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Alzheimer's disease (AD) is linked to toxic Aß plaques in the brain and activation of innate responses. Recent findings however suggest that the disease may also depend on the adaptive immunity, as B cells exacerbate and CD8+ T cells limit AD-like pathology in mouse models of amyloidosis. Here, by artificially blocking or augmenting CD8+ T cells in the brain of 5xFAD mice, we provide evidence that AD-like pathology is promoted by pathogenic, proinflammatory cytokines and exhaustion markers expressing CXCR6+ CD39+CD73+/- CD8+ TRM-like cells. The CD8+ T cells appear to act by targeting disease associated microglia (DAM), as we find them in tight complexes with microglia around Aß plaques in the brain of mice and humans with AD. We also report that these CD8+ T cells are induced by B cells in the periphery, further underscoring the pathogenic importance of the adaptive immunity in AD. We propose that CD8+ T cells and B cells should be considered as therapeutic targets for control of AD, as their ablation at the onset of AD is sufficient to decrease CD8+ T cells in the brain and block the amyloidosis-linked neurodegeneration.
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Expression of human endogenous retrovirus type W (HERV-W) has been linked to cancer, making HERV-W antigens potential targets for therapeutic cancer vaccines. In a previous study, we effectively treated established tumours in mice by using adenoviral-vectored vaccines targeting the murine endogenous retrovirus envelope and group-specific antigen (Gag) of melanoma-associated retrovirus (MelARV) in combination with anti-PD-1. To break the immunological tolerance to MelARV, we mutated the immunosuppressive domain (ISD) of the MelARV envelope. However, reports on the immunogenicity of the HERV-W envelope, Syncytin-1, and its ISD are conflicting. To identify the most effective HERV-W cancer vaccine candidate, we evaluated the immunogenicity of vaccines encoding either the wild-type or mutated HERV-W envelope ISD in vitro and in vivo. Here, we show that the wild-type HERV-W vaccine generated higher activation of murine antigen-presenting cells and higher specific T-cell responses than the ISD-mutated counterpart. We also found that the wild-type HERV-W vaccine was sufficient to increase the probability of survival in mice subjected to HERV-W envelope-expressing tumours compared to a control vaccine. These findings provide the foundation for developing a therapeutic cancer vaccine targeting HERV-W-positive cancers in humans.
Assuntos
Vacinas Anticâncer , Retrovirus Endógenos , Neoplasias , Humanos , Animais , Camundongos , Retrovirus Endógenos/genética , Linfócitos T , Terapia de ImunossupressãoRESUMO
Extrinsic factors, such as lifestyle and diet, are shown to be essential in the control of human healthy aging, and thus, longevity. They do so by targeting at least in part the gut microbiome, a collection of commensal microorganisms (microbiota), which colonize the intestinal tract starting after birth, and is established by the age of three. The composition and abundance of individual microbiota appears to continue to change until adulthood, presumably reflecting lifestyle and geographic, racial, and individual differences. Although most of these changes appear to be harmless, a major shift in their composition in the gut (dysbiosis) can trigger harmful local and systemic inflammation. Recent reports indicate that dysbiosis is increased in aging and that the gut microbiota of elderly people is enriched in pro-inflammatory commensals at the expense of beneficial microbes. The clinical consequence of this change remains confusing due to contradictory reports and a high degree of variability of human microbiota and methodologies used. Here, we present the authors' thoughts that underscore dysbiosis as a primary cause of aging-associated morbidities, and thus, premature death of elderly people. We provide evidence that the dysbiosis triggers a chain of pathological and inflammatory events. Examples include alteration of levels of microbiota-affected metabolites, impaired function and integrity of the gastrointestinal tract, and increased gut leakiness. All of these enhance systemic inflammation, which when associated with aging is termed inflammaging, and result in consequent aging-associated pathologies.
