M184I/V substitutions and E138K/M184I/V double substitutions in HIV reverse transcriptase do not significantly affect the antiviral activity of EFdA
Bibliographic record
Abstract
BACKGROUND: 4'-Ethynyl-2-fluoro-2'-deoxyadenosine (EFdA) is a potent nucleoside analogue inhibitor of HIV that has an unusually long half-life. Cell culture selections with either EFdA or lamivudine using both subtype B and non-B clinical isolates selected the M184I/V substitutions in reverse transcriptase (RT). Unlike lamivudine, however, EFdA retained significant activity against viruses containing the M184I/V substitutions. In other clinical trials that evaluated rilpivirine together with emtricitabine in first-line therapy, the emergence of both the M184I/V and E138K mutations in RT was demonstrated. Moreover, the M184I/V and E138K substitutions were shown to be compensatory for each other with regard to both efficiency of RT activity and viral replicative capacity. This creates concern that E138K might emerge as a compensatory mutation for M184I/V in the aftermath of the use of EFdA. OBJECTIVES: We wished to determine whether the E138K mutation in HIV RT together with M184I/V would compromise the activity of EFdA. METHODS: Recombinant viruses containing the M184I/V and/or E138K substitutions were generated by site-directed mutagenesis and evaluated in tissue culture for susceptibility to various nucleoside compounds, including EFdA. RESULTS: Susceptibility to EFdA was retained in M184I/V viruses that also contained the E138K substitution. Moreover, the E138K substitution was not generated in these studies under selection pressure with EFdA. CONCLUSIONS: These findings help to alleviate concern that EFdA may not be active against viruses that contain both the M184I/V and E138K substitutions in RT.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".