RESUMEN
Chimeric antigen receptor (CAR) T cell therapy has achieved remarkable success in hematological malignancies but remains ineffective in solid tumors, due in part to CAR T cell exhaustion in the solid tumor microenvironment. To study dysfunction of mesothelin-redirected CAR T cells in pancreatic cancer, we establish a robust model of continuous antigen exposure that recapitulates hallmark features of T cell exhaustion and discover, both in vitro and in CAR T cell patients, that CAR dysregulation is associated with a CD8+ T-to-NK-like T cell transition. Furthermore, we identify a gene signature defining CAR and TCR dysregulation and transcription factors, including SOX4 and ID3 as key regulators of CAR T cell exhaustion. Our findings shed light on the plasticity of human CAR T cells and demonstrate that genetic downmodulation of ID3 and SOX4 expression can improve the efficacy of CAR T cell therapy in solid tumors by preventing or delaying CAR T cell dysfunction.
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Linfocitos T CD8-positivos/inmunología , Inmunoterapia Adoptiva/métodos , Neoplasias Pancreáticas/terapia , Receptores Quiméricos de Antígenos/inmunología , Animales , Linfocitos T CD8-positivos/citología , Línea Celular Tumoral , Células HEK293 , Humanos , Proteínas Inhibidoras de la Diferenciación/inmunología , Masculino , Ratones , Ratones Noqueados , Ratones Desnudos , Ratones SCID , Proteínas de Neoplasias/inmunología , Factores de Transcripción SOXC/inmunologíaRESUMEN
BackgroundWe conducted a phase I clinical trial that infused CCR5 gene-edited CD4+ T cells to determine how these T cells can better enable HIV cure strategies.MethodsThe aim of trial was to develop RNA-based approaches to deliver zinc finger nuclease (ZFN), evaluate the effect of CCR5 gene-edited CD4+ T cells on the HIV-specific T cell response, test the ability of infused CCR5 gene-edited T cells to delay viral rebound during analytical treatment interruption, and determine whether individuals heterozygous for CCR5 Δ32 preferentially benefit. We enrolled 14 individuals living with HIV whose viral load was well controlled by antiretroviral therapy (ART). We measured the time to viral rebound after ART withdrawal, the persistence of CCR5-edited CD4+ T cells, and whether infusion of 10 billion CCR5-edited CD4+ T cells augmented the HIV-specific immune response.ResultsInfusion of the CD4+ T cells was well tolerated, with no serious adverse events. We observed a modest delay in the time to viral rebound relative to historical controls; however, 3 of the 14 individuals, 2 of whom were heterozygous for CCR5 Δ32, showed post-viral rebound control of viremia, before ultimately losing control of viral replication. Interestingly, only these individuals had substantial restoration of HIV-specific CD8+ T cell responses. We observed immune escape for 1 of these reinvigorated responses at viral recrudescence, illustrating a direct link between viral control and enhanced CD8+ T cell responses.ConclusionThese findings demonstrate how CCR5 gene-edited CD4+ T cell infusion could aid HIV cure strategies by augmenting preexisting HIV-specific immune responses.REGISTRATIONClinicalTrials.gov NCT02388594.FundingNIH funding (R01AI104400, UM1AI126620, U19AI149680, T32AI007632) was provided by the National Institute of Allergy and Infectious Diseases (NIAID), the National Institute on Drug Abuse (NIDA), the National Institute of Mental Health (NIMH), and the National Institute of Neurological Disorders and Stroke (NINDS). Sangamo Therapeutics also provided funding for these studies.
