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Nicoli F, Chachage M, Clowes P, Bauer A, Kowour D, Ensoli B, Cafaro A, Maboko L, Hoelscher M, Gavioli R, Saathoff E, Geldmacher C. Association between different anti-Tat antibody isotypes and HIV disease progression: data from an African cohort. BMC Infect Dis 2016; 16:344. [PMID: 27450538 PMCID: PMC4957276 DOI: 10.1186/s12879-016-1647-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 06/07/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The presence of IgG and IgM against Tat, an HIV protein important for viral replication and immune dysfunction, is associated with slow disease progression in clade B HIV-infected individuals. However, although Tat activities strictly depend on the viral clade, our knowledge about the importance of anti-Tat antibodies in non-clade B HIV infection is poor. The objective of this study was to investigate the association of different anti-Tat antibody isotypes with disease progression in non-clade B HIV-infected subjects and to study the relationship between anti-Tat humoral responses and immunological abnormalities. METHODS Anti-clade B and -clade C Tat IgG, IgM and IgA titers were assessed in serum samples from 96 cART-naïve subjects with chronic HIV infection from Mbeya, Tanzania, and associated with CD4(+) T cell count, plasma viremia and CD4(+) and CD8(+) T cell phenotypes. RESULTS Anti-Tat IgM were preferentially detected in chronic HIV-infected subjects with low T cell activation (p-value = 0.03) and correlated with higher CD4(+) T cell counts and lower viral loads irrespective of the duration of infection (p-value = 0.019 and p-value = 0.037 respectively). Conversely, anti-Tat IgA were preferentially detected in individuals with low CD4(+) T cell counts and high viral load (p-value = 0.02 and p-value < 0.001 respectively). The simultaneous presence of anti-Tat IgG and IgM protected from fast CD4(+) T cell decline (p-value < 0.01) and accumulation of CD38(+)HLADR(+)CD8(+) T cells (p- value = 0.029). CONCLUSIONS Anti-Tat IgG alone are not protective in non-clade B infected subjects, unless concomitant with IgM, suggesting a protective role of persistent anti-Tat IgM irrespective of the infecting clade.
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Affiliation(s)
- Francesco Nicoli
- Center for International Health, Ludwig-Maximilians-Universität München, Leopoldstraße 7, 80802, Munich, Germany. .,Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy. .,Current address: CIMI INSERM U1135, 91 bd del'Hopital, 75013, Paris, France.
| | - Mkunde Chachage
- Center for International Health, Ludwig-Maximilians-Universität München, Leopoldstraße 7, 80802, Munich, Germany.,National Institute for Medical Research (NIMR)-Mbeya Medical Research Centre, Mbeya, Tanzania
| | - Petra Clowes
- National Institute for Medical Research (NIMR)-Mbeya Medical Research Centre, Mbeya, Tanzania.,Division of Infectious Diseases and Tropical Medicine, Medical Center of the University of Munich (LMU), Munich, Germany
| | - Asli Bauer
- National Institute for Medical Research (NIMR)-Mbeya Medical Research Centre, Mbeya, Tanzania.,Division of Infectious Diseases and Tropical Medicine, Medical Center of the University of Munich (LMU), Munich, Germany
| | - Dickens Kowour
- National Institute for Medical Research (NIMR)-Mbeya Medical Research Centre, Mbeya, Tanzania
| | - Barbara Ensoli
- National AIDS Center, Istituto Superiore di Sanità, Rome, Italy
| | - Aurelio Cafaro
- National AIDS Center, Istituto Superiore di Sanità, Rome, Italy
| | - Leonard Maboko
- National Institute for Medical Research (NIMR)-Mbeya Medical Research Centre, Mbeya, Tanzania
| | - Michael Hoelscher
