STUDY: Mild/Asymptomatic COVID-19 NOT providing lasting T-CELL BASED IMMUNITY

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  • Wed, Sep 09, 2020 - 07:41pm

    #1
    Joe_V

    Joe_V

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    STUDY: Mild/Asymptomatic COVID-19 NOT providing lasting T-CELL BASED IMMUNITY

COVID-19 Immunity Short-Lived For Those Who Are Asymptomatic Or Had Mild Symptoms:

https://www.medrxiv.org/content/10.1101/2020.09.05.20187435v1.full.pdf

Summary
46 The adaptive immunity that protects patients from coronavirus disease 2019 (COVID-19),
47 caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is not well
48 characterized. In particular, the asymptomatic patients have been found to induce weak and
49 transient SARS-CoV-2 antibody responses, but the underlying mechanisms remain unknown;
50 meanwhile, the protective immunity that guide the recovery of these asymptomatic patients is
51 also not well studied. Here, we characterized SARS-CoV-2-specific B-cell and T-cell responses
52 in 10 asymptomatic patients and 49 patients with other disease severity (mild, n=10, moderate,
53 n=32, severe, n=7) and found that asymptomatic or mild symptomatic patients failed to mount
54 virus-specific germinal center (GC) B cell responses that result in robust and long-term humoral
55 immunity, assessed by GC response indicators including follicular helper T (TFH) cell and
56 memory B cell responses as well as serum CXCL13 levels. Alternatively, these patients
mounted potent virus-specific TH1 and CD8+ 57 T cell responses. In sharp contrast, patients of
58 moderate or severe disease induced vigorous virus-specific GC B cell responses and associated
TFH responses; however, the virus-specific TH1 and CD8+ 59 T cells were minimally induced in
60 these patients. These results therefore uncovered the protective immunity in COVID-19 patients
61 and revealed the strikingly dichotomous and incomplete adaptive immunity in COVID-19
62 patients with different disease severity, providing important insights into rational design of
63 COVID-19 vaccines.

  • Wed, Sep 09, 2020 - 10:08pm

    #2

    davefairtex

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    are you sure you read this study?

I ask this, because the study doesn’t say what you think it says.

What it says is:

If you are asymptomatic, you end up developing T-cell immunity.

If you have moderate to severe disease, you end up developing B-cell immunity.

What’s more, asymptomatics don’t generate B-cell immunity, and moderate to severe patients don’t generate T-cell immunity.

What’s more, it appears that the T-cell immunity is what keeps you asymptomatic.  That’s certainly the outcome I’d like to have.

These data therefore revealed that albeit the failure in mounting SARS-CoV-2-specific humoral immunity, asymptomatic or mild symptomatic patients were able to induce a profound virus-specific cellular (TH1 and CD8+T cell) immunity

It doesn’t make any claim as to how long lasting any immunity happens to be.

The paper does also hint that T-cell immunity from the common cold might offer protection from SC2.

My interpretation:  it appears that T-cell immunity keeps you asymptomatic, while the B-cell immunity is the body’s backup plan – if you don’t generate those T-cells that keep you asymptomatic.

I encourage you to read the “Discussion” section, starting on line 274:

In contrast to humoral immunity, we found that the virus-specific TH1 and CD8+T cell immune responses were rapidly induced and sustained in asymptomatic or mild  symptomatic patients as compared to patients with moderate or severe disease, which presumably protect them from progressing to severe COVID-19. We also envision that the rapid and robust virus-specific TH1and CD8+T cell responses may effectively curtail the SARS-CoV-2 replication, which results in the inefficient viral antigen production and limits the GC reaction that requires sufficient antigen stimulation.

  • Sun, Sep 13, 2020 - 03:48pm

    #3
    cgarcia

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    STUDY: Mild/Asymptomatic COVID-19 NOT providing lasting T-CELL BASED IMMUNITY

I agree that antibodies are overated. And it’s quite possible that T or B cells might not provide adequate immunity.

But then why reinfections are so rare?

Maybe the immunity that matters for SARS-CoV-2 lies INSIDE the cells (intracellular immunity), and not in the bloodstream? Only time (and research) will tell.

  • Thu, Sep 17, 2020 - 12:42pm

    #4
    tg43

    tg43

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    STUDY: Mild/Asymptomatic COVID-19 **is** providing lasting T-CELL BASED IMMUNITY

How do I tag @Davefairtex in this ?

I caught this article/post just before I had a few days away, and I’ve got a ‘feeling’ about it – like it might be on to something.  Leaving aside the sense that the authors hoped it would bring the work nearer to a vaccine, and the very real possibility it has been translated from another tongue.  This has implications if correct.

If you are asymptomatic, you end up developing T-cell immunity.

T cell immunity was mentioned in one of the videos, in that people still had T cells 13 years later that remembered SARS Classic.  ie, this lasts *years*  so would certainly prevent you getting sick with it again in a single year timeframe.  However, this works best with a low inoculum – so your T cells get the head start they need.

If you have moderate to severe disease, you end up developing B-cell immunity.

B cell immunity was what waned after 3 months with SARS2, and presumably that is why we see reinfections.  I’m thinking back to common cold anecdotes too: there’s always someone who “can’t shake it’, or who “gets one cold after another” in the season.

The implications -for us in the UK at least – are for the coming winter.  Thinking of all the people who ended up in UK hospitals in April/May with severe cases and waning B-cell immunity – are these going to be up for catching the virus again as the virus spreads through the nation this autumn?  The second wave will (could) be the first wave all over again- comprising the first lot who didn’t get lasting immunity and ended up in hospital first time round, plus new cases that missed getting it first time round or got bored with the restrictions and caught it in time for Christmas.

So just an idea, putting it out there, what do you think ?

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