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Prevention of viral escape and increased coverage against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern require therapeutic monoclonal antibodies (mAbs) targeting multiple sites of vulnerability on the coronavirus spike glycoprotein. Here we identify several potent neutralizing antibodies directed against either the N-terminal domain (NTD) or the receptor-binding domain (RBD) of the spike protein. Administered in combinations, these mAbs provided low-dose protection against SARS-CoV-2 infection in the K18-human angiotensin-converting enzyme 2 mouse model, using both neutralization and Fc effector antibody functions. The RBD mAb WRAIR-2125, which targets residue F486 through a unique heavy-chain and light-chain pairing, demonstrated potent neutralizing activity against all major SARS-CoV-2 variants of concern. In combination with NTD and other RBD mAbs, WRAIR-2125 also prevented viral escape. These data demonstrate that NTD/RBD mAb combinations confer potent protection, likely leveraging complementary mechanisms of viral inactivation and clearance.
Assuntos
Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/imunologia , COVID-19/imunologia , SARS-CoV-2/imunologia , Glicoproteína da Espícula de Coronavírus/imunologia , Sequência de Aminoácidos , Animais , Anticorpos Monoclonais/administração & dosagem , Anticorpos Monoclonais/metabolismo , Anticorpos Neutralizantes/química , Anticorpos Neutralizantes/metabolismo , Anticorpos Antivirais/imunologia , Anticorpos Antivirais/metabolismo , Sítios de Ligação/genética , COVID-19/metabolismo , COVID-19/prevenção & controle , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Mapeamento de Epitopos , Epitopos/química , Epitopos/imunologia , Epitopos/metabolismo , Humanos , Camundongos Transgênicos , Testes de Neutralização , Ligação Proteica , Conformação Proteica , SARS-CoV-2/genética , SARS-CoV-2/metabolismo , Homologia de Sequência de Aminoácidos , Glicoproteína da Espícula de Coronavírus/genética , Glicoproteína da Espícula de Coronavírus/metabolismo , Análise de SobrevidaRESUMO
Mucosal-associated invariant T (MAIT) cells are unconventional T cells with innate-like antimicrobial responsiveness. MAIT cells are known for MR1 (MHC class I-related protein 1)-restricted recognition of microbial riboflavin metabolites giving them the capacity to respond to a broad range of microbes. However, recent progress has shown that MAIT cells can also respond to several viral infections in humans and in mouse models, ranging from HIV-1 and hepatitis viruses to influenza virus and SARS-CoV-2, in a primarily cognate Ag-independent manner. Depending on the disease context MAIT cells can provide direct or indirect antiviral protection for the host and may help recruit other immune cells, but they may also in some circumstances amplify inflammation and aggravate immunopathology. Furthermore, chronic viral infections are associated with varying degrees of functional and numerical MAIT cell impairment, suggesting secondary consequences for host defense. In this review, we summarize recent progress and highlight outstanding questions regarding the emerging role of MAIT cells in antiviral immunity.
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COVID-19 , Células T Invariantes Associadas à Mucosa , Camundongos , Animais , Humanos , COVID-19/metabolismo , SARS-CoV-2/metabolismo , Antígenos de Histocompatibilidade Classe I/metabolismo , Antivirais/metabolismo , Antígenos de Histocompatibilidade Menor/metabolismoRESUMO
BACKGROUND: Shorter prophylactic vaccine schedules may offer more rapid protection against Ebola in resource-limited settings. METHODS: This randomized, observer-blind, placebo-controlled, phase 2 trial conducted in five sub-Saharan African countries included people without HIV (PWOH, n = 249) and people living with HIV (PLWH, n = 250). Adult participants received one of two accelerated Ebola vaccine regimens (MVA-BN-Filo, Ad26.ZEBOV administered 14 days apart [n = 79] or Ad26.ZEBOV, MVA-BN-Filo administered 28 days apart [n = 322]) or saline/placebo (n = 98). The primary endpoints were safety (adverse events [AEs]) and immunogenicity (Ebola virus [EBOV] glycoprotein-specific binding antibody responses). Binding antibody responders were defined as participants with a > 2.5-fold increase from baseline or the lower limit of quantification if negative at baseline. RESULTS: The mean age was 33.4 years, 52% of participants were female, and among PLWH, the median (interquartile range) CD4+ cell count was 560.0 (418.0-752.0) cells/µL. AEs were generally mild/moderate with no vaccine-related serious AEs or remarkable safety profile differences by HIV status. At 21 days post-dose 2, EBOV glycoprotein-specific binding antibody response rates in vaccine recipients were 99% for the 14-day regimen (geometric mean concentrations [GMCs]: 5168 enzyme-linked immunosorbent assay units (EU)/mL in PWOH; 2509 EU/mL in PLWH), and 98% for the 28-day regimen (GMCs: 6037 EU/mL in PWOH; 2939 EU/mL in PLWH). At 12 months post-dose 2, GMCs in PWOH and PLWH were 635 and 514 EU/mL, respectively, for the 14-day regimen and 331 and 360 EU/mL, respectively, for the 28-day regimen. CONCLUSIONS: Accelerated 14- and 28-day Ebola vaccine regimens were safe and immunogenic in PWOH and PLWH in Africa. TRIAL REGISTRATION: NCT02598388.
