología , Anticuerpos Antivirales/sangre , Flavivirus/inmunología , Aedes/virología , Aedes/inmunología , Dengue/inmunología , Dengue/prevención & control , Dengue/virología , Femenino , Viremia/inmunología , Mosquitos Vectores/virología , Mosquitos Vectores/inmunología , Infecciones por Flavivirus/inmunología , Infecciones por Flavivirus/prevención & control , Infecciones por Flavivirus/virología , Ratones Endogámicos C57BLRESUMEN
The obligate endosymbiont Wolbachia induces pathogen interference in the primary disease vector Aedes aegypti, facilitating the utilization of Wolbachia-based mosquito control for arbovirus prevention, particularly against dengue virus (DENV). However, the mechanisms underlying Wolbachia-mediated virus blockade have not been fully elucidated. Here, we report that Wolbachia activates the host cytoplasmic miRNA biogenesis pathway to suppress DENV infection. Through the suppression of the long noncoding RNA aae-lnc-2268 by Wolbachia wAlbB, aae-miR-34-3p, a miRNA upregulated by the Wolbachia strains wAlbB and wMelPop, promoted the expression of the antiviral effector defensin and cecropin genes through the Toll pathway regulator MyD88. Notably, anti-DENV resistance induced by Wolbachia can be further enhanced, with the potential to achieve complete virus blockade by increasing the expression of aae-miR-34-3p in Ae. aegypti. Furthermore, the downregulation of aae-miR-34-3p compromised Wolbachia-mediated virus blockade. These findings reveal a novel mechanism by which Wolbachia establishes crosstalk between the cytoplasmic miRNA pathway and the Toll pathway via aae-miR-34-3p to strengthen antiviral immune responses against DENV. Our results will aid in the advancement of Wolbachia for arbovirus control by enhancing its virus-blocking efficiency.
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Aedes , Virus del Dengue , Dengue , MicroARNs , Wolbachia , Wolbachia/fisiología , Aedes/microbiología , Aedes/virología , Aedes/inmunología , Animales , MicroARNs/genética , MicroARNs/metabolismo , Virus del Dengue/inmunología , Dengue/inmunología , Dengue/virología , Receptores Toll-Like/metabolismo , Receptores Toll-Like/inmunología , Mosquitos Vectores/virología , Mosquitos Vectores/microbiología , Mosquitos Vectores/inmunología , Transducción de Señal , ARN Largo no Codificante/genética , ARN Largo no Codificante/inmunología , Inmunidad Innata , SimbiosisRESUMEN
Resistance to clinical malaria takes years to develop even in hyperendemic regions and sterilizing immunity has rarely been observed. To evaluate the maturation of the host response against controlled repeat exposures to P. falciparum (Pf) NF54 strain-infected mosquitoes, we systematically monitored malaria-naïve participants through an initial exposure to uninfected mosquitoes and 4 subsequent homologous exposures to Pf-infected mosquitoes over 21 months (n = 8 males) (ClinicalTrials.gov# NCT03014258). The primary outcome was to determine whether protective immunity against parasite infection develops following repeat CHMI and the secondary outcomes were to track the clinical signs and symptoms of malaria and anti-Pf antibody development following repeat CHMI. After two exposures, time to blood stage patency increases significantly and the number of reported symptoms decreases indicating the development of clinical tolerance. The time to patency correlates positively with both anti-Pf circumsporozoite protein (CSP) IgG and CD8 + CD69+ effector memory T cell levels consistent with partial pre-erythrocytic immunity. IFNγ levels decrease significantly during the participants' second exposure to high blood stage parasitemia and could contribute to the decrease in symptoms. In contrast, CD4-CD8 + T cells expressing CXCR5 and the inhibitory receptor, PD-1, increase significantly after subsequent Pf exposures, possibly dampening the memory response and interfering with the generation of robust sterilizing immunity.