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Cancer is a major challenge in our societies, according to the World Health Organization (WHO) about 1/6 deaths were cancer related in 2018 and it is considered the second leading cause of death globally. Immunotherapies have changed the paradigm of oncologic treatment for several cancers where the field had fallen short in providing competent therapies. Despite the improvement, broadly acting and highly effective therapies capable of eliminating or preventing human cancers with insufficient mutated antigens are still missing. Adenoviral vector-based vaccines are a successful tool in the treatment of various diseases including cancer; however, their success has been limited. In this review we discuss the potential of adenovirus as therapeutic tools and the current developments to use them against cancer. More specifically, we examine how to use them to target endogenous retroviruses (ERVs). ERVs, comprising 8% of the human genome, have been detected in several cancers, while they remain silent in healthy tissues. Their low immunogenicity together with their immunosuppressive capacity aid cancer to escape immunosurveillance. In that regard, virus-like-vaccine (VLV) technology, combining adenoviral vectors and virus-like-particles (VLPs), can be ideal to target ERVs and elicit B-cell responses, as well as CD8+ and CD4+ T-cells responses.
Assuntos
Adenoviridae/imunologia , Retrovirus Endógenos/imunologia , Neoplasias/imunologia , Neoplasias/virologia , Vacinas contra Adenovirus/imunologia , Animais , Vetores Genéticos/imunologia , Humanos , Imunidade/imunologia , Imunoterapia/métodos , Vacinas Virais/imunologiaRESUMO
Human endogenous retrovirus type W (HERV-W) is expressed in various cancers. We previously developed an adenovirus-vectored cancer vaccine targeting HERV-W by encoding an assembled HERV-W group-specific antigen sequence and the HERV-W envelope sequence Syncytin-1. Syncytin-1 is constitutively fusogenic and forms large multinucleated cell fusions when overexpressed. Consequently, immunising humans with a vaccine encoding Syncytin-1 can lead to the formation of extensive syncytia, which is undesirable and poses a potential safety issue. Here, we show experiments in cell lines that restoring an evolutionary lost cleavage site of the fusion inhibitory R-peptide of Syncytin-1 inhibit cell fusion. Interestingly, this modification of the HERV-W vaccine's fusogenicity increased the expression of the vaccine antigens in vitro. It also enhanced Syncytin-1-specific antibody responses and CD8+-mediated T-cell responses compared to the wildtype vaccine in vaccinated mice, with a notable enhancement in responses to subdominant T-cell epitopes but equal responses to dominant epitopes and similar rates of survival following a tumour challenge. The impairment of cell-cell fusion and the enhanced immunogenicity profile of this HERV-W vaccine strengthens the prospects of obtaining a meaningful immune response against HERV-W in patients with HERV-W-overexpressing cancers.
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Vacinas Anticâncer , Retrovirus Endógenos , Proteínas da Gravidez , Humanos , Animais , Camundongos , Aminoácidos , Retrovirus Endógenos/genética , Epitopos de Linfócito TRESUMO
Endogenous retroviruses (ERVs) account for 8% of our genome, and, although they are usually silent in healthy tissues, they become reactivated and expressed in pathological conditions such as cancer. Several studies support a functional role of ERVs in tumour development and progression, specifically through their envelope (Env) protein, which contains a region described as an immunosuppressive domain (ISD). We have previously shown that targeting of the murine ERV (MelARV) Env using virus-like vaccine (VLV) technology, consisting of an adenoviral vector encoding virus-like particles (VLPs), induces protection against small tumours in mice. Here, we investigate the potency and efficacy of a novel MelARV VLV with a mutated ISD (ISDmut) that can modify the properties of the adenoviral vaccine-encoded Env protein. We show that the modification of the vaccine's ISD significantly enhanced T-cell immunogenicity in both prime and prime-boost vaccination regimens. The modified VLV in combination with an α-PD1 checkpoint inhibitor (CPI) exhibited excellent curative efficacy against large established colorectal CT26 tumours in mice. Furthermore, only ISDmut-vaccinated mice that survived CT26 challenge were additionally protected against rechallenge with a triple-negative breast cancer cell line (4T1), showing that our modified VLV provides cross-protection against different tumour types expressing ERV-derived antigens. We envision that translating these findings and technology into human ERVs (HERVs) could provide new treatment opportunities for cancer patients with unmet medical needs.