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The monoclonal antibodies (MAbs) NCI05 and NCI09, isolated from a vaccinated macaque that was protected from multiple simian immunodeficiency virus (SIV) challenges, both target an overlapping, conformationally dynamic epitope in SIV envelope variable region 2 (V2). Here, we show that NCI05 recognizes a CH59-like coil/helical epitope, whereas NCI09 recognizes a ß-hairpin linear epitope. In vitro, NCI05 and, to a lesser extent, NCI09 mediate the killing of SIV-infected cells in a CD4-dependent manner. Compared to NCI05, NCI09 mediates higher titers of antibody-dependent cellular cytotoxicity (ADCC) to gp120-coated cells, as well as higher levels of trogocytosis, a monocyte function that contributes to immune evasion. We also found that passive administration of NCI05 or NCI09 to macaques did not affect the risk of SIVmac251 acquisition compared to controls, demonstrating that these anti-V2 antibodies alone are not protective. However, NCI05 but not NCI09 mucosal levels strongly correlated with delayed SIVmac251 acquisition, and functional and structural data suggest that NCI05 targets a transient state of the viral spike apex that is partially opened, compared to its prefusion-closed conformation. IMPORTANCE Studies suggest that the protection against SIV/simian-human immunodeficiency virus (SHIV) acquisition afforded by the SIV/HIV V1 deletion-containing envelope immunogens, delivered by the DNA/ALVAC vaccine platform, requires multiple innate and adaptive host responses. Anti-inflammatory macrophages and tolerogenic dendritic cells (DC-10), together with CD14+ efferocytes, are consistently found to correlate with a vaccine-induced decrease in the risk of SIV/SHIV acquisition. Similarly, V2-specific antibody responses mediating ADCC, Th1 and Th2 cells expressing no or low levels of CCR5, and envelope-specific NKp44+ cells producing interleukin 17 (IL-17) also are reproducible correlates of decreased risk of virus acquisition. We focused on the function and the antiviral potential of two monoclonal antibodies (NCI05 and NCI09) isolated from vaccinated animals that differ in antiviral function in vitro and recognize V2 in a linear (NCI09) or coil/helical (NCI05) conformation. We demonstrate that NCI05, but not NCI09, delays SIVmac251 acquisition, highlighting the complexity of antibody responses to V2.
