Andre Watson πŸ§¬πŸ’ŠπŸ’‰πŸŽΉ Profile picture
CEO @Ligandal Regenerative Medicine & @BioDefenseFnd: πŸ§ͺπŸ§¬πŸ’ŠπŸ’‰Developing SARS-BLOCKβ„’ #Peptides for #COVID19 #30Under30 #Healthcare & Gene Delivery Nanoscientist
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6 Jan
β€œMost people who recover from COVID-19 develop immune memory that lasts for at least six to eight months, a NIAID-funded study suggests. The findings, published today in Science, are based on analysis of blood samples from 188 people who recovered from infection.” - NIAID
β€œNeutralizing antibodies have generally not correlated with lessened COVID-19 disease severity... Instead, neutralizing antibodies are associated with protective immunity against secondary infection with SARS-CoV-2.”…
β€œWhile sterilizing immunity against viruses can only be accomplished by high-titer neutralizing antibodies, successful protection against clinical disease or death can be accomplished by several other immune memory scenarios.”
Read 20 tweets
30 Dec 20
1/4 SARS-CoV-2 Orf6 appears to hijack nuclear import machinery, inhibiting nuclear translocation of key signaling and cell proliferation molecules such as STAT1 and STAT2. This is another way that SARS-CoV-2 downregulates intracellular immune responses such (e.g. interferon --).
2/4 These findings also meld with prior data demonstrating nuclear translocation of SARS-CoV-2. Coupled, these data suggest that the virus has evolved multiple mechanisms for avoiding both extracellular adaptive immune responses, as well as intracellular immunity / host defenses.
3/4 These findings could also lead to future discoveries about the genesis and pathogenesis of "long COVID" and repeat infections, coupled to the discovery of SARS-CoV-2 building up deep in tissues that are not as accessible to the immune system.
Read 4 tweets
29 Dec 20
After hours at the DMV, at closing, a DMV employee comes out and says β€œAll hope is lost, there is no point, everyone should go home.” I said that’s the most earnest, honest depressing thing I’ve heard all day.

β€œWell, it could be worse. You could have my job,” she says.
β€œSorry, we are at full capacity.” (4:30 PM)
This is the sixth time I’ve tried to go to the DMV to renew my license.
Read 4 tweets
21 Jul 20
We took this image of CRISPR-Cas9 (green) being delivered to a T cell using our targeting peptide tech, which was the first demonstration of CRISPR delivery to a primary human T cell with a non-viral nanocarrier as of 2018, AFAIK. We achieved 34% editing.

Credit: @Ligandal
Green: CRISPR-Cas9 ribonucleoprotein delivered via peptide nanocarriers
Blue: nucleus
Red: cytosol
Scale bar: 500 nanometers
Imaging: super-resolution microscopy
Using this sort of tech, you can target and manipulate specific cell types with arbitrary genetic code, both in permanent (e.g. CRISPR-Cas9) and temporary (e.g. mRNA) ways. T cell editing is particularly relevant in the fields of immuno-oncology and autoimmune diseases.
Read 4 tweets
20 Jul 20

My ACE2 cloak hypothesis is shifting a bit. Soluble and membrane-bound ACE2 is clearly not fully saturating all exposed neutralizing antibody sites, and some B cells are binding. Still, ACE2 cloaking suggests that small numbers of virus get fully cloaked.
Alternatively to the ACE2 cloaking, the virus still has some shielding mechanisms alternative to that including glycosylation and going from closed to open conformations. In β€œopen” state, ACE2 would bias the thermodynamics of B cell binding to the spike protein...
...and the subsequent antibody-generating response, to be preferential to other sites. Doesn’t mean that B cells won’t stick to neutralizing site at all.