- Division of Infectious Diseases and Tropical Medicine, Medical Center of the University of Munich (LMU), Munich, Germany.,German Center for Infection Research (DZIF), partner site Munich, Munich, Germany
| | - Riccardo Gavioli
- Department of Life Sciences and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Elmar Saathoff
- Division of Infectious Diseases and Tropical Medicine, Medical Center of the University of Munich (LMU), Munich, Germany.,German Center for Infection Research (DZIF), partner site Munich, Munich, Germany
| | - Christof Geldmacher
- Division of Infectious Diseases and Tropical Medicine, Medical Center of the University of Munich (LMU), Munich, Germany.,German Center for Infection Research (DZIF), partner site Munich, Munich, Germany
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Mediouni S, Darque A, Ravaux I, Baillat G, Devaux C, Loret EP. Identification of a highly conserved surface on Tat variants. J Biol Chem 2013; 288:19072-80. [PMID: 23678001 DOI: 10.1074/jbc.m113.466011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Extracellular Tat is suspected to protect HIV-1-infected cells from cellular immunity. Seropositive patients are unable to produce neutralizing antibodies against Tat, and Tat is still secreted under antiviral treatment. In mice, the Tat OYI vaccine candidate generates neutralizing antibodies such as the mAb 7G12. A peptide called MIMOOX was designed from fragments of Tat OYI identified as the possible binding site for mAb 7G12. MIMOOX was chemically synthesized, and its structure was stabilized with a disulfide bridge. Circular dichroism spectra showed that MIMOOX had mainly β turns but no α helix as Tat OYI. MIMOOX was recognized by mAb 7G12 in ELISA only in reduced conditions. Moreover, a competitive recognition assay with mAb 7G12 between MIMOOX and Tat variants showed that MIMOOX mimics a highly conserved surface in Tat variants. Rat immunizations with MIMOOX induce antibodies recognizing Tat variants from the main HIV-1 subtypes and confirm the Tat OYI vaccine approach.
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Affiliation(s)
- Sonia Mediouni
- Aix Marseille Université, Unité Mixte de Recherche (UMR) 5236 CNRS, Equipe Technologique de Recherches Appliquées sur le VIH-1 (ETRAV), Faculté de Pharmacie, 27 BD Jean Moulin, 13385 Marseille Cedex 5, France
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Chen Q, Li L, Liao W, Zhang H, Wang J, Sheng B, Zhang H, Huang X, Ding Y, Zhang T, Cao J, Wu H, Pan W. Characterization of Tat antibody responses in Chinese individuals infected with HIV-1. PLoS One 2013; 8:e60825. [PMID: 23565278 PMCID: PMC3614898 DOI: 10.1371/journal.pone.0060825] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Accepted: 03/02/2013] [Indexed: 11/18/2022] Open
Abstract
HIV-1 Tat is an important regulatory protein involved in AIDS pathogenesis. However, the immunoprofiles of anti-Tat responses remain unclear. We analysed the immunoprofiles of the anti-Tat antibody responses and the neutralizing activities. Out of 326 HIV-1-seropositive individuals, 12.9% were positive for anti-Tat antibodies. We found six different immunological profiles of anti-Tat antibody responses: full-potential response, combined response, N-specific response, C-specific response, full-length Tat-specific response and Tat-related response. These responses represent two types of anti-Tat responses: the major complete response and the alternative C-prone response. A Tat-neutralizing activity is significantly higher in anti-Tat-seropositive samples than anti-Tat-negative or healthy blood-donor samples, and significantly correlates with the anti-Tat reactivities. The data here could contribute to a better understanding of the significance of anti-Tat responses in preventing HIV pathogenesis and could be useful for designing more effective vaccines in the future.