Assuntos
Anticorpos Monoclonais , Vírus da Imunodeficiência Símia , Proteínas Virais , Vírus da Imunodeficiência Símia/imunologia , Anticorpos Monoclonais/administração & dosagem , Anticorpos Monoclonais/isolamento & purificação , Anticorpos Monoclonais/metabolismo , Proteínas Virais/química , Proteínas Virais/imunologia , Epitopos/imunologia , Síndrome de Imunodeficiência Adquirida dos Símios/imunologia , Síndrome de Imunodeficiência Adquirida dos Símios/prevenção & controle , Estrutura Terciária de Proteína , Modelos Moleculares , Células CHO , Cricetulus , Animais , Macaca/imunologia , Macaca/virologia , Anticorpos Antivirais/sangueRESUMO
Acute HIV-1 infection (AHI) results in the widespread depletion of CD4+ T cells in peripheral blood and gut mucosal tissue. However, the impact on the predominantly CD4+ immunoregulatory invariant natural killer T (iNKT) cells during AHI remains unknown. Here, iNKT cells from peripheral blood and colonic mucosa were investigated during treated and untreated AHI. iNKT cells in blood were activated and rapidly depleted in untreated AHI. At the time of peak HIV-1 viral load, these cells showed the elevated expression of cell death-associated transcripts compared to preinfection. Residual peripheral iNKT cells suffered a diminished responsiveness to in vitro stimulation early into chronic infection. Additionally, HIV-1 DNA, as well as spliced and unspliced viral RNA, were detected in iNKT cells isolated from blood, indicating the active infection of these cells in vivo. The loss of iNKT cells occurred from Fiebig stage III in the colonic mucosa, and these cells were not restored to normal levels after initiation of ART during AHI. CD4+ iNKT cells were depleted faster and more profoundly than conventional CD4+ T cells, and the preferential infection of CD4+ iNKT cells over conventional CD4+ T cells was confirmed by in vitro infection experiments. In vitro data also provided evidence of latent infection in iNKT cells. Strikingly, preinfection levels of peripheral blood CD4+ iNKT cells correlated directly with the peak HIV-1 load. These findings support a model in which iNKT cells are early targets for HIV-1 infection, driving their rapid loss from circulation and colonic mucosa.
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Linfócitos T CD4-Positivos/imunologia , Colo/imunologia , Colo/virologia , Infecções por HIV/imunologia , Mucosa Intestinal/imunologia , Mucosa Intestinal/virologia , Células T Matadoras Naturais/imunologia , Adolescente , Adulto , Progressão da Doença , Feminino , Infecções por HIV/virologia , HIV-1/imunologia , Humanos , Masculino , Pessoa de Meia-Idade , Infecção Persistente/imunologia , Infecção Persistente/virologia , Adulto JovemRESUMO
Emergence of novel variants of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) underscores the need for next-generation vaccines able to elicit broad and durable immunity. Here we report the evaluation of a ferritin nanoparticle vaccine displaying the receptor-binding domain of the SARS-CoV-2 spike protein (RFN) adjuvanted with Army Liposomal Formulation QS-21 (ALFQ). RFN vaccination of macaques using a two-dose regimen resulted in robust, predominantly Th1 CD4+ T cell responses and reciprocal peak mean serum neutralizing antibody titers of 14,000 to 21,000. Rapid control of viral replication was achieved in the upper and lower airways of animals after high-dose SARS-CoV-2 respiratory challenge, with undetectable replication within 4 d in seven of eight animals receiving 50 µg of RFN. Cross-neutralization activity against SARS-CoV-2 variant B.1.351 decreased only approximately twofold relative to WA1/2020. In addition, neutralizing, effector antibody and cellular responses targeted the heterotypic SARS-CoV-1, highlighting the broad immunogenicity of RFN-ALFQ for SARS-CoV-like Sarbecovirus vaccine development.
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Vacinas contra COVID-19/administração & dosagem , COVID-19/virologia , Macaca mulatta/imunologia , Nanopartículas/química , Receptores Virais/metabolismo , SARS-CoV-2/imunologia , Adjuvantes Imunológicos/administração & dosagem , Animais , Anticorpos Neutralizantes/biossíntese , Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/biossíntese , Anticorpos Antivirais/imunologia , COVID-19/prevenção & controle , Vacinas contra COVID-19/imunologia , Ferritinas/química , SARS-CoV-2/metabolismo , Linfócitos T/imunologiaRESUMO
Herpes simplex virus type 1 (HSV-1) infects and persists in most of the human population. Interleukin-15 (IL-15) has an important role in the activation of cell-mediated immune responses and acts in complex with IL-15 receptor alpha (IL-15R-α) through cell surface transpresentation. Here, we have examined the IL-15/IL-15R-α complex response dynamics during HSV-1 infection in human keratinocytes. Surface expression of the IL-15/IL-15R-α complex rapidly increased in response to HSV-1, reaching a peak around 12 h after infection. This response was dependent on detection of viral replication by TLR3, and enhancement of IL15 and IL15RA gene expression. Beyond the peak of expression, levels of IL-15 and IL-15R-α gradually declined, reaching a profound loss of surface expression beyond 24 h of infection. This involved the loss of IL15 and IL15RA transcription. Interestingly, invariant natural killer T (iNKT) cells inhibited the viral interference with IL-15/IL-15R-α complex expression in an IFNγ-dependent manner. These results indicate that rapid upregulation of the IL-15/IL-15R-α complex occurs in HSV-1 infected keratinocytes, and that this response is targeted by viral interference. Shutdown of the IL-15 axis represents a novel mode of HSV-1 immune evasion, which can be inhibited by the host iNKT cell response.