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Malaria Falciparum , Plasmodium falciparum , Proteínas Protozoarias , Humanos , Malaria Falciparum/inmunología , Malaria Falciparum/parasitología , Malaria Falciparum/sangre , Plasmodium falciparum/inmunología , Masculino , Proteínas Protozoarias/inmunología , Animales , Adulto , Anticuerpos Antiprotozoarios/inmunología , Anticuerpos Antiprotozoarios/sangre , Interferón gamma/metabolismo , Interferón gamma/inmunología , Femenino , Inmunoglobulina G/sangre , Inmunoglobulina G/inmunología , Adulto Joven , Linfocitos T CD8-positivos/inmunología , Mosquitos Vectores/parasitología , Mosquitos Vectores/inmunología , Anopheles/parasitologíaRESUMEN
INTRODUCTION: Malaria continues to remain a major global health problem with nearly a quarter of a billion clinical cases and more than 600,000 deaths in 2022. There has been significant progress toward vaccine development, however, poor efficacy of approved vaccines requiring multiple immunizing doses emphasizes the need for continued efforts toward improved vaccines. Progress to date, nonetheless, has provided impetus for malaria elimination. AREAS COVERED: In this review we will focus on diverse immune mechanisms targeting gametocytes in the human host and gametocyte-mediated malaria transmission via the mosquito vector. EXPERT OPINION: To march toward the goal of malaria elimination it will be critical to target the process of malaria transmission by mosquitoes, mediated exclusively by the sexual stages, i.e. male, and female gametocytes, ingested from infected vertebrate host. Studies over several decades have established antigens in the parasite sexual stages developing in the mosquito midgut as attractive targets for the development of transmission blocking vaccines (TBVs). Immune clearance of gametocytes in the vertebrate host can synergize with TBVs and directly aid in maintaining effective transmission reducing immune potential.
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Vacunas contra la Malaria , Malaria , Mosquitos Vectores , Desarrollo de Vacunas , Humanos , Vacunas contra la Malaria/inmunología , Vacunas contra la Malaria/administración & dosificación , Animales , Malaria/prevención & control , Malaria/transmisión , Malaria/inmunología , Malaria/parasitología , Mosquitos Vectores/parasitología , Mosquitos Vectores/inmunología , Plasmodium/inmunologíaRESUMEN
Introduction: Aedes spp. are the most prolific mosquito vectors in the world. Found on every continent, they can effectively transmit various arboviruses, including the dengue virus which continues to cause outbreaks worldwide and is spreading into previously non-endemic areas. The lack of widely available dengue vaccines accentuates the importance of targeted vector control strategies to reduce the dengue burden. High-throughput tools to estimate human-mosquito contact and evaluate vector control interventions are lacking. We propose a novel serological tool that allows rapid screening of human cohorts for exposure to potentially infectious mosquitoes. Methods: We tested 563 serum samples from a longitudinal pediatric cohort study previously conducted in Cambodia. Children enrolled in the study were dengue-naive at baseline and were followed biannually for dengue incidence for two years. We used Western blotting and enzyme-linked immunosorbent assays to identify immunogenic Aedes aegypti salivary proteins and measure total anti-Ae. aegypti IgG. Results: We found a correlation (rs=0.86) between IgG responses against AeD7L1 and AeD7L2 recombinant proteins and those to whole salivary gland homogenate. We observed seasonal fluctuations of AeD7L1+2 IgG responses and no cross-reactivity with Culex quinquefasciatus and Anopheles dirus mosquitoes. The baseline median AeD7L1+2 IgG responses for young children were higher in those who developed asymptomatic versus symptomatic dengue. Discussion: The IgG response against AeD7L1+2 recombinant proteins is a highly sensitive and Aedes specific marker of human exposure to Aedes bites that can facilitate standardization of future serosurveys and epidemiological studies by its ability to provide a robust estimation of human-mosquito contact in a high-throughput fashion.
