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Vulnerable targets in HIV-1 Pol for attenuation-based vaccine design.

ABSTRACT: Identification of viral immune escape mutations that compromise HIV's ability to replicate may aid rational attenuation-based vaccine design. Previously we reported amino acids associated with altered viral replication capacity (RC) from a sequence-function analysis of 487 patient-derived RT-integrase sequences. In this study, site-directed mutagenesis experiments were performed to validate the effect of these mutations on RC. Viral reverse transcripts were measured by quantitative PCR and structural modelling was performed to gain further insight into the effect of reverse transcriptase (RT) mutations on reverse transcription. RT-integrase variants in or flanking cytotoxic T cell epitopes in the RT palm (158S), RT thumb (241I and 257V) and integrase catalytic core domain (124N) were confirmed to significantly reduce RC. RT mutants showed a delayed initiation of viral DNA synthesis. Structural models provide insight into how these attenuating RT mutations may affect amino acid interactions in the helix clamp, primer grip and catalytic site regions.

SUBMITTER: Ojwach DBA

PROVIDER: S-EPMC7931244 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Composite Sequence-Structure Stability Models as Screening Tools for Identifying Vulnerable Targets for HIV Drug and Vaccine Development.

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Predictors of HVTN 503 MRK-AD5 HIV-1 gag/pol/nef vaccine induced immune responses.

Project description:BackgroundPhambili, the Merck (MRK)-Adenovirus Type 5 (Ad5) HIV-1 gag/pol/nef subtype B vaccine study, conducted in South Africa, suspended enrollment and vaccination when companion study, Step, was found non-efficacious. Although the vaccine did not prevent HIV-1 infection or lower viral-load setpoint, immune responses recognized clades B and C HIV-1 subtypes. We investigated predictors of the vaccine-induced antigen-specific immune responses.MethodsVaccine-induced immunogenicity was ascertained by interferon-? ELISpot assays on the first 186 enrolled participants receiving two vaccinations. Analyses, stratified by study arm/sex, were performed on baseline demographics [sex, age, Body Mass Index (BMI), site, Adenovirus Type-5 (Ad5) titer, Herpes Simplex Virus Type-2 (HSV2) status, heavy drinking]. Multivariate logistic regression determined predictors.ResultsOf the 186 participants, 53.7% (n?=?100) were female, median BMI was 22.5 [IQR: 20.4-27.0], 85.5% (n?=?159) were Ad5 seropositive, and 18.8% (n?=?35) drank heavily. All vaccine recipients responded to both clade B (n?=?87; 47%) and/or C (n?=?74; 40%), p?=?0.17. In multivariate analysis, female sex [Adjusted Odds Ratio (AOR): 6.478; p?=?0.0159], overweight/obese BMI (AOR: 0.186; p?=?0.0452), and heavy drinking (AOR: 0.270; p?=?0.048) significantly predicted immune response to clade C for any antigens. A marginally significant predictor of clade C-pol antigen was female sex (AOR: 3.182; p?=?0.0500).ConclusionsSex, BMI, and heavy drinking affected vaccine-induced HIV-1 specific immune responses to clade C antigens. The role of female sex and overweight/obese BMI boosting and suppressing vaccine-induced HIV-1 specific immune responses, respectively, requires elucidation, including any effect on HIV vaccine efficacy, especially in the era of colliding epidemics (HIV and obesity).

| S-EPMC4121165 | biostudies-literature

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