Assuntos
Herpes Simples , Herpesvirus Humano 1 , Células T Matadoras Naturais , Humanos , Evasão da Resposta Imune , Interleucina-15/metabolismo , Subunidade alfa de Receptor de Interleucina-15/metabolismoRESUMO
[This corrects the article DOI: 10.1371/journal.ppat.1009101.].
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Prior immune responses to coronaviruses might affect human SARS-CoV-2 response. We screened 2,565 serum and plasma samples collected from 2013 through early 2020, before the COVID-19 pandemic began, from 2,250 persons in 4 countries in Africa (Kenya, Nigeria, Tanzania, and Uganda) and in Thailand, including persons living with HIV-1. We detected IgG responses to SARS-CoV-2 spike (S) subunit 2 protein in 1.8% of participants. Profiling against 23 coronavirus antigens revealed that responses to S, subunit 2, or subunit 1 proteins were significantly more frequent than responses to the receptor-binding domain, S-Trimer, or nucleocapsid proteins (p<0.0001). We observed similar responses in persons with or without HIV-1. Among all coronavirus antigens tested, SARS-CoV-2, SARS-CoV-1, and Middle East respiratory syndrome coronavirus antibody responses were much higher in participants from Africa than in participants from Thailand (p<0.01). We noted less pronounced differences for endemic coronaviruses. Serosurveys could affect vaccine and monoclonal antibody distribution across global populations.
Assuntos
COVID-19 , Humanos , Anticorpos Monoclonais , Anticorpos Antivirais , Formação de Anticorpos , COVID-19/epidemiologia , Imunoglobulina G , Nigéria , Proteínas do Nucleocapsídeo , Pandemias , SARS-CoV-2 , Glicoproteína da Espícula de Coronavírus , Tailândia/epidemiologia , ÁfricaRESUMO
The RV144 vaccine efficacy clinical trial showed a reduction in HIV-1 infections by 31%. Vaccine efficacy was associated with stronger binding antibody responses to the HIV Envelope (Env) V1V2 region, with decreased efficacy as responses wane. High levels of Ab-dependent cellular cytotoxicity (ADCC) together with low plasma levels of Env-specific IgA also correlated with decreased infection risk. We investigated whether B cell priming from RV144 vaccination impacted functional antibody responses to HIV-1 following infection. Antibody responses were assessed in 37 vaccine and 63 placebo recipients at 6, 12, and 36 months following HIV diagnosis. The magnitude, specificity, dynamics, subclass recognition and distribution of the binding antibody response following infection were different in RV144 vaccine recipients compared to placebo recipients. Vaccine recipients demonstrated increased IgG1 binding specifically to V1V2, as well as increased IgG2 and IgG4 but decreased IgG3 to HIV-1 Env. No difference in IgA binding to HIV-1 Env was detected between the vaccine and placebo recipients following infection. RV144 vaccination limited the development of broadly neutralizing antibodies post-infection, but enhanced Fc-mediated effector functions indicating B cell priming by RV144 vaccination impacted downstream antibody function. However, these functional responses were not associated with clinical markers of disease progression. These data reveal that RV144 vaccination primed B cells towards specific binding and functional antibody responses following HIV-1 infection.