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Antirretrovirales/administración & dosificación , Linfocitos T CD4-Positivos , Edición Génica , Infecciones por VIH , VIH-1/fisiología , Transfusión de Linfocitos , Receptores CCR5 , Replicación Viral/inmunología , Adulto , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD4-Positivos/trasplante , Linfocitos T CD8-positivos/inmunología , Femenino , Infecciones por VIH/genética , Infecciones por VIH/inmunología , Infecciones por VIH/terapia , Humanos , Masculino , Persona de Mediana Edad , Receptores CCR5/genética , Receptores CCR5/inmunología , Carga Viral/genética , Carga Viral/inmunología , Replicación Viral/efectos de los fármacos , Replicación Viral/genéticaRESUMEN
HIV is adept at avoiding naturally generated T cell responses; therefore, there is a need to develop HIV-specific T cells with greater potency for use in HIV cure strategies. Starting with a CD4-based chimeric antigen receptor (CAR) that was previously used without toxicity in clinical trials, we optimized the vector backbone, promoter, HIV targeting moiety, and transmembrane and signaling domains to determine which components augmented the ability of T cells to control HIV replication. This re-engineered CAR was at least 50-fold more potent in vitro at controlling HIV replication than the original CD4 CAR, or a TCR-based approach, and substantially better than broadly neutralizing antibody-based CARs. A humanized mouse model of HIV infection demonstrated that T cells expressing optimized CARs were superior at expanding in response to antigen, protecting CD4 T cells from infection, and reducing viral loads compared to T cells expressing the original, clinical trial CAR. Moreover, in a humanized mouse model of HIV treatment, CD4 CAR T cells containing the 4-1BB costimulatory domain controlled HIV spread after ART removal better than analogous CAR T cells containing the CD28 costimulatory domain. Together, these data indicate that potent HIV-specific T cells can be generated using improved CAR design and that CAR T cells could be important components of an HIV cure strategy.
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Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/inmunología , Infecciones por VIH/terapia , Infecciones por VIH/virología , VIH-1/fisiología , Recoverina/inmunología , Replicación Viral , Anticuerpos Neutralizantes/inmunología , Infecciones por VIH/inmunología , Humanos , Transducción de Señal/fisiologíaRESUMEN
Based on the success in animal models of type 1 diabetes (T1D), clinical trials of adoptive regulatory T cell (Treg) therapy are underway using ex vivo expanded polyclonal Tregs. However, pre-clinical data also demonstrate that islet-specific Tregs are more potent than polyclonal Tregs at reversing T1D. Translation of this approach into man will require methods to generate large populations of islet-specific Tregs which, to date, has proved to be a major hurdle. Here we demonstrate the feasibility of lentiviral-mediated T cell receptor (TCR) gene transfer to confer antigen specificity on polyclonal human Tregs. Targeting has been achieved using TCRs isolated from human islet-specific and viral-specific CD4+ T cell clones. Engineered T cells demonstrated expression of ectopically-delivered TCRs, resulting in endowment of cognate antigen-specific responses. This enabled antigen-specific suppression at increased potency compared to polyclonal Tregs. However, cells transduced with islet-specific TCRs were less responsive to cognate antigen than viral-specific TCRs, and in some cases, required additional methods to isolate functional antigen-specific Tregs. This study demonstrates the potential of TCR gene transfer to develop islet-specific Treg therapies for effective treatment of T1D, but also highlights that additional optimisation may be required to achieve its full potential.
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Islotes Pancreáticos/inmunología , Receptores de Antígenos de Linfocitos T/genética , Especificidad del Receptor de Antígeno de Linfocitos T/genética , Linfocitos T Reguladores/inmunología , Linfocitos T Reguladores/metabolismo , Animales , Línea Celular , Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 1/inmunología , Diabetes Mellitus Tipo 1/metabolismo , Diabetes Mellitus Tipo 1/terapia , Modelos Animales de Enfermedad , Epítopos de Linfocito T/inmunología , Orden Génico , Técnicas de Transferencia de Gen , Terapia Genética , Vectores Genéticos/genética , Humanos , Células Jurkat , Lentivirus/genética , Ratones , Transducción GenéticaRESUMEN
