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Platelet EVs contain an active proteasome involved in protein processing for antigen presentation via MHC-I molecules

2021· article· en· 90 citations· W3185696431 on OpenAlex· 10.1182/blood.2020009957

Why is this work in the frame?

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

Canadian affiliationAn author listed a Canadian institution. This is the only route the usual frame has.
Canadian funderA Canadian agency funded it. The work may carry no Canadian affiliation at all.

Full frame distilled prediction

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.

Candidate categories
none
Consensus categories
none
Domain
Candidate signal: noneConsensus signal: none
Study design
Candidate signal: Bench or experimentalConsensus signal: Bench or experimental
Genre
Candidate signal: EmpiricalConsensus signal: Empirical
Teacher disagreement score
0.122
Threshold uncertainty score
0.558
Validation status
machine_predicted_unvalidated · codex-gemma-dda1882f352a

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0000.000

Machine scores (provisional)

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

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.

Opus teacher head0.019
GPT teacher head0.290
Teacher spread
0.271 · how far apart the two teachers sit on this one work
Validation status
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Abstract

In addition to their hemostatic role, platelets play a significant role in immunity. Once activated, platelets release extracellular vesicles (EVs) formed by the budding of their cytoplasmic membranes. Because of their heterogeneity, platelet EVs (PEVs) are thought to perform diverse functions. It is unknown, however, whether the proteasome is transferred from platelets to PEVs or whether its function is retained. We hypothesized that functional protein processing and antigen presentation machinery are transferred to PEVs by activated platelets. Using molecular and functional assays, we found that the active 20S proteasome was enriched in PEVs, along with major histocompatibility complex class I (MHC-I) and lymphocyte costimulatory molecules (CD40L and OX40L). Proteasome-containing PEVs were identified in healthy donor blood, but did not increase in platelet concentrates that caused adverse transfusion reactions. They were augmented, however, after immune complex injections in mice. The complete biodistribution of murine PEVs after injection into mice revealed that they principally reached lymphoid organs, such as spleen and lymph nodes, in addition to the bone marrow, and to a lesser extent, liver and lungs. The PEV proteasome processed exogenous ovalbumin (OVA) and loaded its antigenic peptide onto MHC-I molecules, which promoted OVA-specific CD8+ T-lymphocyte proliferation. These results suggest that PEVs contribute to adaptive immunity through cross-presentation of antigens and have privileged access to immune cells through the lymphatic system, a tissue location that is inaccessible to platelets.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

The record

Venue
Blood
Topic
Platelet Disorders and Treatments
Field
Medicine
Canadian institutions
University of TorontoCentre Hospitalier de l’Université de MontréalUniversité de MontréalUniversité LavalTranslational Research in OncologyCentre hospitalier universitaire de Québec
Funders
MitacsSchweizerischer Nationalfonds zur Förderung der Wissenschaftlichen ForschungInstitut National de la Santé et de la Recherche MédicaleFonds de Recherche du Québec - SantéArthritis SocietyCanadian Blood ServicesAgence Nationale de la RechercheVetenskapsrådetNational Science Foundation
Keywords
PlateletAntigen presentationAntigen processingAntigenMHC class IBiologyImmune systemImmunologyCD8Major histocompatibility complexCross-presentationCell biologyT cell
Has abstract in OpenAlex
yes