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Affiliation(s)
- Qiuli Chen
- Department of Microbiology, Second Military Medical University, Shanghai, China
| | - Lan Li
- Center for Infectious Diseases, Beijing You’an Hospital, Beijing, China
| | - Wenting Liao
- Department of Microbiology, Second Military Medical University, Shanghai, China
- College of High Altitude Military Medicine, Third Military Medical University, Chongqing, China
| | - Hongwei Zhang
- Center for Infectious Diseases, Beijing You’an Hospital, Beijing, China
| | - Jinhong Wang
- Department of Microbiology, Second Military Medical University, Shanghai, China
| | - Bo Sheng
- Center for Infectious Diseases, Beijing You’an Hospital, Beijing, China
| | - Huaqun Zhang
- Department of Microbiology, Second Military Medical University, Shanghai, China
| | - Xiaojie Huang
- Center for Infectious Diseases, Beijing You’an Hospital, Beijing, China
| | - Yingying Ding
- Department of Microbiology, Second Military Medical University, Shanghai, China
| | - Tong Zhang
- Center for Infectious Diseases, Beijing You’an Hospital, Beijing, China
| | - Jie Cao
- Department of Microbiology, Second Military Medical University, Shanghai, China
| | - Hao Wu
- Center for Infectious Diseases, Beijing You’an Hospital, Beijing, China
- * E-mail: (WP); (HW)
| | - Wei Pan
- Department of Microbiology, Second Military Medical University, Shanghai, China
- * E-mail: (WP); (HW)
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Abstract
Since HIV-1 was identified, development of a preventive vaccine has been a major goal. Significant progress toward that goal has been made by 2010. In macaques, a vigorous T effector cell response has protected some animals from disease caused by simian immunodeficiency virus (SIV). Broadly, neutralizing human anti-HIV antibodies have been isolated and their structures, and targets are rapidly being elucidated. For the first time an AIDS vaccine has shown modest protective efficacy in a human clinical trial. To reach the final goal, there is a need for a coordinated global effort, including a range of approaches including novel high-throughput screening techniques, X-ray crystallography, and monoclonal antibody isolation, analysis of T cell responses and their impact on disease progression, human epidemiology, as well as targeted studies in nonhuman primates. African research teams as well as cohorts of healthy volunteers and HIV-infected individuals have contributed to HIV vaccine research and development in many important ways. It is essential that this work continue to speed the development and deployment of a vaccine suitable for African populations.
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Banerjee K, Klasse P, Sanders RW, Pereyra F, Michael E, Lu M, Walker BD, Moore JP. IgG subclass profiles in infected HIV type 1 controllers and chronic progressors and in uninfected recipients of Env vaccines. AIDS Res Hum Retroviruses 2010; 26:445-58. [PMID: 20377426 DOI: 10.1089/aid.2009.0223] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
We have studied IgG subclass responses to the HIV-1 proteins gp120, gp41, p24, and Tat in individuals who control their infection without using antiretroviral drugs (HIV-1 controllers; HC) or who progress to disease (chronic progressors; CP). We also measured IgG subclass titers to gp120 in vaccinated individuals. In all cases, the IgG1 subclass dominated the overall response to each antigen. The only IgG titer that differed significantly between the HC and CP groups was to the p24 Gag protein, which was higher in the HC group. IgG1 titers to both p24 and gp120 were significantly higher in the HC group, and IgG3 anti-gp120 antibodies, although rare, were detected more frequently in that group than in CP. Overall, significantly more patients had IgG2 antibodies to gp120 than to gp41. Antibodies to other IgG subclasses were infrequent and their frequency or titers did not differ between the two patient groups. Anti-gp41 and anti-Tat responses also did not correlate with immune control, and anti-Tat antibodies were infrequently detected. Although we found isotypic differences in IgG responses to HIV-1 antigens among vaccinees and the HC and CP individuals, there were no indications of differential T(H)1:T(H)2 polarization between the different groups.