HIV-1 entry can be inhibited by soluble peptides from the gp41 heptad repeat-2 (HR2) domain that interfere with formation of the 6-helix bundle during fusion. Inhibition has also been seen when these peptides are conjugated to anchoring molecules and over-expressed on the cell surface. We hypothesized that potent anti-HIV activity could be achieved if a 34 amino acid peptide from HR2 (C34) were brought to the site of virus-cell interactions by conjugation to the amino termini of HIV-1 coreceptors CCR5 or CXCR4. C34-conjugated coreceptors were expressed on the surface of T cell lines and primary CD4 T cells, retained the ability to mediate chemotaxis in response to cognate chemokines, and were highly resistant to HIV-1 utilization for entry. Notably, C34-conjugated CCR5 and CXCR4 each exhibited potent and broad inhibition of HIV-1 isolates from diverse clades irrespective of tropism (i.e., each could inhibit R5, X4 and dual-tropic isolates). This inhibition was highly specific and dependent on positioning of the peptide, as HIV-1 infection was poorly inhibited when C34 was conjugated to the amino terminus of CD4. C34-conjugated coreceptors could also inhibit HIV-1 isolates that were resistant to the soluble HR2 peptide inhibitor, enfuvirtide. When introduced into primary cells, CD4 T cells expressing C34-conjugated coreceptors exhibited physiologic responses to T cell activation while inhibiting diverse HIV-1 isolates, and cells containing C34-conjugated CXCR4 expanded during HIV-1 infection in vitro and in a humanized mouse model. Notably, the C34-conjugated peptide exerted greater HIV-1 inhibition when conjugated to CXCR4 than to CCR5. Thus, antiviral effects of HR2 peptides can be specifically directed to the site of viral entry where they provide potent and broad inhibition of HIV-1. This approach to engineer HIV-1 resistance in functional CD4 T cells may provide a novel cell-based therapeutic for controlling HIV infection in humans.
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Linfocitos T CD4-Positivos/virología , Proteína gp41 de Envoltorio del VIH/metabolismo , Infecciones por VIH/metabolismo , VIH-1/metabolismo , Fragmentos de Péptidos/metabolismo , Receptores CXCR4/metabolismo , Internalización del Virus , Animales , Linfocitos T CD4-Positivos/metabolismo , Citometría de Flujo , Células HEK293 , Humanos , Ratones , Ratones Endogámicos NODRESUMEN
In carcinogen-driven cancers, a high mutational burden results in neoepitopes that can be recognized immunologically. Such carcinogen-induced tumors may evade this immune response through "immunoediting," whereby tumors adapt to immune pressure and escape T cell-mediated killing. Many tumors lack a high neoepitope burden, and it remains unclear whether immunoediting occurs in such cases. Here, we evaluated T cell immunity in an autochthonous mouse model of pancreatic cancer and found a low mutational burden, absence of predicted neoepitopes derived from tumor mutations, and resistance to checkpoint immunotherapy. Spontaneous tumor progression was identical in the presence or absence of T cells. Moreover, tumors arising in T cell-depleted mice grew unchecked in immune-competent hosts. However, introduction of the neoantigen ovalbumin (OVA) led to tumor rejection and T cell memory, but this did not occur in OVA immune-tolerant mice. Thus, immunoediting does not occur in this mouse model - a likely consequence, not a cause, of absent neoepitopes. Because many human tumors also have a low missense mutational load and minimal neoepitope burden, our findings have clinical implications for the design of immunotherapy for patients with such tumors.
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Antígenos de Neoplasias/inmunología , Evasión Inmune , Inmunoterapia , Neoplasias Pancreáticas/inmunología , Linfocitos T/inmunología , Animales , Línea Celular Tumoral , Epítopos/inmunología , Femenino , Ratones , Ratones Endogámicos C57BLRESUMEN
Rhesus (rh) but not human (hu) TRIM5α potently restricts human immunodeficiency virus (HIV)-1 infection. It is not clear why huTRIM5α fails to effectively block HIV infection, but it is thought to have a lower affinity for the viral core. Using primary human CD4 T cells, we investigated the ability of huTRIM5α, rhTRIM5α, and the huTRIM5αR323-332 B30.2/SPRY patch-mutant to form cytoplasmic bodies, postulated as key components of the HIV-1 restriction apparatus. Both rhTRIM5α and huTRIM5αR323-332 formed pronounced cytoplasmic bodies, whereas cytoplasmic bodies in T cells overexpressing huTRIM5α were present but more difficult to detect. As expression of all three TRIM5α orthologs was similar at the RNA level, we next investigated the role of protein stability in conferring TRIM5α-mediated HIV-1 restriction. Both steady-state and pulse-chase experiments revealed that the huTRIM5α protein was much less stable than rhTRIM5α, and this difference correlated with higher self-ubiquitination activity. Using a stabilized form of huTRIM5α in which the steady-state expression level was more similar to rhTRIM5α, we observed comparable HIV-1 restriction activity in multi-round HIV-1 challenge assays. Lastly, primary human CD4 T cells expressing a stabilized huTRIM5α were protected from HIV-1-mediated destruction in vivo, indicating that efforts to stabilize huTRIM5α should have significant long-term therapeutic value.
