Interesting about what concentrations of LL requir
Post# of 148168
Obviously, it works great for HIV @350 mg and 700 mg to block HIV from binding.
I imagine the RO assay information was done as from the 2010 paper:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2856743/
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CCR5 receptor occupancy was assessed by comparing the numbers of lymphocytes that stained positive for binding of PE-labeled PRO 140 pre- and post-treatment.
Using PE fluorescent labeling / "stain" of lymphocytes may be something the FDA didn't go for in rejecting the BLA? It was suggested that InCellDx did the RO work for HIV, but he says he did not.
Anyways, the RO data (using the above method) in the 2010 IV LL paper showed 70-80% of lymphocytes had bound CCR5 at baseline. After LL 5 or 10 mg/kg IV, it went to 95-100% occupied at 1-2 days, and stayed there for 30 days, and longer depending on dose.
Regarding your queries, as always, I love to speculate about things of which I know not!
First, I wonder about the differences in methods used in the 2010 paper, and the method BP uses now. Wish I understood what was different about the methods. I think BP uses LL, labels it with some kind of marker (fluorescent), and thus sees what % of different cell types (using another label/tag to catch, say, cells with CD4) are able to bind the labeled LL. If only 10% can bind, then 90% of receptors are occupied. Uses flow cytometry and I forget he gave a nice presentation to the makers of the equipment he uses for the assays.
So, I wonder if the 2010 paper compares to the recent LL work by Patterson on RO. I think they might be different, else FDA wouldn't have a problem with the CYDY RO testing for HIV (while InCellDx RO assay seems FDA approved).
Regarding
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One question I have is why does it take two weeks to achieve 100% RO in the Patterson results?
And I wonder in the subQ case for covid, how does the RO level not hit 100% in a day or two?
Besides the RO tests being different potentially (stain vs. flow cytometry) and that the only RO data we saw for HIV was IV but for Covid was given SQ, BP mentioned there would be some turnover of CCR5 receptors as well as new lymphocytes created, and that's why need to give another dose.
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At day 8 the LL concentration is going down, but somehow between day 8 and day 14 the RO occupancy rises from 80% to 100%. How is that possible?
I think the simple explanation is that they give another dose at day 8. Unless you are talking about some other RO data?
Wish someone who understood RO assays could clue me/us in.
Maybe I should read this and other articles:
https://onlinelibrary.wiley.com/doi/10.1002/cyto.b.21259