Assuntos
Retrovirus Endógenos , Neoplasias , Vacinas Virais , Animais , Humanos , Camundongos , Retrovirus Endógenos/genética , Vetores Genéticos/genética , Neoplasias/prevenção & controle , Neoplasias/genética , Linfócitos T , Vacinas Virais/genética , Receptor de Morte Celular Programada 1/imunologiaRESUMO
We have recently reported that some cancers induce accumulation of bone marrow (BM) B-cell precursors in the spleen to convert them into metastasis-promoting, immunosuppressive B cells. Here, using various murine tumor models and samples from humans with breast and ovarian cancers, we provide evidence that cancers also co-opt differentiation of these B-cell precursors to generate macrophage-like cells (termed B-MF). We link the transdifferentiation to a small subset of CSF1R+ Pax5Low cells within BM pre-B and immature B cells responding to cancer-secreted M-CSF with downregulation of the transcription factor Pax5 via CSF1R signaling. Although the primary source of tumor-associated macrophages is monocytes, B-MFs are phenotypically and functionally distinguishable. Compared to monocyte-derived macrophages, B-MFs more efficiently phagocytize apoptotic cells, suppress proliferation of T cells and induce FoxP3+ regulatory T cells. In mouse tumor models, B-MFs promote shrinkage of the tumor-infiltrating IFNγ+ CD4 T cell pool and increase cancer progression and metastasis, suggesting that this cancer-induced transdifferentiation pathway is functionally relevant and hence could serve as an immunotherapeutic target.
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Macrófagos , Neoplasias , Animais , Linfócitos B , Diferenciação Celular , Humanos , Camundongos , MonócitosRESUMO
The function of B cells in Alzheimer's disease (AD) is not fully understood. While immunoglobulins that target amyloid beta (Aß) may interfere with plaque formation and hence progression of the disease, B cells may contribute beyond merely producing immunoglobulins. Here we show that AD is associated with accumulation of activated B cells in circulation, and with infiltration of B cells into the brain parenchyma, resulting in immunoglobulin deposits around Aß plaques. Using three different murine transgenic models, we provide counterintuitive evidence that the AD progression requires B cells. Despite expression of the AD-fostering transgenes, the loss of B cells alone is sufficient to reduce Aß plaque burden and disease-associated microglia. It reverses behavioral and memory deficits and restores TGFß+ microglia, respectively. Moreover, therapeutic depletion of B cells at the onset of the disease retards AD progression in mice, suggesting that targeting B cells may also benefit AD patients.
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Doença de Alzheimer/imunologia , Doença de Alzheimer/patologia , Linfócitos B/imunologia , Progressão da Doença , Depleção Linfocítica , Peptídeos beta-Amiloides/metabolismo , Animais , Feminino , Hipocampo/patologia , Humanos , Interleucina-1beta/metabolismo , Ativação Linfocitária/imunologia , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Microglia/metabolismo , Fenótipo , Placa Amiloide/metabolismo , Fator de Crescimento Transformador beta/metabolismoRESUMO
Cancer incidence increases with age and is a leading cause of death. Caloric restriction (CR) confers benefits on health and survival and delays cancer. However, due to CR's stringency, dietary alternatives offering the same cancer protection have become increasingly attractive. Short cycles of a plant-based diet designed to mimic fasting (FMD) are protective against tumorigenesis without the chronic restriction of calories. Yet, it is unclear whether the fasting time, level of dietary restriction, or nutrient composition is the primary driver behind cancer protection. Using a breast cancer model in mice, we compare the potency of daily CR to that of periodic caloric cycling on FMD or an isocaloric standard laboratory chow against primary tumor growth and metastatic burden. Here, we report that daily CR provides greater protection against tumor growth and metastasis to the lung, which may be in part due to the unique immune signature observed with daily CR.