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Linfocitos T CD4-Positivos/metabolismo , Proteínas Portadoras/genética , Proteínas Portadoras/metabolismo , Infecciones por VIH/prevención & control , VIH-1/inmunología , Proteínas/genética , Proteínas/metabolismo , Animales , Factores de Restricción Antivirales , Linfocitos T CD4-Positivos/trasplante , Linfocitos T CD4-Positivos/virología , Células Cultivadas , Citoplasma/metabolismo , Modelos Animales de Enfermedad , Infecciones por VIH/metabolismo , VIH-1/crecimiento & desarrollo , Humanos , Macaca mulatta , Ratones , Estabilidad Proteica , ARN/metabolismo , Proteínas de Motivos Tripartitos , Ubiquitina-Proteína Ligasas , UbiquitinaciónRESUMEN
CCR5, a cell surface molecule critical for the transmission and spread of HIV-1, is dynamically regulated during T cell activation and differentiation. The molecular mechanism linking T cell activation to modulation of CCR5 expression remains undefined. Kruppel-like factor 2 (KLF2) is a transcription factor that promotes quiescence, survival, and in part by modulating chemokine receptor levels, induces homing to secondary lymphoid organs. Given the relationship between T cell activation and chemokine receptor expression, we tested whether the abundance of KLF2 after T cell activation regulates CCR5 expression and, thus, susceptibility of a T cell to CCR5-dependent HIV-1 strains (R5). We observed a strong correlation between T cell activation, expression of KLF2 and CCR5, and susceptibility to infection. To directly measure how KLF2 affects CCR5 regulation, we introduced small interfering RNA targeting KLF2 expression and demonstrated that reduced KLF2 expression also resulted in less CCR5. Chromatin immunoprecipitation assays identified KLF2 bound to the CCR5 promoter in resting but not CD3/28 activated T cells, suggesting that KLF2 directly regulates CCR5 expression. Introduction of KLF2 under control of a heterologous promoter could restore CCR5 expression and R5 susceptibility to CD3/28 costimulated T cells and some transformed cell lines. Thus, KLF2 is a host factor that modulates CCR5 expression in CD4 T cells and influences susceptibility to R5 infection.
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Predisposición Genética a la Enfermedad , Infecciones por VIH/inmunología , VIH-1/inmunología , Factores de Transcripción de Tipo Kruppel/fisiología , Receptores CCR5/biosíntesis , Antagonistas de los Receptores CCR5 , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD4-Positivos/metabolismo , Linfocitos T CD4-Positivos/virología , Línea Celular Transformada , Regulación hacia Abajo/genética , Regulación hacia Abajo/inmunología , Sistemas de Liberación de Medicamentos/métodos , Predisposición Genética a la Enfermedad/etiología , Infecciones por VIH/genética , Infecciones por VIH/metabolismo , Humanos , Factores de Transcripción de Tipo Kruppel/metabolismo , Activación de Linfocitos/genética , Activación de Linfocitos/inmunología , Cultivo Primario de Células , Unión Proteica/genética , Unión Proteica/inmunología , ARN Interferente Pequeño/farmacología , Receptores CCR5/genética , Fase de Descanso del Ciclo Celular/genética , Fase de Descanso del Ciclo Celular/inmunologíaRESUMEN
The first use of lentiviral vectors in humans involved transduction of mature T-cells with an human immunodeficiency virus (HIV)-derived env antisense (envAS) vector to protect cells from HIV infection. In that study, only a minority of the patient T-cell population could be gene-modified, raising the question of whether the altered cells could affect replicating HIV populations. We investigated this using humanized NOD/SCID IL-2Rgamma(null) (hNSG) mice reconstituted with approximately 4-11% envAS-modified human T-cells. Mice were challenged with HIV-1(NL4-3), which has an env perfectly complementary to envAS, or with HIV-1(BaL), which has a divergent env. No differences were seen in viral titer between mice that received envAS-modified cells and control mice that did not. Using 454/Roche pyrosequencing, we analyzed the mutational spectrum in HIV populations in serum-from 33 mice we recovered 84,074 total reads comprising 31,290 unique sequence variants. We found enrichment of A-to-G transitions and deletions in envAS-treated mice, paralleling a previous tissue culture study where most target cells contained envAS, even though minority of cells were envAS-modified here. Unexpectedly, this enrichment was only detected after the challenge with HIV-1(BaL), where the viral genome would form an imperfect duplex with envAS, and not HIV-1(NL4-3), where a perfectly matched duplex would form.
