Question explored with the scientific record
Conversation so far
- 1 Discuss the implications of 250x fold elevations of spike protein detectable in a patient's exosomes, with zero spike detectable in plasma or immune cells + a private exchange
- 2 Maugeri et al 2019 note that transcytosis is consistent with their findings on mRNA-LNP delivery. Is this transfection, rather than transcytosis? + a private exchange
- 3 How do later studies explain mRNA-LNP crossing the BBB? + a private exchange
- 4 You stated earlier that, "Transcytosis would mean the intact LNP crosses the BBB and then transfects brain cells (neurons, astrocytes, microglia) on the other side. Transfection of the BBB means the LNP is taken up by the endothelial cells that line the brain's blood vessels, the mRNA is translated inside those cells, and the protein product is what gets released into the brain." Following up -"what exact evidence do they use to rule out intact LNP transcytosis and why does it matter? + a private exchange
- 5 Either way, in this patient's case 2P S can be delivered across the BBB, by process of transcytosis at least. Explain the likely effects of such a process + a private exchange
- 6 Tell me about the likely implications for disease-injury processes once 2P spike has been transcytosed across the BBB. + a private exchange
- 7 Which specific injury mechanisms are most likely after BBB crossing? + a private exchange
- 8 to what extent are these pathways consistent with neuro-inflammation and, in effect, autoimmune encephalitic processes? + a private exchange
- 9 How do these mechanisms differ between infection-related encephalitis and autoimmune? + a private exchange
- 10 Please share more about The 2025 PANS/PANDAS review - with references - that shows autoantibodies to striatal cholinergic interneurons, Th17-driven BBB disruption, and microglial activation. What were the symptoms specificially associated with such striatal cholinergic interneurons + a private exchange
- 11 How do infection-related encephalitis mechanisms compare to BBB/Th17 autoimmunity? + a private exchange
- 12 To what extent can these Th17-autoantibody mechanisms be characterised as T and B cell mediated humoral autoimmunity + a private exchange
- 13 What evidence would distinguish humoral autoimmunity from innate Th17? + a private exchange
- 14 You state, "if a patient has humoral autoimmunity, with high titres of serum autoantibodies against known self-antigens." Such as what? + a private exchange
- 15 Hmm. This process described above is more likely to present with humoral autoimmunity that is ANA and ENA negative ie not nuclear autoimmunity. + a private exchange
- 16 But, as established before, such patients have no N in exosomes. It is not WT, but 2P spike in play. + a private exchange
- 17 What studies compare 2P spike vs wild-type spike in exosome loading? + a private exchange
- 18 iF the evidence does show is that spike protein from natural infection is actively packaged into exosomes, how long can it persist given the relative fragility of the molecule compared with the 2P mutated version? + a private exchange
- 19 You say, "For spike to still be in circulating exosomes five years later, either the protein must be continuously produced from a persistent mRNA reservoir, or it must be recycled through cells repeatedly." Recycled by transcytosis. My point entirely.
- 20 the mechanism would require continuous production or near-total recycling failure. Pse examine both scenarios, and if transcytosis recycled spike, what cell pathway would recreate it long-term?
- 21 With respect, Bansal et al 2021 demonstrated exosome titres that were not zero after 4 months. No follow ups on trial subjects beyond 4 months. Absence of evidence.......etc
Answered on this page ↓
With respect, Bansal et al 2021 demonstrated exosome titres that were not zero after 4 months. No follow ups on trial subjects beyond 4 months. Absence of evidence.......etc
The short version: the evidence here does not contain a single study that measures spike in exosomes at any time point, let alone at 4 months, so the question cannot be answered from these records.
The retrieval surfaced 23 records. None of them measure spike protein in exosomes after mRNA vaccination. None of them follow subjects for 4 months. None of them quantify exosome-associated spike titers. The Bansal et al 2021 study you name is not among them. The evidence here is entirely about exosome biogenesis pathways [8, 9, 11, 13, 14, 17], spike protein structure [1, 4, 5], and vaccine constructs that are not the mRNA platform [2, 3]. These records describe how exosomes are made and sorted, but they do not answer whether spike persists in them at 4 months.
The two scenarios you laid out are both speculative against this evidence base. Continuous production from a persistent mRNA reservoir is the more parsimonious mechanism, but the evidence here does not document mRNA persistence beyond the designed expression window for standard mRNA vaccines. The recycling-failure scenario would require a clearance defect that the evidence here does not describe. The endosomal recycling compartment (ERC) pathway exists [8, 9], but no record here measures what fraction of internalized exosomal spike escapes degradation.
My call: neither scenario is supported by the evidence in this retrieval. The study that would settle this has not been done, or at least was not retrieved. Confidence: low, because the relevant measurement was never made in any record here.