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Restrição Calórica/métodos , Neoplasias Pulmonares/prevenção & controle , Neoplasias Mamárias Experimentais/dietoterapia , Animais , Linhagem Celular Tumoral , Jejum , Feminino , Neoplasias Pulmonares/secundário , Neoplasias Mamárias Experimentais/imunologia , Neoplasias Mamárias Experimentais/patologia , Camundongos , Carga Tumoral , Microambiente Tumoral/imunologiaRESUMO
CD8+ T cells are known to control infections, but their role in preventing latent infection from establishing has not been thoroughly investigated. We hypothesized that a potent CD8+ T cell response patrolling the mucosal viral entry points could kill the first infected cells and thereby abrogate the infection before latency is established. To investigate this, replication deficient adenovirus serotype 5 vectors encoding murine γ-herpesvirus-68 CD8+ T cell epitopes linkedto the T cell adjuvant Invariant chain, were developed. We show that intranasal vaccination of mice reduces the risk of establishment of latent infection from multiple intranasal ID50 challenges with murine γ-herpesvirus-68 by 81% per exposure at 14â¯days post vaccination. Protection waned over time, but immune responses were extended by heterologous prime-boost vaccination applied simultaneously intramuscularly and intranasally, and animals vaccinated 66â¯days prior to challenge showed a strong trend of long-term protection. Our data provides evidence that CD8+ T cells are able to protect against establishment of latent infection. Although the protective efficacy is difficult to maintain over time, this proof-of-concept study suggests a role for a CD8+ T cell arm in future vaccine strategies against latent human viral infections caused by pathogens such as HIV and multiple herpes virus.
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Adenoviridae/genética , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Infecções por Herpesviridae/imunologia , Infecções por Herpesviridae/prevenção & controle , Herpesviridae/patogenicidade , Animais , Feminino , Citometria de Fluxo , Herpesviridae/imunologia , Camundongos , Camundongos Endogâmicos C57BLRESUMO
Immature B cells in the bone marrow emigrate into the spleen during adult lymphopoiesis. Here, we report that emigration is shifted to earlier B-cell stages in mice with orthotopic breast cancer, spontaneous ovarian cancer, and possibly in human breast carcinoma. Using mouse and human bone marrow aspirates and mouse models challenged with highly metastatic 4T1 breast cancer cells, we demonstrated that this was the result of secretion of thymic stromal lymphopoietin (TSLP) by cancer cells. First, TSLP downregulated surface expression of bone marrow (BM) retention receptors CXCR4 and VLA4 in B-cell precursors, increasing their motility and, presumably, emigration. Then, TSLP supported peripheral survival and proliferation of BM B-cell precursors such as pre-B-like cells. 4T1 cancer cells used the increased pool of circulating pre-B-like cells to generate metastasis-supporting regulatory B cells. As such, the loss of TSLP expression in cancer cells alone or TSLPR deficiency in B cells blocked both accumulation of pre-B-like cells in circulation and cancer metastasis, implying that the pre-B cell-TSLP axis can be an attractive therapeutic target. SIGNIFICANCE: Cancer cells induce premature emigration of B-cell precursors from the bone marrow to generate regulatory B cells.
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Linfócitos B/metabolismo , Medula Óssea/metabolismo , Citocinas/metabolismo , Metástase Neoplásica/patologia , Neoplasias/metabolismo , Neoplasias/patologia , Células Precursoras de Linfócitos B/metabolismo , Animais , Proliferação de Células/fisiologia , Feminino , Humanos , Leucócitos Mononucleares/metabolismo , Linfopoese/fisiologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Baço/metabolismo , Linfopoietina do Estroma do TimoRESUMO
The human adenovirus type 19a/64 (hAd19a) is a rare serotype in the human population that transduces human dendritic cells (DCs) and human muscle cells more efficiently than the well-characterized human adenovirus type 5 (hAd5). To further characterize the potential of this vector as a vaccine we designed replication deficient hAd19a, hAd5 and MVA vectors expressing a papillomavirus (PV) antigen fused to the human MHC class II associated invariant chain T cell adjuvant (hIi) and investigated their immunogenicity in vivo in mice and cynomolgus macaques. We initially showed that the hIi encoded in the hAd5 enhanced PV specific CD8+ T cell responses in mice. The T cell responses induced after hAd19a vaccination was similar to those induced by hAd5 vaccination. The hAd19a induced responses were not reduced in presence of preexisting Ad5 immunity in mice. In macaques both vaccines were equally potent at inducing CD8+ T cells after MVA boost, while the level of CD4+ T cell responses were found to be broader in hAd19a primed animals. These data demonstrate the potential of hAd19a as an alternative vector to hAd5 to elicit potent T cell responses to PV.