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Infecciones por VIH/terapia , VIH-1/genética , Inmunoterapia Adoptiva , ARN sin Sentido/genética , Linfocitos T/trasplante , Productos del Gen env del Virus de la Inmunodeficiencia Humana/genética , Animales , Secuencia de Bases , Variación Genética , Infecciones por VIH/virología , Humanos , Ratones , Ratones Endogámicos NOD , Ratones SCID , ARN Viral/genética , Linfocitos T/inmunología , Transducción Genética , Replicación Viral/genéticaRESUMEN
Rhesus TRIM5alpha (rhTRIM5alpha), but not human TRIM5alpha (huTRIM5alpha), potently inhibits human immunodeficiency virus (HIV) infection and is thus a potentially valuable therapeutic tool. Primary human CD4 T cells engineered to express rhTRIM5alpha were highly resistant to cell-free HIV type 1 (HIV-1) infection. However, when cocultured with unmodified T cells, rhTRIM5alpha-expressing cells became highly permissive to HIV-1 infection. Physical separation of rhTRIM5alpha-expressing cells and unmodified cells revealed that rhTRIM5alpha efficiently restricts cell-free but not cell-associated HIV transmission. Furthermore, we observed that HIV-infected human cells could infect rhesus CD4 T cells by cell-to-cell contact, but the infection was self-limiting. Subsequently, we noted that a spreading infection ensued when HIV-1-infected rhTRIM5alpha-expressing human cells were cultured with huTRIM5alpha- but not rhTRIM5alpha-expressing cells. Our results suggest that cell-associated HIV transmission in humans is blocked only when both donor and recipient cells express rhTRIM5alpha. These studies further define the role of rhTRIM5alpha in cell-free and cell-associated HIV transmission and delineate the utility of rhTRIM5alpha in anti-HIV therapy.
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VIH-1/inmunología , Inmunidad Innata , Proteínas/inmunología , Animales , Linfocitos T CD4-Positivos/virología , Células Cultivadas , Técnicas de Cocultivo , VIH-1/crecimiento & desarrollo , Humanos , Macaca mulatta , Ubiquitina-Proteína LigasasRESUMEN
This study analyzed the antigen-specific (Gag, Nef, Rev, and Tat) IgM, IgG, and IgA humoral responses during the first 200 days of SIVmac251 infection in cynomolgus macaques. These responses were tested for correlation with the CD4(+) T-cell-related hematologic parameters and viral load throughout the course of the study (acute and chronic infection, during and after antiretroviral therapy). Strong inverse correlations were observed between the percentage of CD4(+) T cells at almost every timepoint of the study and the levels of IgM (but not IgG and IgA) against Gag, Nef, and Rev (but not Tat) measured after, but not during, the primary peak of IgM response. Significant levels of persistent antigen-specific IgMs may reflect the prevalence of mature plasma cells that have not undergone immunoglobulin class switching, possibly due to defects in helper T-cell function. Strong correlations were observed between the preinfection CD4(+) T-cell count or CD4/CD8 ratio and the same parameters measured throughout the study, suggesting the importance of preinfection immune status as a determinant of disease progression. The negative correlations between the post-acute-phase IgM levels and the percentage of CD4(+) T cells at later times during the study suggest the potential prognostic value of this measurement.