Sources used 11
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Different residues in the SARS-CoV spike protein determine cleavage and activation by the host cell protease TMPRSS2
This study investigates the specific residues in the SARS-CoV spike protein that determine its cleavage and activation by the host cell protease TMPRSS2, revealing that residue R667 is essential for cleavage while R797 is critical for activation.
DOI: 10.1371/journal.pone.0179177 -
Recombinant Modified Vaccinia Virus Ankara Expressing the Spike Glycoprotein of Severe Acute Respiratory Syndrome Coronavirus Induces Protective Neutralizing Antibodies Primarily Targeting the Receptor Binding Region
A recombinant Modified Vaccinia Virus Ankara (ADS-MVA) expressing the full-length SARS-CoV spike protein induces potent neutralizing antibodies in mice, rabbits, and Chinese rhesus macaques, maps the neutralizing epitope to the ACE2-binding region of the spike, and provides evid…
DOI: 10.1128/jvi.79.5.2678-2688.2005 -
THE RECOMBINANT BACTERIA LACTOCOCCUS LACTIS EXPRESSING SARS-COV-2 SPIKE PROTEIN OR ITS RECEPTOR-BINDING DOMAIN ELICITS AN IMMUNE RESPONSE FOLLOWING ORAL IMMUNISATION OF RATS
Recombinant Lactococcus lactis strains expressing SARS-CoV-2 spike protein or its receptor-binding domain were constructed and orally administered to rats, leading to expression of the antigens in bacteria and elicitation of SARS-CoV-2 spike RBD–specific serum IgG, with the high…
DOI: 10.11134/btp.3s.2024.17 -
N- and O-Glycosylation of the SARS-CoV-2 Spike Protein
The study precisely maps site-specific N- and O-glycosylation on the SARS-CoV-2 spike protein expressed in HEK293 cells using advanced LC-MS/MS and ion mobility techniques, revealing extensive N-glycosylation with LacdiNAc and polyLacNAc motifs and identifying eight additional O…
DOI: 10.1021/acs.analchem.0c03173 -
Computational Insights into the Conformational Accessibility and Binding Strength of SARS-CoV-2 Spike Protein to Human Angiotensin-Converting Enzyme 2
This computational study analyzes how the SARS-CoV-2 spike protein visits ACE2-accessible conformations and binds ACE2 more strongly at the RBD level than SARS-CoV, yet exhibits fewer ACE2-accessible states and higher energy barriers for spike opening, identifying key residues a…
DOI: 10.1021/acs.jpclett.0c02958 -
Syntenin-ALIX exosome biogenesis and budding into multivesicular bodies are controlled by ARF6 and PLD2
This study identifies ARF6 and its PLD2 effector as key regulators of syntenin-containing exosome biogenesis by controlling intraluminal vesicle budding in multivesicular bodies, linking late-endosomal trafficking and EGFR degradation to exosome production while showing no effec…
DOI: 10.1038/ncomms4477 -
ALIX- and ESCRT-III–dependent sorting of tetraspanins to exosomes
This study identifies an activated form of ALIX that recruits ESCRT-III to LBPA-rich late endosomes, revealing an LBPA- and ALIX-dependent alternative pathway for ESCRT-III–mediated sorting that selectively loads tetraspanins CD9/CD63/CD81 into exosomes and stimulates exosome bi…
DOI: 10.1083/jcb.201904113 -
Understanding extracellular vesicle diversity – current status
This review synthesizes current understanding of extracellular vesicle diversity, detailing the distinctions between exosomes and shed microvesicles, the mechanisms governing their biogenesis and cargo selection, the challenges and strategies for purification and characterizatio…
DOI: 10.1080/14789450.2018.1537788 -
DENN domain-containing protein FAM45A regulates the homeostasis of late/multivesicular endosomes
The study characterizes FAM45A as a non-classical DENN-domain protein that localizes to late/multivesicular endosomes in human cells, regulates endosome positioning and maturation, delays EGFR trafficking from early to late endosomes, and impairs secretion of specific exosome su…
DOI: 10.1016/j.bbamcr.2019.02.006 -
Proteolipidic Composition of Exosomes Changes during Reticulocyte Maturation
The study profiled how the proteolipidic composition of exosomes released by rat reticulocytes changes during in vitro maturation, revealing sequential activation of distinct exosome biogenesis pathways and corresponding shifts in protein and lipid cargo.
DOI: 10.1074/jbc.M111.257444 -
Analysis of ESCRT functions in exosome biogenesis, composition and secretion highlights the heterogeneity of extracellular vesicles
Using an shRNA RNAi screen targeting 23 ESCRT components in MHC II–expressing HeLa cells, followed by biochemical and immuno-EM analyses, the study reveals that specific ESCRT members regulate exosome secretion and cargo composition, uncovering substantial heterogeneity among ex…
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