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Aedes , Dengue , Proteínas de Insectos , Mosquitos Vectores , Proteínas y Péptidos Salivales , Humanos , Aedes/inmunología , Aedes/virología , Animales , Proteínas y Péptidos Salivales/inmunología , Niño , Mosquitos Vectores/inmunología , Mosquitos Vectores/virología , Dengue/inmunología , Dengue/transmisión , Proteínas de Insectos/inmunología , Femenino , Preescolar , Inmunoglobulina G/inmunología , Inmunoglobulina G/sangre , Masculino , Cambodia , Estudios Longitudinales , Virus del Dengue/inmunología , Adolescente , Mordeduras y Picaduras de Insectos/inmunologíaRESUMEN
The World Health Organization recently declared a global initiative to control arboviral diseases. These are mainly caused by pathogenic flaviviruses (such as dengue, yellow fever and Zika viruses) and alphaviruses (such as chikungunya and Venezuelan equine encephalitis viruses). Vaccines represent key interventions for these viruses, with licensed human and/or veterinary vaccines being available for several members of both genera. However, a hurdle for the licensing of new vaccines is the epidemic nature of many arboviruses, which presents logistical challenges for phase III efficacy trials. Furthermore, our ability to predict or measure the post-vaccination immune responses that are sufficient for subclinical outcomes post-infection is limited. Given that arboviruses are also subject to control by the immune system of their insect vectors, several approaches are now emerging that aim to augment antiviral immunity in mosquitoes, including Wolbachia infection, transgenic mosquitoes, insect-specific viruses and paratransgenesis. In this Review, we discuss recent advances, current challenges and future prospects in exploiting both vertebrate and invertebrate immune systems for the control of flaviviral and alphaviral diseases.
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Infecciones por Arbovirus , Arbovirus , Animales , Humanos , Arbovirus/inmunología , Infecciones por Arbovirus/inmunología , Infecciones por Arbovirus/prevención & control , Vertebrados/inmunología , Vacunas Virales/inmunología , Invertebrados/inmunología , Mosquitos Vectores/inmunología , Mosquitos Vectores/virologíaRESUMEN
Wolbachia, a maternally transmitted symbiotic bacterium of insects, can suppress a variety of human pathogens in mosquitoes, including malaria-causing Plasmodium in the Anopheles vector. However, the mechanistic basis of Wolbachia-mediated Plasmodium suppression in mosquitoes is not well understood. In this study, we compared the midgut and carcass transcriptomes of stably infected Anopheles stephensi with Wolbachia wAlbB to uninfected mosquitoes in order to discover Wolbachia infection-responsive immune genes that may play a role in Wolbachia-mediated anti-Plasmodium activity. We show that wAlbB infection upregulates 10 putative immune genes and downregulates 14 in midguts, while it upregulates 31 putative immune genes and downregulates 15 in carcasses at 24 h after blood-fed feeding, the time at which the Plasmodium ookinetes are traversing the midgut tissue. Only a few of these regulated immune genes were also significantly differentially expressed between Wolbachia-infected and non-infected midguts and carcasses of sugar-fed mosquitoes. Silencing of the Wolbachia infection-responsive immune genes TEP 4, TEP 15, lysozyme C2, CLIPB2, CLIPB4, PGRP-LD and two novel genes (a peritrophin-44-like gene and a macro domain-encoding gene) resulted in a significantly greater permissiveness to P. falciparum infection. These results indicate that Wolbachia infection modulates mosquito immunity and other processes that are likely to decrease Anopheles permissiveness to Plasmodium infection.