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Anticuerpos Antivirales/sangre , Productos del Gen gag/inmunología , Productos del Gen rev/inmunología , Inmunoglobulinas/sangre , Síndrome de Inmunodeficiencia Adquirida del Simio/inmunología , Virus de la Inmunodeficiencia de los Simios , Linfocitos T Colaboradores-Inductores/inmunología , Proteínas Reguladoras y Accesorias Virales/inmunología , Animales , Antirretrovirales/uso terapéutico , Especificidad de Anticuerpos , Biomarcadores/sangre , Linfocitos T CD8-positivos/inmunología , Modelos Animales de Enfermedad , Progresión de la Enfermedad , Recuento de Linfocitos , Macaca fascicularis , Síndrome de Inmunodeficiencia Adquirida del Simio/diagnóstico , Síndrome de Inmunodeficiencia Adquirida del Simio/tratamiento farmacológico , Síndrome de Inmunodeficiencia Adquirida del Simio/virología , Virus de la Inmunodeficiencia de los Simios/inmunología , Factores de Tiempo , Carga ViralRESUMEN
Hairpin ribozymes derived from the negative strand of satellite RNAs from the tobacco ringspot virus (sTRSV) can be engineered to target and cleave a variety of heterologous RNAs from both cellular and viral transcripts. Attention to design and targeting rules and optimization of helix 1 length and catalytic efficiency in vitro may increase the efficacy of hairpin ribozymes in reducing the expression of targeted transcripts. Here, principles for the design and targeting of sTRSV-derived hairpin ribozymes are described, as well as methods and materials for optimizing helix 1 length, and for conducting an initial screen of catalytic efficiency to identify promising candidates for further evaluation. Examples are provided for hairpin ribozymes that target human and mouse transforming growth-factor beta (TGF-beta), as well as human polycystic kidney disease gene 1 (PKD1) and JC virus large T-antigen. The tetraloop modification of the sTRSV hairpin ribozyme is considered superior to designs based on the native sTRSV hairpin ribozyme, given its potential to yield considerable improvements in stability and catalytic efficiency.
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Nepovirus/genética , ARN Catalítico/metabolismo , ARN Viral/metabolismo , Secuencia de Bases , Catálisis , Ingeniería Genética/métodos , Marcadores Genéticos , Humanos , Datos de Secuencia Molecular , Conformación de Ácido Nucleico , ARN Catalítico/química , ARN Catalítico/genética , ARN Viral/química , ARN Viral/genética , Especificidad por Sustrato , Moldes Genéticos , Transcripción Genética , Factor de Crecimiento Transformador beta/genéticaRESUMEN
T-cell receptor excision circles (TREC) may be a useful surrogate marker in HIV-1 infection for evaluating the likelihood of continued clinical stability and/or the response to therapeutics, including vaccines. Analysis of TREC in SHIV and SIV models of HIV-1 infection may provide additional information concerning the utility of TREC as a marker. We measured TREC in peripheral blood mononuclear cells (PBMC) from rhesus macaques in SHIV89.6p (n = 20) and SIVmac251 (n = 11) models of HIV-1 infection. TREC were also evaluated in tissues in the SIVmac251 model at end-point. In the SHIV89.6p model, TREC in PBMC were significantly lower at 12 weeks postinfection compared to preinfection levels. The decrease in TREC correlated with the decline in CD4+ T cells (r(s) = 0.496; P = 0.026), which in turn correlated inversely with serum viral loads at end-point (r(s) = -0.517; P = 0.019). Macaques that controlled SHIV89.6p infection to some degree (n = 6) had higher TREC at study end-point (P = 0.017). In the SIVmac251 model, TREC in PBMC were significantly reduced after 17 months of infection (P = 0.012) despite receiving highly active antiretroviral therapy (HAART) consisting of didanosine (ddI) and (R)-9-(2-phosphonylmethoxypropyl)-adenine (PMPA) when not cycling off therapy during scheduled treatment interruptions (STI). However, macaques that received continuous hydroxyurea (HU) in addition to the HAART regimen had higher end-point TREC compared to the non-HU group (P = 0.041), and the reduction in TREC observed at end-point within the HU group was not significant. In the SIVmac251 model, TREC correlated with the percentage of CD4+ T cells (r(s) = 0.426; P = 0.048) and CD4+CD28+ T cells (r(s) = 0.624; P = 0.002), and inversely with CD8+ T cells (r(s) = -0.622; P = 0.002), CD8+CD28- T cells (r(s) = -0.516; P = 0.014), and serum viral loads (r(s) = -0.627; P = 0.039). High levels of TREC were observed in the thymus, levels comparable to PBMC were seen in the lymph node, and low but detectable levels of TREC were present in bone marrow. The use of correlates of TREC as covariates in ANCOVA revealed that the decline in TREC in the SHIV 89.6p model reflected the decline in the percentage of CD4+ T-cells due to viral cytopathogenicity. In the SIVmac251 model, the decline in TREC was related to increased immune activation and proliferation due to viral replication, as reflected by decreases in percentages of CD4+CD28+ T cells and increases in CD8+ and CD8+CD28- T cells.
