Comment by walterbell | Hacker News Reader

Comment by walterbell | Hacker News Reader

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> the immune system has an array of other defenses... including antibodies that attack other parts of the virus, and, importantly, T-cells that attack the infected cells the virus hijacks in order to replicate. “What we’re seeing is that these variants don’t seem to affect T-cell immunity all that much and they [the T-cells] seem to be as effective in recognizing these variants as they do the original virus”

People with healthy immune systems, who have been exposed to SARS1 and other coronaviruses, have active T-cell defenses which recognize SARS-Cov-2 even without a vaccine.

> SARS-CoV-2 induces robust memory T cell responses in antibody-seronegative and antibody-seropositive individuals with asymptomatic or mild COVID-19, https://www.biorxiv.org/content/10.1101/2020.06.29.174888v1.... (June 2020)

> ..some people who have not been exposed to SARS-CoV-2 have preexisting reactivity to SARS-CoV-2 sequences ..previous exposure to widely circulating common cold coronaviruses might be involved .. preexisting reactivity against SARS-CoV-2 comes from memory T cells and that cross-reactive T cells can specifically recognize a SARS-CoV-2 epitope as well as the homologous epitope from a common cold coronavirus, https://science.sciencemag.org/content/370/6512/89 (Oct 2020)

Prior HN discussion on T-cells: https://hn.algolia.com/?prefix=true&query=t-cell

I have done my PhD on T cell activation. The persistent focus of the media and even some of the science community on Antibody induced immunity was completely beyond me. T cells were largely simply ignored even though they play such a crucial role in the body’s immune response.

Antibodies seem to be a concept much easier to grasp. Maybe we should call T cells "Police Cells or "Anti-Cells" instead. You know, some marketing might help...

T cell activation is readily misunderstood even among some cell biologists. There's a lot of people in life science academia who desperately need to update their knowledge about the recent discoveries in Immunology.

Are vaccines necessary for someone who has had covid? If it was absolutely necessary to prioritise those who don’t have any immunity at all, is there a test that can help identify with that?

The FDA recently approved the first test of T-cells to determine whether someone was previously infected by Covid, https://abcnews.go.com/Health/fda-authorizes-cell-test-game-...

>The test is administered via blood draw. T-cell DNA is then extracted and sequenced with Microsoft's artificial intelligence, mapping out the immune system's "massive black box" data into navigable science, researchers say.

> Maybe we should call T cells "Police Cells or "Anti-Cells" instead. You know, some marketing might help...

Sad, but probably very true...

Good idea! Infographic, logo, spokesperson.

They were also featured in Once Upon a Time... Life... https://static.wikia.nocookie.net/once-upon-a-time-life/imag...

(from https://once-upon-a-time-life.fandom.com/wiki/Lymphocytes)

Thanks!

And a cute branded website, treat it like one of those named exploits perhaps?

Yep, it is competing for research resources and media attention.

This opinion piece used the phrase "T Cells: Warriors of SARS-CoV-2 Infection", https://www.cell.com/trends/immunology/fulltext/S1471-4906(2...

UK Science Museum 2-pager with diagrams (https://www.immunology.org/public-information/bitesized-immu...) and UCB lecture slides (http://mcb.berkeley.edu/courses/mcb150/Lecture15/Lecture15(6...)

Maybe vendors (e.g. https://www.rndsystems.com/research-area/t-cell-kits) would support a T-cell microsite, with dedicated sections for science journalists, academics and industry scientists. A vendor created this poster on T-cell subsets: https://docs.abcam.com/pdf/immunology/t_cells_the_usual_subs...

This 2018 effort looks useful, https://github.com/hammerlab/t-cell-guide

> We provide practical hints and tips on basic cellular and molecular techniques for handling primary human T cells. We hope that this guide will serve as a reference point to evaluate, discuss, and improve current practices in T cell culturing and manipulation.

Oh wow, there are T cell cartoons :)

https://cellcartoons.net/character/cd8tcell & https://cellcartoons.net/character/cd4tcell

And a manga/anime called Cells at Work! (https://mangarock.to/manga/1684/cells-at-work/first-chapter#...) whose final (June 2021) installment covers Covid-19. There's also a character called Killer T Cell, https://cellsatwork.fandom.com/wiki/Killer_T_Cell_(Squad_Lea...

> Killer T Cell is loud, obnoxious, and quick-tempered, resulting in rivalries with many cells. He also despises it when a non-white blood cell forms a friendship or relationship with one of his kind. As an immature thymocyte he went through training at Thymus school, where apprentice cells like himself learn to become Mature Thymocytes.

Season 1 is streaming: https://www.netflix.com/title/81028791

Possible seeds for a github-pages microsite..

I like the sound of “anticell” which also suggests a function complementary to “antibody”.

It's sounds like a capeshit villain

Don’t remember the study but pretty sure that cross reactivity thesis to common cold eventually didn’t pan out. Believe Derek Lowe wrote about it.

Lowe's Feb 2021 article was about antibodies, not T-cells, https://blogs.sciencemag.org/pipeline/archives/2021/02/10/do...

> Now, you can still make an argument that the T cell component of immunity might provide some protection after a previous coronavirus infection. The current study didn’t address this directly

Lowe's July 2020 article on T-cells, https://blogs.sciencemag.org/pipeline/archives/2020/07/15/ne...

> there are, in fact, people who have both CD4+ and CD8+ T cells that recognize protein antigens from the new coronavirus even though they have never been exposed to SARS, MERS, or the new virus. The paper speculated that this might be due to cross-reactivity with proteins from the “common cold” coronaviruses”, and raised the possibility that there might be a part of the population that has at least some existing protection against the current pandemic.

and

> patients who had caught SARS back in 2003 and recovered ... still have (17 years later!) a robust T-cell response to the original SARS coronavirus’s N protein ..This new work finds that these cross-react with the new SARS CoV-2 N protein as well

There is an open question in the Nature study, about prior, unknown animal coronaviruses which may have previously infected humans and conferred T-cell protection against SARS-CoV-2.

Ah, I stand corrected, thanks! Though not established in the other direction either of course for common cold. But I was wrong to say it was disproven.

https://blogs.sciencemag.org/pipeline/archives/2021/02/10/do...

> But here’s the key part: “cross-react” does not mean “neutralize” and it does not mean “provide protection from”. These antibodies may or may not have been neutralizing against the other coronaviruses, but they don’t seem to have any such effect on the current one. And in keeping with that, having such cross-reactive antibodies seems to provide no protection against catching SARS-Cov2 or against being hospitalized with it if you do. There’s no difference in the infection/hospitalization rates of the people who had cross-reactive coronavirus serum antibodies ready to go versus those who didn’t. They’re basically useless.

Yes, the topic of discussion is T-cells, NOT antibodies.

Yes, but you didn't read the article.

> Now, you can still make an argument that the T cell component of immunity might provide some protection after a previous coronavirus infection. The current study didn’t address this directly, but after these results, it’s at least less likely that that’s happening. The authors make a note of this, and also note that pre-existing mucosal antibodies might exert a protective effect (which this study didn’t examine, either). But prior circulating human coronavirus antibodies, even ones that can bind to the current one – those it looks like we can rule out. Which is too bad.

It's interesting that your comment omitted:

> The current study didn’t address this directly, but after these results, it’s at least less likely that that’s happening.

Why is that?

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