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Anopheles , Malaria Falciparum , Plasmodium falciparum , Wolbachia , Animales , Anopheles/parasitología , Anopheles/microbiología , Anopheles/inmunología , Wolbachia/inmunología , Plasmodium falciparum/inmunología , Malaria Falciparum/inmunología , Malaria Falciparum/parasitología , Mosquitos Vectores/parasitología , Mosquitos Vectores/microbiología , Mosquitos Vectores/inmunología , Proteínas de Insectos/genética , Proteínas de Insectos/metabolismo , Proteínas de Insectos/inmunología , Transcriptoma , FemeninoRESUMEN
Malaria is caused when Plasmodium sporozoites are injected along with saliva by an anopheline mosquito into the dermis of a vertebrate host. Arthropod saliva has pleiotropic effects that can influence local host responses, pathogen transmission, and exacerbation of the disease. A mass spectrometry screen identified mosquito salivary proteins that are associated with Plasmodium sporozoites during saliva secretions. In this study, we demonstrate that one of these salivary antigens, Anopheles gambiae sporozoite-associated protein (AgSAP), interacts directly with Plasmodium falciparum and Plasmodium berghei sporozoites. AgSAP binds to heparan sulfate and inhibits local inflammatory responses in the skin. The silencing of AgSAP in mosquitoes reduces their ability to effectively transmit sporozoites to mice. Moreover, immunization with AgSAP decreases the Plasmodium burden in mice that are bitten by Plasmodium-infected mosquitoes. These data suggest that AgSAP facilitates early Plasmodium infection in the vertebrate host and serves as a target for the prevention of malaria. IMPORTANCE Malaria is a vector-borne disease caused by Plasmodium sporozoites. When an anopheline mosquito bites its host, it releases Plasmodium sporozoites as well as saliva components. Mosquito proteins have the potential to serve as antigens to prevent or influence malaria without directly targeting the pathogen. This may help set a new paradigm for vaccine development. In this study, we have elucidated the role of a novel salivary antigen, named Anopheles gambiae sporozoite-associated protein (AgSAP). The results presented here show that AgSAP interacts with Plasmodium falciparum and Plasmodium berghei sporozoites and modulates local inflammatory responses in the skin. Furthermore, our results show that AgSAP is a novel mosquito salivary antigen that influences the early stages of Plasmodium infection in the vertebrate host. Individuals living in countries where malaria is endemic generate antibodies against AgSAP, which indicates that AgSAP can serve as a biomarker for disease prevalence and epidemiological analysis.
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Anopheles/inmunología , Proteínas de Insectos/inmunología , Malaria/parasitología , Mosquitos Vectores/inmunología , Plasmodium berghei/fisiología , Plasmodium falciparum/fisiología , Proteínas y Péptidos Salivales/inmunología , Animales , Anopheles/genética , Anopheles/parasitología , Femenino , Humanos , Proteínas de Insectos/genética , Malaria/inmunología , Malaria/transmisión , Ratones , Ratones Endogámicos C57BL , Mosquitos Vectores/genética , Mosquitos Vectores/parasitología , Plasmodium berghei/genética , Plasmodium falciparum/genética , Proteínas y Péptidos Salivales/genética , Esporozoítos/genética , Esporozoítos/fisiologíaRESUMEN
Dengue, caused by the dengue virus (DENV) is a significant vector-borne disease. In absence of a specific treatment and vaccine, dengue is becoming a rising threat to public health. Currently, control of dengue mainly focuses on the surveillance of the mosquito vectors. Improved surveillance methods for DENV in mosquito populations would be highly beneficial to the public health. However, current methods of DENV detection in mosquitoes requires specialized equipment and expensive reagents and highly trained personnel. As an alternative, commercially available dengue NS1 antigen ELISA kits could be used for detection of DENV infection in Aedes aegypti mosquitoes. In this study, we explored the utility of commercially available Dengue NS1 antigen kit (J. Mitra & Co. Pvt. Ltd) for the detection of recombinant dengue virus-2 (rDENV-2) NS1 protein and serum of dengue infected patient spiked with Ae. aegypti mosquito pools. The kit was found to be highly sensitive and specific towards detection of all serotypes of DENV. Further, it could detect as low as 750 femto gram rDENV-2 NS1 protein. It was also observed that rDENV-2 NS1 antigen spiked with blood-fed and unfed mosquito pools could be detected. In addition, the kit also detected dengue infected patient serum spiked with Ae. aegypti mosquito pools. Overall, the Dengue NS1 antigen kit displayed high sensitivity towards detection of recombinant as well as serum NS1 protein spiked with Ae. aegypti mosquito pools and could be considered for the dengue virus surveillance after a field evaluation in Ae. aegypti mosquitoes.