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Síndrome de Inmunodeficiencia Adquirida/inmunología , Receptores de Antígenos de Linfocitos T/genética , Síndrome de Inmunodeficiencia Adquirida del Simio/tratamiento farmacológico , Síndrome de Inmunodeficiencia Adquirida del Simio/inmunología , Virus de la Inmunodeficiencia de los Simios/inmunología , Linfocitos T/inmunología , Análisis de Varianza , Animales , Fármacos Anti-VIH/uso terapéutico , Terapia Antirretroviral Altamente Activa , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/inmunología , Modelos Animales de Enfermedad , Macaca mulatta , Linfocitos T/clasificación , Factores de TiempoRESUMEN
The HIV-1 regulatory protein Tat and the accessory protein Vpr are thought to stimulate viral replication and contribute to viral pathogenesis as extracellular proteins. Humoral immune responses to these early viral proteins may therefore be beneficial. We examined serum anti-Tat and anti-Vpr IgG by ELISA in the GRIV cohort of HIV-1 seropositive slow/non-progressors (NP) and fast-progressors (FP), and in seronegative controls. Based on information obtained during a brief follow-up period (median = 20 months), NPs were sub-grouped as those maintaining non-progression status and therefore stable (NP-S), and those showing signs of disease progression (NP-P). As the primary comparison, initial serum anti-Tat and anti-Vpr IgG (prior to follow-up) were analyzed in the NP sub-groups and in FPs. Anti-Tat IgG was significantly higher in stable NP-S compared to unstable NP-P (P = 0.047) and FPs (P < 0.0005); the predictive value of higher anti-Tat IgG for maintenance of non-progression status was 92% (P = 0.029). In contrast, no-difference was observed in anti-Vpr IgG between NP-S and NP-P, although both were significantly higher than FPs (P = 0.001). Serum anti-Tat IgG mapped to linear epitopes within the amino-terminus, the basic domain and the carboxy-terminal region of Tat in stable NP-S. Similar epitopes were identified in patients immunized with the Tat-toxoid in a Phase I study in Milan. High titer serum anti-Tat IgG from both GRIV and Milan cohorts cross-reacted in ELISA with Tat from diverse viral isolates, including HIV-1 subtype-E (CMU08) and SIVmac251 Tat; a correlation was observed between anti-Tat IgG titers and cross-reactivity. These results demonstrate that higher levels of serum anti-Tat IgG, but not anti-Vpr IgG, are associated with maintenance of non-progression status in HIV-1 infection. Evidence that vaccination with the Tat toxoid induces humoral immune responses to Tat similar to those observed in stable non-progressors is encouraging for vaccine strategies targeting Tat.
