Tat is a key HIV regulatory protein produced very early after infection, prior to virus integration, and necessary for viral gene expression, cell-to-cell virus transmission and disease progression. Previous studies in natural HIV infection, indicated that the presence of a Tat-specific immune response correlates with a lower incidence and reduced risk of progression to AIDS as compared to anti-Tat negative individuals suggesting that an immune response to Tat may exert a protective role and control the progression to AIDS in vivo. On the basis of the above mentioned consideration, the present study was directed at investigating the seroprevalence of anti-Tat antibodies in HIV-infected South African patients.
This is an observational, cross-sectional study aimed at assessing the frequency, magnitude and quality of the anti-Tat antibody response in both antiretroviral (ARV)-treated and treatment-naïve HIV-infected South African adults, and at exploring the correlation between the presence of anti-Tat antibody response and the immunological status of participants as well as with the presence of co-infections such as HBV, syphilis and HPV (the latter only for female participants). The study has involved 531 participants and provided important information for the planning, design and conduction of future therapeutic clinical trials with the Tat-based HIV vaccine in South African individuals. This study is conducted in the frame of the Government-to-Government cooperation program N. AID 8421, funded by the Italian Ministry of Foreign Affairs-Directorate General for Development Cooperation (MAE-DGCS) and jointly implemented by the Italian Istituto Superiore di Sanita' (ISS) and the South African Department of Health in collaboration with the South African AIDS Vaccine Initiative of the Medical Research Council (MRC-SAAVI)
Study Type
OBSERVATIONAL
Enrollment
531
Walter Sisulu University HIV Vaccine Research Unit
Mthatha, Eastern Cape, South Africa
Mecru Clinical Research Unit (MeCRU)
Medunsa, Gauteng, South Africa
Anti-Tat Antibody Responses
Assessment of serum anti-Tat antibodies. Anti-Tat humoral immune response will include the determination of serum IgM, IgG and IgA antibodies against both clade B- and C-derived Tat proteins and titration of IgM, IgG and IgA anti-Tat antibodies.
Time frame: Up to 14 months
Virological status of anti-Tat positive and negative participants
HIV viral load and clinical status on anti-Tat+ versus anti-Tat- participants. The effect of ARV treatment non-compliance on viral load in anti-Tat+ versus anti-Tat- participants has been evaluated within the ARV-treated study group on the basis of the relevant available information. Hepatitis B, Syphilis, HPV co-infections Assessment.
Time frame: Up to 14 months
Immunological status of anti-Tat positive and negative participants
Assessment of CD4 T cell counts. Exploratory immunological assays may be performed on available residual samples for a more in-depth characterisation of the immune response.
Time frame: Up to 14 months
Immune activation status of anti-Tat positive and negative participants
Assessment of Immune-activation markers on CD4+ and CD8+ T cells (CD25+, CD38+ and HLA-DR+).
Time frame: Up to 14 months
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