Assuntos
Vacinas contra a AIDS/imunologia , Anticorpos Anti-HIV/imunologia , Infecções por HIV/imunologia , Infecções por HIV/prevenção & controle , Adulto , Formação de Anticorpos/imunologia , Linfócitos B/imunologia , Feminino , Anticorpos Anti-HIV/sangue , HIV-1 , Humanos , Imunoglobulina G/imunologia , Masculino , Pessoa de Meia-Idade , Produtos do Gene env do Vírus da Imunodeficiência Humana/imunologiaRESUMO
To augment HIV-1 pox-protein vaccine immunogenicity using a next generation adjuvant, a prime-boost strategy of recombinant modified vaccinia virus Ankara and multimeric Env gp145 was evaluated in macaques with either aluminum (alum) or a novel liposomal monophosphoryl lipid A (MPLA) formulation adsorbed to alum, ALFA. Binding antibody responses were robust and comparable between arms, while antibody-dependent neutrophil and monocyte phagocytotic responses were greatly enhanced by ALFA. Per-exposure vaccine efficacy against heterologous tier 2 SHIV mucosal challenge was 90% in ALFA-adjuvanted males (P = 0.002), while alum conferred no protection. Half of the ALFA-adjuvanted males remained uninfected after the full challenge series, which spanned seven months after the last vaccination. Antibody-dependent monocyte and neutrophil phagocytic responses both strongly correlated with protection. Significant sex differences in infection risk were observed, with much lower infection rates in females than males. In humans, MPLA-liposome-alum adjuvanted gp120 also increased HIV-1-specific phagocytic responses relative to alum. Thus, next-generation liposome-based adjuvants can drive vaccine elicited antibody effector activity towards potent phagocytic responses in both macaques and humans and these responses correlate with protection. Future protein vaccination strategies aiming to improve functional humoral responses may benefit from such adjuvants.
Assuntos
Adjuvantes Imunológicos/administração & dosagem , Anticorpos Antivirais/imunologia , Formação de Anticorpos/imunologia , Anticorpos Anti-HIV/imunologia , Infecções por HIV/prevenção & controle , Vacinas contra a SAIDS/uso terapêutico , Síndrome de Imunodeficiência Adquirida dos Símios/prevenção & controle , Adolescente , Adulto , Animais , Anticorpos Neutralizantes/imunologia , Método Duplo-Cego , Feminino , Infecções por HIV/imunologia , Infecções por HIV/virologia , HIV-1/efeitos dos fármacos , HIV-1/imunologia , Humanos , Macaca mulatta , Masculino , Pessoa de Meia-Idade , Vacinas contra a SAIDS/imunologia , Síndrome de Imunodeficiência Adquirida dos Símios/imunologia , Síndrome de Imunodeficiência Adquirida dos Símios/virologia , Vírus da Imunodeficiência Símia/efeitos dos fármacos , Vírus da Imunodeficiência Símia/imunologia , Adulto JovemRESUMO
CD4+ T cells subsets have a wide range of important helper and regulatory functions in the immune system. Several studies have specifically suggested that circulating effector CD4+ T cells may play a direct role in control of HIV replication through cytolytic activity or autocrine ß-chemokine production. However, it remains unclear whether effector CD4+ T cells expressing cytolytic molecules and ß-chemokines are present within lymph nodes (LNs), a major site of HIV replication. Here, we report that expression of ß-chemokines and cytolytic molecules are enriched within a CD4+ T cell population with high levels of the T-box transcription factors T-bet and eomesodermin (Eomes). This effector population is predominately found in peripheral blood and is limited in LNs regardless of HIV infection or treatment status. As a result, CD4+ T cells generally lack effector functions in LNs, including cytolytic capacity and IFNγ and ß-chemokine expression, even in HIV elite controllers and during acute/early HIV infection. While we do find the presence of degranulating CD4+ T cells in LNs, these cells do not bear functional or transcriptional effector T cell properties and are inherently poor to form stable immunological synapses compared to their peripheral blood counterparts. We demonstrate that CD4+ T cell cytolytic function, phenotype, and programming in the peripheral blood is dissociated from those characteristics found in lymphoid tissues. Together, these data challenge our current models based on blood and suggest spatially and temporally dissociated mechanisms of viral control in lymphoid tissues.