Assuntos
Adenovírus Humanos/genética , Adenovírus Humanos/imunologia , Animais , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Feminino , Vetores Genéticos , Humanos , Macaca fascicularis , Camundongos , Vacinas contra Papillomavirus/genética , Sorogrupo , Vacinação/efeitos adversos , Vacinação/métodosRESUMO
Currently available prophylactic vaccines have no therapeutic efficacy for preexisting human papillomavirus (HPVs) infections, do not target all oncogenic HPVs and are insufficient to eliminate the burden of HPV induced cancer. We aim to develop an alternative HPV vaccine which is broadly effective and capable of clearing preexisting infection. In an initial attempt to develop a broadly reactive therapeutic vaccine, we designed a putative papillomavirus (PV) ancestor antigen (circulating sequence derived antigenic sequences E1E2-CDSE1E2) based on the conserved E1 and E2 protein sequences from existing oncogenic HPV strains. This antigen was found to be as related to circulating oncogenic Macaca fascicularis papillomaviruses (MfPVs) as to oncogenic HPVs. The CDSE1E2 antigen was fused to a T-cell adjuvant and encoded in chimpanzee 3 and 63 adenoviral vectors. We first showed that the combination of these 2 vaccines induced long-lasting potent CDSE1E2 specific T cell responses in outbred mice. This prime-boost regimen was then tested in female macaques naturally infected with MfPVs. All immunized animals (16/16) responded to the vaccine antigen but with reduced cross-reactivity against existing PVs. Preexisting MfPV infections did not prime vaccine inducible immune responses. Importantly, immunized oncogenic MfPV type 3 (MfPV3) infected animals that responded toward MfPV3 were able to diminish cervical MfPV3 DNA content. Although insufficient breadth was achieved, our results suggest that a relevant level of E1E2 specific T cell immunity is achievable and might be sufficient for the elimination of PV infection. Importantly, naturally infected macaques, offer a relevant model for testing vaccines aimed at eliminating mucosal PV infections.
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Colo do Útero/imunologia , Vírus Oncogênicos/imunologia , Papillomaviridae/imunologia , Infecções por Papillomavirus/imunologia , Vacinas contra Papillomavirus/imunologia , Linfócitos T/imunologia , Neoplasias do Colo do Útero/prevenção & controle , Animais , Animais não Endogâmicos , Antígenos de Diferenciação de Linfócitos B/genética , Antígenos Virais/genética , Células Cultivadas , Colo do Útero/virologia , DNA Viral/análise , Modelos Animais de Doenças , Feminino , Engenharia Genética , Antígenos de Histocompatibilidade Classe II/genética , Humanos , Imunidade Celular , Imunização Secundária , Macaca fascicularis , Camundongos , Vírus Oncogênicos/genética , Pan troglodytes , Papillomaviridae/genética , Infecções por Papillomavirus/complicações , Proteínas Recombinantes de Fusão/genética , Linfócitos T/virologia , Neoplasias do Colo do Útero/etiologia , Vacinas de DNA , Proteínas Virais/genéticaRESUMO
Conventional HIV T cell vaccine strategies have not been successful in containing acute peak viremia, nor in providing long-term control. We immunized rhesus macaques intramuscularly and rectally using a heterologous adenovirus vectored SIV vaccine regimen encoding normally weakly immunogenic tat, vif, rev and vpr antigens fused to the MHC class II associated invariant chain. Immunizations induced broad T cell responses in all vaccinees. Following up to 10 repeated low-dose intrarectal challenges, vaccinees suppressed early viral replication (P=0.01) and prevented the peak viremia in 5/6 animals. Despite consistently undetectable viremia in 2 out of 6 vaccinees, all animals showed evidence of infection induced immune responses indicating that infection had taken place. Vaccinees, with and without detectable viremia better preserved their rectal CD4+ T cell population and had reduced immune hyperactivation as measured by naïve T cell depletion, Ki-67 and PD-1 expression on T cells. These results indicate that vaccination towards SIV accessory antigens vaccine can provide a level of acute control of SIV replication with a suggestion of beneficial immunological consequences in infected animals of unknown long-term significance. In conclusion, our studies demonstrate that a vaccine encoding subdominant antigens not normally associated with virus control can exert a significant impact on acute peak viremia.