This is in a large part driven by ACE2 existing both as a soluble and membrane-bound protein.
Read 17 tweets
25 Jun 20
Why has @BARDA / @HHSGov suspended its funding for immunomodulators and therapeutics that "improve the clinical response and/or resolution of symptoms associated with... viral respiratory infections" as well as for "pre- and post-exposure prophylaxis" approaches?
When considering the flaws in spike protein vaccine development, and that @BARDA has shelled out >$2Bn to just five companies developing spike protein vaccines, it almost seems like no one wants to fund preventative or effective therapeutic approaches to this virus. Why is that?
"[T]herapeutics... or the use of post-event prophylaxis will be the preferred strategy... Priority will be placed on [medical countermeasures] that focus on post-event prophylaxis or post-exposure treatment."
Read 15 tweets
11 Jun 20
I recommend reading about immunological synapses to better understand how various immune cells (particularly T cells and NK cells) can grab onto antigens and aid B cells in maturing higher affinity BCRs and antibodies, as well as encourage division…
CD8+ β€œKiller” T cells:…
B cells and CD4+ Th cell mediated antibody formation and B cell activation:…
Read 17 tweets
6 Jun 20
I bought a one-way ticket to Silicon Valley when I was 21. I had just finished my bachelor’s in Biomedical Engineering at Rensselaer Polytechnic Institute where I worked with TALENs and created a gene editing, nanoparticle-based delivery system for editing mice.
The first years were tough. People would always ask, β€œwhat makes you think you can...” style questions. VCs would play games. It was like Silicon Valley, the TV show.
In 2017 we raised a seed round. With that cash we built a state-of-the-art, highly automated lab capable of everything from peptide synthesis to fluid handling automation and automated cell imaging, with integrated data outputs.
Read 40 tweets
30 May 20

"[M]ost initial efforts to generate subunit vaccines against SARS-2 have also focused on the... S protein and its receptor-binding domain. This effort may prove to be more difficult for SARS-2 than for SARS-1..."
"The affinity of SARS-2 S protein for its receptor ACE2 is approximately 15 nMβ€”over 20 times tighter binding than that observed by SARS-1 S protein (Wrapp et al. 2020; Yan et al. 2020)."…
In actuality, SARS-CoV-2 has approximately 700 pM binding to ACE2. Some studies estimate that it's closer to 5 pM. The problem is even worse.
Read 5 tweets
29 May 20
These issues may become even further accentuated 6 months or longer after the vaccination, as small titers of neutralizing antibodies disappear from the blood.

Furthermore, many people will develop immunity to this vaccine itself, which doesn’t relate to immunity against SARS.
By using viruses to produce portions of another virus (in this case and Oxford’s case, an adenovirus to make spike proteins of SARS2), you also make it nearly impossible to repeatedly dose and administer a new vaccine when SARS2 mutates and evolves.
Read 10 tweets
29 May 20
β€œBut scientists make a distinction between antibodies that simply bind to the spike protein and those that prevent infectionβ€”so-called neutralizing antibodies. They believe that developing neutralizing antibodies is a crucial step...”…
@RLCscienceboss πŸ™πŸ€Ÿ
There are major issues with spike protein vaccines.
I have explained in further detail here.

Meanwhile, @BARDA channels $400M+ into these flawed approaches, while essential technologies to properly vaccinating and creating therapeutics against #SARSCoV2 are held back and not funded.
Read 6 tweets
27 May 20
Here is the virus in "closed" (teal) and "open" (green) form. In "open" form, it binds to ACE2. ACE2 also blocks the ideal neutralizing antibody sites, and binds with extremely high, picomolar affinity (similar binding strength to many strongly binding antibodies).
The "closed" variant is the Veesler Lab cryo-EM structure (…). The "open" variant is the SWISS-MODEL simulated spike protein structure (…). I did the ACE2 docking myself, before we had binding data of pocket.
Ligandal peptide nanoscaffolds are designed to interfere with ACE2-spike binding, while also promoting a strong immune response against the correct receptor-binding domain component for antibody generation. This means that you can give the nano-scaffold before or after infection.
Read 15 tweets
26 May 20
This is really not good. SARS-infected cells are becoming MHC-negative. This means that chewed up pieces of the virus are not appearing on the cell surface for T cells to be able to recognize.
While innate immune cells (NK cells) actively clear cells that are MHC-, this is a big blow to adaptive immunity, especially when coupled with antibody avoidance techniques the virus has.
β€œ[T]he killer T cells used in the study were not effective at eliminating the virus in infected cells. When the scientists took a closer look they found that a molecule known as major histocompatibility complex, or MHC, was missing.”
Read 4 tweets
18 May 20
I think there is a lot of confusion about what immunity means.