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Aedes/virología , Antígenos Virales/inmunología , Virus del Dengue/inmunología , Ensayo de Inmunoadsorción Enzimática/métodos , Mosquitos Vectores/virología , Proteínas no Estructurales Virales/inmunología , Aedes/inmunología , Animales , Dengue/diagnóstico , Dengue/inmunología , Dengue/transmisión , Dengue/virología , Virus del Dengue/clasificación , Ensayo de Inmunoadsorción Enzimática/normas , Humanos , Mosquitos Vectores/inmunología , Juego de Reactivos para Diagnóstico , Sensibilidad y Especificidad , SerogrupoRESUMEN
Background: Entomological surveillance for malaria is inherently resource-intensive and produces crude population-level measures of vector exposure which are insensitive in low-transmission settings. Antibodies against Anopheles salivary proteins measured at the individual level may serve as proxy biomarkers for vector exposure and malaria transmission, but their relationship is yet to be quantified. Methods: A systematic review of studies measuring antibodies against Anopheles salivary antigens (PROSPERO: CRD42020185449). Multilevel modelling (to account for multiple study-specific observations [level 1], nested within study [level 2], and study nested within country [level 3]) estimated associations between seroprevalence with Anopheles human biting rate (HBR) and malaria transmission measures. Results: From 3981 studies identified in literature searches, 42 studies across 16 countries were included contributing 393 study-specific observations of anti-Anopheles salivary antibodies determined in 42,764 samples. A positive association between HBR (log transformed) and seroprevalence was found; overall a twofold (100% relative) increase in HBR was associated with a 23% increase in odds of seropositivity (OR: 1.23, 95% CI: 1.10-1.37; p<0.001). The association between HBR and Anopheles salivary antibodies was strongest with concordant, rather than discordant, Anopheles species. Seroprevalence was also significantly positively associated with established epidemiological measures of malaria transmission: entomological inoculation rate, Plasmodium spp. prevalence, and malarial endemicity class. Conclusions: Anopheles salivary antibody biomarkers can serve as a proxy measure for HBR and malaria transmission, and could monitor malaria receptivity of a population to sustain malaria transmission. Validation of Anopheles species-specific biomarkers is important given the global heterogeneity in the distribution of Anopheles species. Salivary biomarkers have the potential to transform surveillance by replacing impractical, inaccurate entomological investigations, especially in areas progressing towards malaria elimination. Funding: Australian National Health and Medical Research Council, Wellcome Trust.
Asunto(s)
Anopheles/inmunología , Antígenos de Protozoos/inmunología , Proteínas de Insectos/inmunología , Malaria/transmisión , Proteínas y Péptidos Salivales/inmunología , Animales , Anticuerpos Antiprotozoarios/inmunología , Australia , Biomarcadores , Humanos , Inmunoglobulina G/inmunología , Mordeduras y Picaduras de Insectos , Malaria/epidemiología , Malaria/inmunología , Modelos Teóricos , Mosquitos Vectores/inmunología , Plasmodium falciparum/inmunología , Estudios SeroepidemiológicosRESUMEN
Mosquito-borne viruses of the Flavivirus genus (Flaviviridae family) pose an ongoing threat to global public health. For example, dengue, Japanese encephalitis, West Nile, yellow fever, and Zika viruses are transmitted by infected mosquitoes and cause severe and fatal diseases in humans. The means by which mosquito-borne flaviviruses establish persistent infection in mosquitoes and cause disease in humans are complex and depend upon a myriad of virus-host interactions, such as those of the innate immune system, which are the main focus of our review. This review also covers the different strategies utilized by mosquito-borne flaviviruses to antagonize the innate immune response in humans and mosquitoes. Given the lack of antiviral therapeutics for mosquito-borne flaviviruses, improving our understanding of these virus-immune interactions could lead to new antiviral therapies and strategies for developing refractory vectors incapable of transmitting these viruses, and can also provide insights into determinants of viral tropism that influence virus emergence into new species.