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Affiliation(s)
- Kaustuv Banerjee
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York
| | - P.J. Klasse
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York
| | - Rogier W. Sanders
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York
- Department of Medical Microbiology, Academic Medical Center, 1105 AZ Amsterdam, The Netherlands
| | - Florencia Pereyra
- Ragon Institute of MGH, MIT, and Harvard, Massachussetts General Hospital and Division of AIDS, Harvard Medical School, Boston, Massachusetts
| | - Elizabeth Michael
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York
| | - Min Lu
- Department of Biochemistry, Weill Cornell Medical College, New York, New York
| | - Bruce D. Walker
- Ragon Institute of MGH, MIT, and Harvard, Massachussetts General Hospital and Division of AIDS, Harvard Medical School, Boston, Massachusetts
- Howard Hughes Medical Institute, Massachusetts General Hospital and Division of AIDS, Harvard Medical School, Boston, Massachusetts
| | - John P. Moore
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York
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Kashi VP, Jacob RA, Paul S, Nayak K, Satish B, Swaminathan S, Satish KS, Ranga U. HIV-1 Tat-specific IgG antibodies in high-responders target a B-cell epitope in the cysteine-rich domain and block extracellular Tat efficiently. Vaccine 2009; 27:6739-47. [PMID: 19744585 DOI: 10.1016/j.vaccine.2009.08.078] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2009] [Revised: 08/19/2009] [Accepted: 08/22/2009] [Indexed: 10/20/2022]
Abstract
Tat, an important regulatory protein of HIV-1, has been implicated in HIV-related pathogenesis. Immune responses to Tat, although underrepresented, confer protection against disease progression, in natural infection and experimental immunization, making Tat an attractive vaccine candidate. Information on immune responses to Tat from India which has the second largest HIV incidence has been lacking. Here we report a cross-sectional study evaluating the humoral response to Tat from a large number of samples from two southern states of India. 14% of the seropositive (63/447) and 4.6% of seronegative samples (7/150) harbored Tat-reactive antibodies. A significant number of the seropositive samples contained high levels of anti-Tat antibodies (31/447) which demonstrated class-switch to IgG1 and bound to Tat with high avidity. Cross-reactivity analysis showed that these antibodies interacted with Tat from different clades with variable degree with the highest interaction with subtype-AE and the least with subtype-B Tat. Importantly, a B-cell epitope in the cysteine-rich domain was found to be the most immunodominant one and antibodies interacting with this epitope blocked extracellular Tat efficiently. To the best of our knowledge this is the first report on immune responses to Tat from Indian populations and the data presented here could significantly contribute to HIV Tat vaccine design.
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Campbell GR, Loret EP. What does the structure-function relationship of the HIV-1 Tat protein teach us about developing an AIDS vaccine? Retrovirology 2009; 6:50. [PMID: 19467159 PMCID: PMC2693501 DOI: 10.1186/1742-4690-6-50] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2009] [Accepted: 05/25/2009] [Indexed: 11/03/2022] Open
Abstract
The human immunodeficiency virus type 1 (HIV-1) trans-activator of transcription protein Tat is an important factor in viral pathogenesis. In addition to its function as the key trans-activator of viral transcription, Tat is also secreted by the infected cell and taken up by neighboring cells where it has an effect both on infected and uninfected cells. In this review we will focus on the relationship between the structure of the Tat protein and its function as a secreted factor. To this end we will summarize some of the exogenous functions of Tat that have been implicated in HIV-1 pathogenesis and the impact of structural variations and viral subtype variants of Tat on those functions. Finally, since in some patients the presence of Tat-specific antibodies or CTL frequencies are associated with slow or non-progression to AIDS, we will also discuss the role of Tat as a potential vaccine candidate, the advances made in this field, and the importance of using a Tat protein capable of eliciting a protective or therapeutic immune response to viral challenge.
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Affiliation(s)
- Grant R Campbell
- Department of Pediatrics, Division of Infectious Diseases, University of California San Diego, La Jolla, California 92093-0672, USA.
