Thread by @adamhamdy

1. The @Ligandal antidote to #SARSCoV2 has been getting a lot of attention, but some people are having difficulty understanding how it works and what makes it so promising, so here's a Saturday explainer.

https://twitter.com/nanogenomic/status/1291526537280466945

2. There have been many questions about immunity to human coronaviruses and whether vaccines will prompt a long-term protective immune response to #SARS_CoV_2. @edyong209 does a great job of explaining the vagaries of immunity.

theatlantic.com/health/archive…

3. @Ligandal opted for an approach that doesn't rely on the human immune system to be effective.

The #SARSCoV2 virus infects human cells via the ACE2 receptor. Here's a computer simulation with the ACE2 receptor in red and the virus in green.

Big bully 🦠

4. Peptides are chains of amino acids, the building blocks of life. Book smart people like @nanogenomic can sequence amino acids and design new chains, creating synthetic peptides, which can be used in vaccines and treatments.

5. They can also be used to create nanoscaffolds. Tiny structures that perform specific functions.

In this case, the @Ligandal peptide, SARS-BLOCK, binds with ACE2 and blocks the virus from being able to infect cells. The SARS-BLOCK peptide is the plucky fellow in purple.

6. It acts like a shield, preventing infection of the cell by the virus, hence the BLOCK in SARS-BLOCK. I preferred the name S.H.I.E.L.D, but @Marvel...

The experiments conducted by @nanogenomic @enhancerleo & @lab_stroud demonstrate the peptide does its job.

7. Great, right?

It gets better. Not only does the peptide block infection, thanks to some clever engineering, it binds with neutralising antibodies, which means it can help train the immune system to clear the virus more effectively.

8. This makes SARS-BLOCK unique as a combination treatment and vaccine. It should be able to be taken by healthy people as a prophylactic or given to those who are ill as a treatment. This tiny peptide packs a punch🥊

9. Ligandal's approach neutralises the virus directly. It doesn't rely on our immune system, which seems to struggle with coronaviruses, and #SARSCoV2 in particular. The peptide is room temperature stable and has a long shelf life, meaning it can be deployed globally.

10. Some people struggle to picture how a tiny peptide can protect all our ACE2 receptors and how it will be administered. The answer to that is to think about the virus. Tiny virus particles infect the nose or mouth and manage to travel around the body.

11. Here are the #SARSCoV2 virons on a human cell. They're tiny, but the SARS-BLOCK peptide is even smaller. It uses the same pathways as the virus to travel the body, & because it is a nano baby compared to the hulking virus, it needs to be administered in tiny quantities.

12. Ligandal believes SARS-BLOCK will be capable of being administered orally, via an intra-nasal spray or intravenously. We'll know more soon. As an amino acid sequence, SARS-BLOCK will eventually leave the body, so, like the Littlest Hobo, it will do its job and just roll on.

13. This may change the way we think about vaccines - as a regular supplement for a given period of exposure risk or until a viral disease has been eradicated. And yes, the technology behind SARS-BLOCK has potential to neutralise other viral diseases.

14. SARS-BLOCK is an ingenious invention and @nanogenomic deserves many congratulations for designing and delivering it. So where do we go from here? Well, the lab results are very promising, but Ligandal has got to trial SARS-BLOCK in actual immune systems.

15. So the next step is more experiments to understand dosage and prove safety & efficacy. At the same time, the team will be figuring out production and distribution at scale.

16. I hope this helps explain why SARS-BLOCK is such a promising solution to the #COVID19 pandemic. If you'd like to find out more, dive into the paper written by the scientific team who conducted the experiments:

biorxiv.org/content/10.110…