Presence of Host ICAM-1 in Human Immunodeficiency Virus Type 1 Virions Increases Productive Infection of CD4 <sup>+</sup> T Lymphocytes by Favoring Cytosolic Delivery of Viral Material
Bibliographic record
Abstract
Although there is now convincing evidence that the infectivity of human immunodeficiency virus type 1 (HIV-1) is increased by incorporation of host intercellular adhesion molecule 1 (ICAM-1) in budding virions, the exact mechanism(s) through which ICAM-1 can so significantly affect HIV-1 biology remains obscure. To address this question, we focused our attention on the most proximal events in the virus life cycle. We made comparative analyses to estimate attachment and internalization of isogenic HIV-1 particles either lacking or bearing host-derived ICAM-1. Using attachment-and-entry assays and confocal fluorescence microscopy, we found that virus binding and uptake were both markedly enhanced by insertion of ICAM-1 within the virus envelope when PM1 lymphoid cells and primary human cells (i.e., peripheral blood lymphocytes and purified CD4(+) T cells) were used as targets. Moreover, ICAM-1-bearing virions entered cells with faster uptake kinetics than viruses devoid of ICAM-1. Experiments conducted with fully competent viruses further confirmed the positive effect of virion-anchored host ICAM-1 on HIV-1 replication. Interestingly, subcellular-fractionation assays revealed that ICAM-1 incorporation modifies the HIV-1 entry route by increasing the level of viral material released in the cytosol, a process of internalization known to be mediated mainly by pH-independent membrane fusion and to result in productive infection. A virion-based fusion assay confirmed that the acquisition of ICAM-1 increases the efficiency of productive HIV-1 entry in primary CD4(+) T lymphocytes. These observations provide new insights into how interactions other than those with gp120 and CD4-coreceptor complex can modulate the process of productive HIV-1 infection in CD4(+) T lymphocytes, a cell target highly relevant to HIV-1 pathogenesis.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".