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Linfócitos T CD4-Positivos/imunologia , Infecções por HIV/imunologia , HIV-1/imunologia , Vigilância Imunológica , Linfonodos/imunologia , Tecido Linfoide/imunologia , Linfócitos T CD4-Positivos/virologia , Estudos de Casos e Controles , Infecções por HIV/virologia , Humanos , Linfonodos/virologia , Tecido Linfoide/virologia , Carga ViralRESUMO
Zika virus (ZIKV) outbreaks pose a massive public health threat in several countries. We have developed an in vivo model to investigate the host-ZIKV interaction in Drosophila We have found that a strain of ZIKV replicates in wild-type flies without reducing their survival ability. We have shown that ZIKV infection triggers RNA interference and that mutating Dicer-2 results in enhanced ZIKV load and increased susceptibility to ZIKV infection. Using a flavivirus-specific Ab, we have found that ZIKV is localized in the gut and fat body cells of the infected wild-type flies and results in their perturbed homeostasis. In addition, Dicer-2 mutants display severely reduced insulin activity, which could contribute toward the increased mortality of these flies. Our work establishes the suitability of Drosophila as the model system to study host-ZIKV dynamics, which is expected to greatly advance our understanding of the molecular and physiological processes that determine the outcome of this disease.
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Modelos Animais de Doenças , Proteínas de Drosophila/imunologia , Interações Hospedeiro-Patógeno/imunologia , RNA Helicases/imunologia , Ribonuclease III/imunologia , Infecção por Zika virus/imunologia , Animais , Drosophila melanogaster/imunologia , Drosophila melanogaster/virologia , Homeostase/imunologiaRESUMO
The V1V2 loop of the Env protein is a major target for HIV-1 vaccine development because in multiple studies antibodies to this region correlated with protection. Although SAPNs expressed in E. coli elicited anti-V1V2 antibodies, the Env protein is heavily glycosylated. In this study the technology has been adapted for expression in mammalian cells. SAPNs containing a V1V2 loop from a B-subtype transmitter/founder virus were expressed in E. coli, ExpiCHO, and Expi293 cells. Independent of the expression host, particles were well-formed. All SAPNs raised high titers of V1V2-specific antibodies, however, SAPNE.coli induced a mainly anti-V1 response, while SAPNExpiCHO and SAPNExpi293 induced a predominantly anti-V2 response. In an ADCP assay, sera from animals immunized with the SAPNExpiCHO or SAPNExpi293 induced a significant increase in phagocytic activity. This novel way of producing SAPNs displaying glycosylated epitopes could increase the antibody titer, functional activity, and shift the immune response towards the desired pathway.
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Infecções por HIV/genética , HIV-1/genética , Imunidade/genética , Nanopartículas/química , Animais , Anticorpos Monoclonais/genética , Anticorpos Monoclonais/imunologia , Anticorpos Neutralizantes/efeitos dos fármacos , Anticorpos Neutralizantes/imunologia , Epitopos/efeitos dos fármacos , Epitopos/imunologia , Escherichia coli/genética , Produtos do Gene env/genética , Produtos do Gene env/imunologia , Infecções por HIV/imunologia , Infecções por HIV/virologia , HIV-1/imunologia , HIV-1/patogenicidade , Humanos , Imunidade/imunologia , ImunizaçãoRESUMO
Innate lymphocytes are selectively enriched in the liver where they have important roles in liver immunology. Murine studies have shown that type I NKT cells can promote liver inflammation, whereas type II NKT cells have an anti-inflammatory role. In humans, type II NKT cells were found to accumulate in the gut during inflammation and IL13Rα2 was proposed as a marker for these cells. In the human liver, less is known about type I and II NKT cells. Here, we studied the phenotype and function of human liver T cells expressing IL13Rα2. We found that IL13Rα2 was expressed by around 1% of liver-resident memory T cells but not on circulating T cells. In support of their innate-like T-cell character, the IL13Rα2+ T cells had higher expression of promyelocytic leukaemia zinc finger (PLZF) compared to IL13Rα2- T cells and possessed the capacity to produce IL-22. However, only a minority of human liver sulfatide-reactive type II NKT cells expressed IL13Rα2. Collectively, these findings suggest that IL13Rα2 identifies tissue-resident intrahepatic T cells with innate characteristics and the capacity to produce IL-22.
