Characterization of HIV-1 particles co-purified with three extracellular vesicle subtypes from the Raji CD4 DCIR cell line, a hybrid model of CD4 T cells and dendritic cells
Bibliographic record
Abstract
Abstract Background HIV-1 proteins and RNA are packaged into extracellular vesicles (EVs) through interaction with the multivesicular endosomes of the EV biogenesis machinery. This interaction also allows functional or abortive viruses to exit the cells as exosomes, microvesicles or apoptotic vesicles. HIV-1 viral particles and EVs share significant similarities in size, composition, and molecular cargo, making their separation challenging. Current HIV-1 purification methods neglect the effects of EVs on virus infectivity, which could influence experiment outcomes. Here, we co-characterized HIV-1 particles co-purified with exosomes, microvesicles and apoptotic vesicles to determine their impact on HIV-1 infection. Methods The HIV-infected Raji CD4 DCIR cells’ supernatants were harvested 2 and 8 days after infection. The 2-day supernatant was treated with proteinase K to discard viral protein and HIV-1 RNA associated with proteins outside the EVs. The supernatants were fractionated into three pellets by differential centrifugation. The 3K pellet contained the largest EVs, such as apoptotic vesicles. The 17K and 100K pellets were respectively associated with microvesicles and exosomes. EVs and viral particles were co-characterized for their host and viral contents and the pellets obtained after 8 days post-infection were tested for infectivity. Results Proteinase K treatment notably lowered HIV-1 RNA concentration in the EV pellet and did not affect viral p24 capsid protein concentration. The p24 protein was mostly found in the 17K pellet and HIV-1 RNA was the most abundant in the 100K pellet for both 2- and 8-day productions. Nevertheless, the 3K pellet had the highest infectivity when cells were infected with an equal quantity of virus (measured by p24) from each pellet. Conclusion Productively infected cells released functional viruses in the three EV subtypes, each exerting a distinct effect on virus infectivity. For future experiments, the presence of EVs in viral preparations should be taken into account, as they influence the progression of HIV-1 infection. Highlights HIV-1 RNA and p24 capsid protein are packaged within apoptotic vesicles, microvesicles and exosomes released by Raji CD4 DCIR cells. Infectious particles co-precipitated with the 3K pellet from Raji CD4 DCIR cells are more infectious than other viruses associated with other EV pellets.
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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 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".