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Antígenos Heterófilos/imunologia , Vetores Genéticos/imunologia , Retrovirus dos Símios/fisiologia , Vacinas contra a SAIDS/imunologia , Adenoviridae/genética , Animais , Antígenos Heterófilos/genética , Antígenos Heterófilos/metabolismo , Linfócitos T CD4-Positivos/citologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/citologia , Linfócitos T CD8-Positivos/imunologia , Vetores Genéticos/genética , Vetores Genéticos/metabolismo , Células HEK293 , Humanos , Macaca mulatta , Camundongos , Viremia/imunologia , Viremia/prevenção & controle , Replicação Viral/fisiologiaRESUMO
Previous studies have shown promising results when using an agonistic anti-4-1BB antibody treatment against established tumors. While this is promising, this type of treatment can induce severe side effects. Therefore, we decided to incorporate the membrane form of 4-1BB ligand (4-1BBL) in a replicative deficient adenovirus vaccine expressing the invariant chain (Ii) adjuvant fused to a tumor associated antigen (TAA). The Ii adjuvant increases and prolongs TAA specific CD8+ T cells as previously shown and local expression of 4-1BBL was chosen to avoid the toxicity associated with systemic antibody administration. Furthermore, adenovirus encoded 4-1BBL expression has previously been successfully used to enhance responses toward Plasmodium falciparum and Influenza A antigens. We showed that the incorporation of 4-1BBL in the adenovirus vector led to surface expression of 4-1BBL on antigen presenting cells, but it did not enhance T cell responses in mice towards the Ii linked antigen. In tumor-bearing mice, our vaccine was found to decrease the frequency of TAA specific CD8+ T cells, but this difference did not alter the therapeutic efficacy. In order to reconcile our findings with the previous reports of increased anti-cancer efficacy using systemically delivered 4-1BB agonists, we incorporated a secreted version of 4-1BBL (Fc-4-1BBL) in our vaccine and co-expressed it with the Ii linked to TAA. In tumor bearing mice, this vaccine initially delayed tumor growth and slightly increased survival compared to the vaccine expressing the membrane form of 4-1BBL. Accordingly, secreted 4-1BBL co-encoded with the Ii linked antigen may offer a simplification compared to administration of drug and vaccine separately.
Assuntos
Ligante 4-1BB/imunologia , Adenoviridae , Adjuvantes Imunológicos/administração & dosagem , Antígenos de Neoplasias/imunologia , Vacinas Anticâncer/imunologia , Melanoma Experimental/terapia , Animais , Células Apresentadoras de Antígenos/imunologia , Antígeno B7-2/metabolismo , Linfócitos T CD8-Positivos/imunologia , Células COS , Feminino , Fibroblastos/metabolismo , Células HEK293 , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Recombinantes/imunologia , Membro 9 da Superfamília de Receptores de Fatores de Necrose Tumoral/metabolismoRESUMO
The low number of envelope (Env) spikes presented on native HIV-1 particles is a major impediment for HIV-1 prophylactic vaccine development. We designed virus-like particle encoding adenoviral vectors utilizing SIVmac239 Gag as an anchor for full length and truncated HIV-1 M consensus Env. Truncated Env overexpressed VRC01 and 17b binding antigen on the surface of transduced cells while the full length Env vaccine presented more and similar amounts of antigen binding to the trimer conformation sensitive antibodies PGT151 and PGT145, respectively. The adenoviral vectors were used to prime Balb/c mice followed by sequential boosting with chimpanzee type 63, and chimpanzee type 3 adenoviral vectors encoding SIVmac239 Gag and full length consensus Env. Both vaccine regimens induced increasing titers of binding antibody responses after each immunization, and significant differences in immune responses between the two groups were observed after the final immunization. Full length Env priming skewed antibody responses towards gp41, while truncated Env priming induced responses primarily targeting gp120 containing and derived antigens. Importantly, no differences in neutralizing antibody responses were found between the different priming regimens as both induced high titered tier 1 neutralizing antibodies, but no tier 2 antibodies, possibly reflecting the similar presentation of trimer specific antibody epitopes. The described vaccine regimens provide insight into the effects of the HIV-1 Env cytoplasmic tail on epitope presentation and subsequent immune responses, which is relevant for the interpretation of current clinical trials that are using truncated Env as an immunogen. The regimens described here provide similar neutralization titers, and thus are useful for investigating the importance of specificity in non-neutralizing antibody mediated protection against viral challenge.