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Memória Imunológica/imunologia , Subunidade alfa2 de Receptor de Interleucina-13/metabolismo , Interleucinas/metabolismo , Fígado/imunologia , Células T Matadoras Naturais/imunologia , Proteína com Dedos de Zinco da Leucemia Promielocítica/metabolismo , Biomarcadores/metabolismo , Humanos , Fígado/citologia , Interleucina 22RESUMO
The establishment of latent HIV-1 reservoirs in terminally differentiated cells represents a major impediment to the success of antiretroviral therapies. Notably, macrophages (MÏs) are susceptible to HIV-1 infection and recent evidence suggests that they may be involved in long-term HIV-1 persistence. While the extensive functional heterogeneity seen across the MÏ cell lineage parallels the spectrum of HIV-1 susceptibility reported across these cell subsets, the facets of MÏ HIV-1 resistance and susceptibility remain to be fully defined. Notably, the differentiation of most MÏ subsets depends on signaling through the macrophage colony-stimulating factor receptor (M-CSFR), which in addition to M-CSF, is now known to bind the unrelated interleukin-34 (IL-34) cytokine. The biological need for two M-CSFR ligands awaits full elucidation. Here, we report that MÏs differentiated from human peripheral blood monocytes with IL-34 are substantially more resistant to HIV-1 infection than M-CSF-derived MÏs. Moreover, while both MÏ subsets express comparable surface protein levels of the HIV-1 receptor and co-receptor, CD4 and CCR5 respectively, the IL-34-MÏs express significantly greater levels of pertinent restriction factor genes, potentially accounting for their greater resistance to HIV-1 infection than that observed in M-CSF-MÏs. Together, our findings underline previously unexplored differentiation pathways resulting in HIV-1-susceptible and resistant MÏ subsets and pave the way for further research that may overcome one of the last major hurdles in developing more successful antiretroviral therapy.
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Infecções por HIV/metabolismo , Infecções por HIV/virologia , Interleucinas/metabolismo , Macrófagos/metabolismo , Macrófagos/virologia , Diferenciação Celular/fisiologia , Citocinas/metabolismo , Fator Estimulador de Colônias de Granulócitos e Macrófagos/metabolismo , HIV-1/patogenicidade , Humanos , Monócitos/metabolismo , Monócitos/virologia , Receptor de Fator Estimulador de Colônias de Macrófagos/metabolismoRESUMO
Invariant NKT (iNKT) cells are innate-like T cells that respond rapidly with a broad range of effector functions upon recognition of glycolipid Ags presented by CD1d. HIV-1 carries Nef- and Vpu-dependent mechanisms to interfere with CD1d surface expression, indirectly suggesting a role for iNKT cells in control of HIV-1 infection. In this study, we investigated whether iNKT cells can participate in the innate cell-mediated immune response to HIV-1. Infection of dendritic cells (DCs) with Nef- and Vpu-deficient HIV-1 induced upregulation of CD1d in a TLR7-dependent manner. Infection of DCs caused modulation of enzymes in the sphingolipid pathway and enhanced expression of the endogenous glucosylceramide Ag. Importantly, iNKT cells responded specifically to rare DCs productively infected with Nef- and Vpu-defective HIV-1. Transmitted founder viral isolates differed in their CD1d downregulation capacity, suggesting that diverse strains may be differentially successful in inhibiting this pathway. Furthermore, both iNKT cells and DCs expressing CD1d and HIV receptors resided in the female genital mucosa, a site where HIV-1 transmission occurs. Taken together, these findings suggest that innate iNKT cell sensing of HIV-1 infection in DCs is an early immune detection mechanism, which is independent of priming and adaptive recognition of viral Ag, and is actively targeted by Nef- and Vpu-dependent viral immune evasion mechanisms.