Asunto(s)
Culicidae/inmunología , Infecciones por Flavivirus/inmunología , Infecciones por Flavivirus/veterinaria , Flavivirus/inmunología , Infección Persistente/inmunología , Infección Persistente/veterinaria , Animales , Culicidae/fisiología , Culicidae/virología , Flavivirus/genética , Flavivirus/fisiología , Infecciones por Flavivirus/transmisión , Infecciones por Flavivirus/virología , Humanos , Inmunidad Innata , Mosquitos Vectores/inmunología , Mosquitos Vectores/fisiología , Mosquitos Vectores/virología , Infección Persistente/virologíaRESUMEN
BACKGROUND: A number of zoonotic mosquito-borne viruses have emerged in Europe in recent decades. Batai virus (BATV), a member of the genus Orthobunyavirus, is one example of a relatively newly emerged mosquito-borne virus, having been detected in mosquitoes and livestock. We conducted vector competency studies on three mosquito species at a low temperature to assess whether Aedes and Culex mosquito species are susceptible to infection with BATV. METHODS: Colonised lines of Aedes aegypti and Culex pipiens and a wild-caught species, Aedes detritus, were orally inoculated with BATV strain 53.2, originally isolated from mosquitoes trapped in Germany in 2009. Groups of blood-fed female mosquitoes were maintained at 20 °C for 7 or 14 days. Individual mosquitoes were screened for the presence of BATV in body, leg and saliva samples for evidence of infection, dissemination and transmission, respectively. BATV RNA was detected by reverse transcription-PCR, and positive results confirmed by virus isolation in Vero cells. RESULTS: Aedes detritus was highly susceptible to BATV, with an infection prevalence of ≥ 80% at both measurement time points. Disseminated infections were recorded in 30.7-41.6% of Ae. detritus, and evidence of virus transmission with BATV in saliva samples (n = 1, days post-infection: 14) was observed. Relatively lower rates of infection for Ae. aegypti and Cx. pipiens were observed, with no evidence of virus dissemination or transmission at either time point. CONCLUSIONS: This study shows that Ae. detritus may be a competent vector for BATV at 20 °C, whereas Ae. aegypti and Cx. pipiens were not competent. Critically, the extrinsic incubation period appears to be ≤ 7 days for Ae. detritus, which may increase the onward transmissibility potential of BATV in these populations.
Asunto(s)
Virus Bunyamwera/fisiología , Culicidae/virología , Mosquitos Vectores/virología , Animales , Virus Bunyamwera/genética , Infecciones por Bunyaviridae/transmisión , Infecciones por Bunyaviridae/virología , Culicidae/inmunología , Europa (Continente) , Femenino , Humanos , Masculino , Mosquitos Vectores/inmunología , Saliva/virologíaRESUMEN
Microbial control of mosquitoes via the use of symbiotic or pathogenic microbes, such as Wolbachia and entomopathogenic fungi, are promising alternatives to synthetic insecticides to tackle the rapid increase in insecticide resistance and vector-borne disease outbreaks. This study evaluated the susceptibility and host responses of two important mosquito vectors, Ae. albopictus and Cx. pipiens, that naturally carry Wolbachia, to infections by entomopathogenic fungi. Our study indicated that while Wolbachia presence did not provide a protective advantage against entomopathogenic fungal infection, it nevertheless influenced the bacterial / fungal load and the expression of select anti-microbial effectors and phenoloxidase cascade genes in mosquitoes. Furthermore, although host responses from Ae. albopictus and Cx. pipiens were mostly similar, we observed contrasting phenotypes with regards to susceptibility and immune responses to fungal entomopathogenic infection in these two mosquitoes. This study provides new insights into the intricate multipartite interaction between the mosquito host, its native symbiont and pathogenic microbes that might be employed to control mosquito populations.