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Florese RH, Demberg T, Xiao P, Kuller L, Larsen K, Summers LE, Venzon D, Cafaro A, Ensoli B, Robert-Guroff M. Contribution of nonneutralizing vaccine-elicited antibody activities to improved protective efficacy in rhesus macaques immunized with Tat/Env compared with multigenic vaccines. THE JOURNAL OF IMMUNOLOGY 2009; 182:3718-27. [PMID: 19265150 DOI: 10.4049/jimmunol.0803115] [Citation(s) in RCA: 116] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Previously, chronic-phase protection against SHIV(89.6P) challenge was significantly greater in macaques primed with replicating adenovirus type 5 host range mutant (Ad5hr) recombinants encoding HIVtat and env and boosted with Tat and Env protein compared with macaques primed with multigenic adenovirus recombinants (HIVtat, HIVenv, SIVgag, SIVnef) and boosted with Tat, Env, and Nef proteins. The greater protection was correlated with Tat- and Env-binding Abs. Because the macaques lacked SHIV(89.6P)-neutralizing activity prechallenge, we investigated whether Ab-dependent cellular cytotoxicity (ADCC) and Ab-dependent cell-mediated viral inhibition (ADCVI) might exert a protective effect. We clearly show that Tat can serve as an ADCC target, although the Tat-specific activity elicited did not correlate with better protection. However, Env-specific ADCC activity was consistently higher in the Tat/Env group, with sustained cell killing postchallenge exhibited at higher levels (p < 0.00001) for a longer duration (p = 0.0002) compared with the multigenic group. ADCVI was similarly higher in the Tat/Env group and significantly correlated with reduced acute-phase viremia at wk 2 and 4 postchallenge (p = 0.046 and 0.011, respectively). Viral-specific IgG and IgA Abs in mucosal secretions were elicited but did not influence the outcome of the i.v. SHIV(89.6P) challenge. The higher ADCC and ADCVI activities seen in the Tat/Env group provide a plausible mechanism responsible for the greater chronic-phase protection. Because Tat is known to enhance cell-mediated immunity to coadministered Ags, further studies should explore its impact on Ab induction so that it may be optimally incorporated into HIV vaccine regimens.
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Watkins JD, Campbell GR, Halimi H, Loret EP. Homonuclear 1H NMR and circular dichroism study of the HIV-1 Tat Eli variant. Retrovirology 2008; 5:83. [PMID: 18808674 PMCID: PMC2557015 DOI: 10.1186/1742-4690-5-83] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2008] [Accepted: 09/22/2008] [Indexed: 11/30/2022] Open
Abstract
Background The HIV-1 Tat protein is a promising target to develop AIDS therapies, particularly vaccines, due to its extracellular role that protects HIV-1-infected cells from the immune system. Tat exists in two different lengths, 86 or 87 residues and 99 or 101 residues, with the long form being predominant in clinical isolates. We report here a structural study of the 99 residue Tat Eli variant using 2D liquid-state NMR, molecular modeling and circular dichroism. Results Tat Eli was obtained from solid-phase peptide synthesis and the purified protein was proven biologically active in a trans-activation assay. Circular dichroism spectra at different temperatures up to 70°C showed that Tat Eli is not a random coil at 20°C. Homonuclear 1H NMR spectra allowed us to identify 1639 NMR distance constraints out of which 264 were interresidual. Molecular modeling satisfying at least 1474 NMR constraints revealed the same folding for different model structures. The Tat Eli model has a core region composed of a part of the N-terminus including the highly conserved Trp 11. The extra residues in the Tat Eli C-terminus protrude from a groove between the basic region and the cysteine-rich region and are well exposed to the solvent. Conclusion We show that active Tat variants share a similar folding pattern whatever their size, but mutations induce local structural changes.
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Affiliation(s)
- Jennifer D Watkins
- Faculté de Pharmacie, Unité Mixte de Recherche Université de la Méditerranée/INSERM U911, Université de la Méditerranée, Marseille, France.
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