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Productos del Gen tat/inmunología , Productos del Gen vpr/inmunología , Anticuerpos Anti-VIH/sangre , VIH-1/inmunología , Estudios de Cohortes , Reacciones Cruzadas/inmunología , Ensayo de Inmunoadsorción Enzimática/métodos , Estudios de Seguimiento , Sobrevivientes de VIH a Largo Plazo , Seropositividad para VIH/inmunología , Humanos , Inmunoglobulina G/sangre , Inmunoglobulina G/inmunología , Mapeo Peptídico/métodos , Productos del Gen tat del Virus de la Inmunodeficiencia Humana , Productos del Gen vpr del Virus de la Inmunodeficiencia HumanaRESUMEN
This study compared immune responses in rhesus macaques immunized with unmodified HIV-1 IIIB Tat, SHIV89.6P Tat, and carboxymethylated IIIB and 89.6P Tat toxoids. Immunization with either IIIB or 89.6P preparation induced high titer and broadly crossreactive serum anti-Tat IgG that recognized HIV-1 subtype-E and SIVmac251 Tat. However, the response was delayed, and titers were lower in 89.6P vaccination groups. Serum anti-Tat IgG recognized peptides corresponding to the amino-terminus, basic domain, and carboxy-terminal region. Cellular proliferative responses to Tat toxoids corresponding to the immunogen were evident in vitro in both IIIB and 89.6P groups. Crossreactive proliferative responses were observed in IIIB groups in response to stimulation with 89.6P or SIVmac251 Tat toxoids, but were much less prevalent in 89.6P groups. The truncated 86 amino acid IIIB Tat appears to be more immunogenic than the 102 amino acid 89.6P Tat with respect to both humoral and cellular immune responses, and may be a better vaccine component. Despite induction of robust humoral and cellular immune responses (including both CD4+ and CD8+ T-cell responses) to Tat, all animals were infected upon intravenous challenge with 30 MID(50) of SHIV89.6P and outcome of vaccine groups was not different from controls. Sequencing both Tat exons from serum viral RNA revealed no evidence of escape mutants. These results suggest that with intravenous SHIV89.6P challenge in rhesus macaques, precipitous CD4+ T-cell decline overwhelms potentially protective immune responses. Alternatively, Tat specific CD8+ T-cell responses may not appropriately recognize infected cells in vivo in this model. In view of evidence demonstrating Tat specific CTLs in the SIV model and in humans infected with HIV-1, results in this pathogenic SHIV model may not apparently predict the efficacy of this approach in human studies. The potency and cross-reactivity of these immune responses confirm Tat toxoid as an excellent candidate vaccine component.
Asunto(s)
Vacunas contra el SIDA/inmunología , Productos del Gen tat/inmunología , VIH-1/inmunología , Toxoides/inmunología , Vacunas contra el SIDA/administración & dosificación , Secuencia de Aminoácidos , Animales , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/inmunología , Ensayo de Inmunoadsorción Enzimática , Productos del Gen tat/administración & dosificación , Interferón gamma/metabolismo , Leucocitos Mononucleares/inmunología , Macaca mulatta , Datos de Secuencia Molecular , Toxoides/administración & dosificación , Productos del Gen tat del Virus de la Inmunodeficiencia HumanaRESUMEN
The regulatory proteins Nef, Rev, and Tat of human immunodeficiency virus type 1 (HIV-1) are attractive targets for vaccine development, since induction of effective immune responses targeting these early proteins may best control virus replication. Here we investigated whether vaccination with biologically active Tat or inactive Tat toxoid derived from HIV-1(IIIB) and simian-human immunodeficiency virus (SHIV) strain 89.6p would induce protective immunity in rhesus macaques. Vaccination induced high titers of anti-Tat immunoglobulin G in all immunized animals by week 7, but titers were somewhat lower in the 89.6p Tat group. Dominant B-cell epitopes mapped to the amino terminus, the basic domain, and the carboxy-terminal region. Tat-specific T-helper responses were detected in 50% of immunized animals. T-cell epitopes appeared to map within amino acids (aa) 1 to 24 and aa 37 to 66. In addition, Tat-specific gamma interferon responses were detected in CD4+ and/or CD8+ T lymphocytes in 11 of 16 immunized animals on the day of challenge. However, all animals became infected upon intravenous challenge with 30 50% minimal infective doses of SHIV 89.6p, and there were no significant differences in viral loads or CD4+ T-cell counts between immunized and control animals. Thus, vaccination with HIV-1(IIIB) or SHIV 89.6p Tat or with Tat toxoid preparations failed to confer protection against SHIV 89.6p infection despite robust Tat-specific humoral and cellular immune responses in some animals. Given its apparent immunogenicity, Tat may be more effective as a component of a cocktail vaccine in combination with other regulatory and/or structural proteins of HIV-1.