Asunto(s)
Aedes/inmunología , Culex/inmunología , Inmunidad/genética , Mosquitos Vectores/inmunología , Wolbachia/genética , Aedes/efectos de los fármacos , Aedes/genética , Aedes/microbiología , Animales , Culex/efectos de los fármacos , Culex/genética , Culex/microbiología , Hongos , Expresión Génica , Resistencia a los Insecticidas , Insecticidas , Monofenol Monooxigenasa/genética , Monofenol Monooxigenasa/metabolismo , Mosquitos Vectores/microbiología , Simbiosis , Enfermedades Transmitidas por VectoresRESUMEN
Lipid-derived signaling molecules known as eicosanoids have integral roles in mediating immune and inflammatory processes across metazoans. This includes the function of prostaglandins and their cognate G protein-coupled receptors (GPCRs) to employ their immunological actions. In insects, prostaglandins have been implicated in the regulation of both cellular and humoral immune responses, yet in arthropods of medical importance, studies have been limited. Here, we describe a prostaglandin E2 receptor (AgPGE2R) in the mosquito Anopheles gambiae and demonstrate that its expression is most abundant in oenocytoid immune cell populations. Through the administration of prostaglandin E2 (PGE2) and AgPGE2R-silencing, we demonstrate that prostaglandin E2 signaling regulates a subset of prophenoloxidases (PPOs) and antimicrobial peptides (AMPs) that are strongly expressed in populations of oenocytoids. We demonstrate that PGE2 signaling via the AgPGE2R significantly limits both bacterial replication and Plasmodium oocyst survival. Additional experiments establish that PGE2 treatment increases phenoloxidase (PO) activity through the increased expression of PPO1 and PPO3, genes essential to anti-Plasmodium immune responses that promote oocyst killing. We also provide evidence that the mechanisms of PGE2 signaling are concentration-dependent, where high concentrations of PGE2 promote oenocytoid lysis, negating the protective effects of lower concentrations of PGE2 on anti-Plasmodium immunity. Taken together, our results provide new insights into the role of PGE2 signaling on immune cell function and its contributions to mosquito innate immunity that promote pathogen killing.
Asunto(s)
Anopheles/inmunología , Anopheles/microbiología , Anopheles/parasitología , Dinoprostona/metabolismo , Oocistos/inmunología , Plasmodium/inmunología , Transducción de Señal , Animales , Anopheles/clasificación , Hemocitos/metabolismo , Interacciones Huésped-Patógeno/inmunología , Inmunidad Innata , Viabilidad Microbiana , Mosquitos Vectores/inmunología , Mosquitos Vectores/microbiología , Mosquitos Vectores/parasitología , Filogenia , Plasmodium/crecimiento & desarrollo , Proteínas Citotóxicas Formadoras de Poros/metabolismo , Receptores de Prostaglandina E/genética , Receptores de Prostaglandina E/metabolismoRESUMEN
Mosquito immune cells, known as hemocytes, are integral to cellular and humoral responses that limit pathogen survival and mediate immune priming. However, without reliable cell markers and genetic tools, studies of mosquito immune cells have been limited to morphological observations, leaving several aspects of their biology uncharacterized. Here, we use single-cell RNA sequencing (scRNA-seq) to characterize mosquito immune cells, demonstrating an increased complexity to previously defined prohemocyte, oenocytoid, and granulocyte subtypes. Through functional assays relying on phagocytosis, phagocyte depletion, and RNA-FISH experiments, we define markers to accurately distinguish immune cell subtypes and provide evidence for immune cell maturation and differentiation. In addition, gene-silencing experiments demonstrate the importance of lozenge in defining the mosquito oenocytoid cell fate. Together, our scRNA-seq analysis provides an important foundation for future studies of mosquito immune cell biology and a valuable resource for comparative invertebrate immunology.