Selection in culture of HIV resistance to dolutegravir by mutations at integrase positions R263K and H51Y that diminish viral replication fitness
Bibliographic record
Abstract
Purpose of the study We selected for resistance in tissue culture against dolutegravir (DTG), a second‐generation HIV integrase strand transfer inhibitor, which is now in phase 2/3 clinical trials, in order to try to characterize the resistance profile of this compound. Methods HIV‐1 of different subtypes was grown in both MT‐2 cells and peripheral blood mononuclear cells over protracted periods, with the concentration of DTG being incrementally increased from an initial concentration of 0.05 nM, i.e. 4 times less than the EC50. After a total of 6 months of growth, a final drug concentration of 50–100 nM was achieved, beyond which virus could no longer be grown. Viral DNA was then sequenced to reveal the presence of mutations that might confer resistance to DTG. The biological relevance of these mutations was confirmed through site‐directed mutagenesis experiments in which individual mutations or combinations of mutations were studied in comparison with wild‐type (wt) virus in tissue culture and with recombinant HIV integrase enzyme in biochemical assays. Summary of results The most common integrase resistance mutation to arise in subtype B and recombinant A/G viruses was R263K followed by H51Y. In the case of subtype C viruses, the most common mutation was G118R followed by H51Y. The presence of R263K alone conferred an approximate 3–6‐fold level of resistance to DTG in culture, a 30% drop in levels of recombinant integrase strand transfer activity, as well as an approximate 20–30% loss in viral replicative capacity. Biochemical experiments indicated that the t½ residency times of DTG for subtype B and C viruses for wt integrase were 26 h and 38 h, respectively, and for R263K, 16h and 22h, respectively. In contrast, H51Y by itself did not significantly affect either strand transfer activity or resistance to DTG. However, the combination of R263K together with H51Y led to an increase in levels of DTG resistance to about 15‐fold accompanied by an ~50% loss in both viral replication capacity and integrase strand transfer activity. Conclusions R263K and H51Y can combine to augment levels of resistance to DTG yet result in a more severe attenuation of viral replication capacity and integrase strand transfer activity than R263K alone. These data suggest that viruses containing both mutations may be at a severe replicative disadvantage and help to explain why primary resistance to DTG is so rare to arise in clinical studies performed to date.
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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) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".