Adaptive immunity, which is what you hope to develop when you’re vaccinated, trains your B cells and T cells to recognize pathogens or other antigens.
B cells form responses to proteins β€œwith shape.” This means that the protein, such a virus, will present an outer portion of itself to the B cells. The B cells that bind the most strongly will mature and grow to have even stronger binding. This is through B cell receptors.
B cell receptors get released from the B cell, and become antibodies.
Read 9 tweets
15 May 20
#Sorrento Therapeutics is claiming that their antibody is 100% effective and will cure the virus.... but didn’t study ACE2 protein coronas and did their study in vitro. You can take a relatively crappy antibody, saturate the virus, and show β€œ100% inhibition.” #PumpandDump
Read 4 tweets
11 May 20
We know that the SARS-CoV-2 virus has evolved to bind to the ACE2 receptor approximately 10x stronger than SARS-CoV-1. ACE2 also circulates in the blood. There are several mechanisms whereby ACE2 will displace antibodies.

Let me elaborate.
Here is a great example to start off, from From Ju, B., Zhang, Q., Ge, X., Wang, R., Yu, J., Shan, S., ... & Ge, J. (2020). Potent human neutralizing antibodies elicited by SARS-CoV-2 infection. BioRxiv.
"Here, we report on the isolation and characterization of 206 RBD-specific monoclonal antibodies (mAbs) derived from single B cells of eight SARS-CoV-2 infected individuals."
Read 20 tweets
11 May 20
If anyone wants to investigate for themselves, here are all of the similar sequences to #SARSCoV2, #SARSCoV1, and #DISEASEXXX, a dog coronavirus. Note that #MERSCoV is ~64% similar to SARS-COV-2 and SARS-CoV2 is 80% similar to SARS-CoV-1.

These were download from @NIH #GenBank.
#SARSCoV1 ALIGN NCBI Blast_NC_004718_SARS coronavirus, complete genome…
Read 13 tweets
11 May 20
As a scientist, I'd like to note that it's impossible to study a bat coronavirus for 7 years within a research lab where they were known to recombine different viral fragments, and not end up having evolution happen that perhaps wouldn't have happened in the wild. Just saying.
Recombining viruses, you say? Wuhan, 2017.

Hu, B., Zeng, L. P., Yang, X. L., Ge, X. Y., Zhang, W., Li, B., ... & Luo, D. S. (2017). Discovery of a rich gene pool of bat SARS-related coronaviruses provides new insights into the origin of SARS coronavirus. PLoS pathogens, 13(11).
Read 6 tweets
8 May 20
#SARSCoV2 There are several kinds of #vaccines, whereby all share the goal of generating adaptive #immunity via 1) #antibodies via B cells, and 2) T-cell receptors (#TCRs) via T cells:
1) live-attenuated, where you produce an actual #virus in an egg or cell line
2) #recombinant, where you introduce #DNA into yeast, bacteria, or cell lines β€” you produce pieces of the #virus #proteins, then either administer them as-is or typically by linking them to immunogenic substrates like albumin, BSA and KLH
Read 6 tweets
29 Apr 20
(1/6) Most drugs are not effective at treating #COVID, and do not address the root-cause symptoms. #Remdesivir is one such exampleβ€”the drug mimics #RNA, and gets incorporated into the viral RNA transcripts preferentially versus human RNA transcripts.
(2/6) Mechanistically, this drug was promsising. However, in today’s @TheLancet paper, "#Remdesivir in adults with severe #COVID-19: a randomised, double-blind, placebo-controlled, multicentre trial," findings are inconclusive at best, and damning at worst:
1) The study enrolled already-hospitalized patients with pneumonia, with <94% oxygen saturation, who were already hospitalized
2) They measured clinical improvement for 28 days
3) "#Remdesivir use was not associated with a difference in time to clinical improvement"
Read 6 tweets