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Vacinas contra a AIDS/imunologia , Adenoviridae/genética , Anticorpos Anti-HIV/sangue , Proteína gp120 do Envelope de HIV/imunologia , HIV-1/imunologia , Vacinas de Partículas Semelhantes a Vírus/imunologia , Produtos do Gene env do Vírus da Imunodeficiência Humana/imunologia , Vacinas contra a AIDS/administração & dosagem , Vacinas contra a AIDS/genética , Adenoviridae/imunologia , Adenovírus Humanos/genética , Adenovírus Humanos/imunologia , Animais , Anticorpos Neutralizantes/sangue , Anticorpos Neutralizantes/imunologia , Epitopos/imunologia , Genes gag , Vetores Genéticos , Anticorpos Anti-HIV/imunologia , Imunidade Humoral , Imunogenicidade da Vacina , Camundongos Endogâmicos BALB C , Vírus da Imunodeficiência Símia/genética , Vírus da Imunodeficiência Símia/imunologiaRESUMO
In this study, we compared adenoviral vaccine vectors with the capacity to induce equally potent immune responses against non-dominant and immunodominant epitopes of murine lymphocytic choriomeningitis virus (LCMV). Our results demonstrate that vaccination targeting non-dominant epitopes facilitates potent virus-induced T-cell responses against immunodominant epitopes during subsequent challenge with highly invasive virus. In contrast, when an immunodominant epitope was included in the vaccine, the T-cell response associated with viral challenge remained focussed on that epitope. Early after challenge with live virus, the CD8+ T cells specific for vaccine-encoded epitopes, displayed a phenotype typically associated with prolonged/persistent antigenic stimulation marked by high levels of KLRG-1, as compared to T cells reacting to epitopes not included in the vaccine. Notably, this association was lost over time in T cells specific for the dominant T cell epitopes, and these cells were fully capable of expanding in response to a new viral challenge. Overall, our data suggests a potential for broadening of the antiviral CD8+ T-cell response by selecting non-dominant antigens to be targeted by vaccination. In addition, our findings suggest that prior adenoviral vaccination is not likely to negatively impact the long-term and protective immune response induced and maintained by a vaccine-attenuated chronic viral infection.
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Antígenos Virais/imunologia , Epitopos de Linfócito T/imunologia , Linfócitos T/imunologia , Vacinas Virais/imunologia , Viroses/imunologia , Adenoviridae/genética , Animais , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Doença Crônica , Modelos Animais de Doenças , Vetores Genéticos/genética , Vetores Genéticos/imunologia , Epitopos Imunodominantes/imunologia , Memória Imunológica , Imunofenotipagem , Coriomeningite Linfocítica/imunologia , Vírus da Coriomeningite Linfocítica/imunologia , Camundongos , Vacinação , Proteínas Virais/imunologia , Viroses/metabolismo , Viroses/prevenção & controleRESUMO
The development of vaccines that target tumor antigens in cancer has proven difficult. A major reason for this is that T cells specific for tumor self-antigens and neoantigens are eliminated or inactivated through mechanisms of tolerance. Antigen fusion strategies which increase the ability of vaccines to stimulate T cells that have escaped tolerance mechanisms, may have a particular potential as immunotherapies. This review highlights antigen fusion strategies that have been successful in stimulating the induction of T-cell immunity against cancer and counteracting tumor-associated tolerance. In preclinical studies, these strategies have shown to improve the potency of vectored vaccines through fusion of tumor antigen to proteins or protein domains that increase CD4+ T-cell help, CD8+ T-cell responses or both the CD4+ and CD8+ T-cell responses. However, in clinical trials such strategies seem to be less efficient when provided as a DNA vaccine. The first clinical trial using a viral vectored fusion-gene vaccine is expected to be tested as a partner in a heterologous prime-boost regimen directed against cervical cancer.