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Apresentação de Antígeno , Células Dendríticas/imunologia , HIV-1/imunologia , Evasão da Resposta Imune , Células T Matadoras Naturais/imunologia , Antígenos CD1d/genética , Antígenos CD1d/imunologia , Células Dendríticas/virologia , Feminino , Produtos do Gene nef/deficiência , Produtos do Gene nef/genética , Produtos do Gene nef/metabolismo , Glucosilceramidas/genética , Glucosilceramidas/imunologia , Células HEK293 , Antígenos HIV/imunologia , Infecções por HIV/imunologia , Infecções por HIV/virologia , HIV-1/genética , Proteínas do Vírus da Imunodeficiência Humana/deficiência , Proteínas do Vírus da Imunodeficiência Humana/genética , Proteínas do Vírus da Imunodeficiência Humana/metabolismo , Humanos , Imunidade Celular , Células Matadoras Naturais/imunologia , Ativação Linfocitária , Receptor 7 Toll-Like/genética , Receptor 7 Toll-Like/imunologia , Proteínas Virais Reguladoras e Acessórias/deficiência , Proteínas Virais Reguladoras e Acessórias/genética , Proteínas Virais Reguladoras e Acessórias/metabolismoRESUMO
Monocyte activation has been identified as a predictor of mortality and morbidity in HIV-1 infection. This study investigated translocated bacterial flagellin as a potential contributor to systemic monocyte activation via Toll-like receptor 5 (TLR5) stimulation.We demonstrated that circulating flagellin correlated to anti-flagellin, which was associated with soluble markers of microbial translocation (LPS, LBP) and monocyte activation (sCD14, sCD163). Flagellin exposure in vitro reduced monocyte TLR5 expression and the magnitude of reduction was correlated to anti-flagellin levels, indicative of previous flagellin exposure. Circulating anti-flagellin and basal TLR5 expression were both associated with basal and flagellin-stimulated monocyte cytokine production, where HIV + and HIV − differed in their cytokine patterns (IL-1ß, IL-6, IL-8).Our results suggest that translocated flagellin contributes to systemic immune activation in HIV-1 infection and reduces monocyte surface TLR5 expression resulting in a hyperactivated state with elevated basal cytokine production and reduced ability to respond to further TLR5 stimulation.
Assuntos
Translocação Bacteriana/imunologia , Flagelina/imunologia , Infecções por HIV/imunologia , Ativação Linfocitária/imunologia , Monócitos/imunologia , Adulto , Feminino , Infecções por HIV/microbiologia , HIV-1/imunologia , Humanos , Interleucinas/imunologia , Lipopolissacarídeos/imunologia , Masculino , Pessoa de Meia-Idade , Monócitos/microbiologia , Receptor 5 Toll-Like/imunologiaRESUMO
Invariant CD1d-restricted NKT (iNKT) cells play important roles in generating protective immune responses against infections. In this study, we have investigated the role of human iNKT cells in HSV-1 infection and their interaction with epidermal keratinocytes. These cells express CD1d and are the primary target of the virus. Keratinocytes loaded with α-galactosyl ceramide (α-GalCer) could stimulate IFN-γ production and CD25 upregulation by iNKT cells. However, both α-GalCer-dependent and cytokine-dependent activation of iNKT cells was impaired after coculture with HSV-1-infected cells. Notably, CD1d downregulation was not observed on infected keratinocytes, which were also found to inhibit TCR-independent iNKT cell activation. Further examination of the cytokine profile of iNKT-keratinocyte cocultures showed inhibition of IFN-γ, IL-5, IL-10, IL-13, and IL-17 secretion but upregulation of IL-4 and TNF-α after the infection. Moreover, cell-to-cell contact between infected keratinocytes and iNKT cells was required for the inhibition of activation, as the cell-free supernatants containing virus did not affect activation. Productive infection of iNKT cells was however not required for the inhibitory effect. After coculture with infected cells, iNKT cells were no longer responsive to further stimulation with α-GalCer-loaded CD1d-expressing cells. We found that exposure to HSV-1-infected cells resulted in impaired TCR signaling downstream of ZAP70. Additionally, infected cells upregulated the expression of the negative T cell regulator, galectin-9; however, blocking experiments indicated that the impairment of iNKT cell responses was independent of galectin-9. Thus, interference with activation of human iNKT cells by HSV-1 may represent a novel immunoevasive strategy used by the virus to avoid immune clearance.