Author Topic: T-Cell Immunity  (Read 1418 times)

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T-Cell Immunity
« on: June 25, 2020, 11:16:57 AM »
It has been my understanding thus far that detectable B cell antibodies develop in 99% of Covid carriers, regardless of symptoms. They make take 14 days from onset, they may disappear, and the assays attempting to detect them may be imperfect, but at some point they are always there.

It is still hypothetically possible a portion of the population is genetically less susceptible (immune), similar to how Children are less susceptible, and suggested by the tightly confined spaces like cruise and military ships were typically 40% of the population did not have detectable PCR Positive nose swabs, irregular CT lung scans, or B-Cell antibodies. However, it also possible the exposure was not uniform across the ships, especially if we assume only a handful of super spreaders are responsible for directly infecting the other passengers, and most Covid carriers are not contagious most of the time.

However, claims have been emerging about T-Cell immunity resulting from Covid infections without any present B-Cell antibodies. This T cell reaction can be detected by simulating a Covid infection in the blood sample, in a complicated assay described here -  https://bio-protocol.org/e2302.


Can anybody shed more light on this topic?




Exhibit A is a NY study of 1343 symptomatic PCR-Positive Covid carriers, all but 3 of whom developed B cell antibodies

https://www.medrxiv.org/content/10.1101/2020.04.30.20085613v1



Exhibit B is a tiny French study that examined 9 Covid patients, 8 household contacts, and a few old blood samples for control. The samples were drawn 47 days after infection, so it's possible antibodies simply weren't there anymore. 6 out of 8 of the studies contacts had some symptoms, but none tested positive on PCR swab tests. We know those tests are only 70% accurate, so it doesn't tell us much.

They found 6 out of 8 contacts all had a unique T cell response that was not present in any of the control samples that were not exposed to Covid. Although it was still different than the T cell response seen in the 9 confirmed patients.

The study appears to contradict itself, at one point stating 6/8 contacts exhibited symptoms (4 fever, 3 cough) [Page 6, line 130], but then stating 5/6 contacts with T cell responses were asymptomatic [Page 8, line 168]

https://www.medrxiv.org/content/10.1101/2020.06.21.20132449v1

I will continue posting more information as I research it.
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Re: T-Cell Immunity
« Reply #1 on: June 25, 2020, 11:39:02 AM »
Additionally from here it certainly seems like the vast majority of people who’ve tested positive for COVID developed antibodies.
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Re: T-Cell Immunity
« Reply #2 on: June 26, 2020, 05:14:45 AM »
Here is another study showing 285 out of 285 symptomatic Covid carriers developed antibodies.
https://pubmed.ncbi.nlm.nih.gov/32350462/

I'm starting to think the studies only researched symptomatic carriers, and there is no evidence all asymptomatic carriers develop detectable IGg B cell antibodies.

That would suggest more than 20M people in the US were infected, the mortality rate is lower than 0.5%, and the West is far closer to herd immunity than previously understood.
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Re: T-Cell Immunity
« Reply #3 on: June 26, 2020, 06:29:53 AM »
A Taiwanese study shows 3/8 asymptomatic carriers did not have Igg B cell antibodies as late as 42 days after infection.

 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7177139/
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Re: T-Cell Immunity
« Reply #4 on: June 26, 2020, 09:23:10 AM »
You're suggesting that the 20 million number is just B cell immunity and the T cell immunity may be much higher than that?
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Re: T-Cell Immunity
« Reply #5 on: June 26, 2020, 11:04:35 AM »
Someone made this comment on one of Dan's commentaries:
Corona viruses are mostly dependent on cellular immunity not humoral immunity.

What does this mean?  I had understood that humoral and cellular immunity are both required, both work together.

I haven't had time to read the articles you posted, but just wondering if any of them talk about this.  When they say that antibodies do or don't exist, do they mention anything about B memory cells existing?  I had thought that it's natural for antibody levels to increase after infection then gradually decrease.  The absence of antibodies 2-3 months or years after infection should not be indicative of decreased immunity, as long as B memory cells are present to produce those antibodies whenever needed.  Did you read anything like this in those articles?

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Re: T-Cell Immunity
« Reply #6 on: June 26, 2020, 12:29:36 PM »
You're suggesting that the 20 million number is just B cell immunity and the T cell immunity may be much higher than that?
Yes. Based on extensive seroprevalence studies we know the mortality rate of antibodies positive carriers is 0.5-1%, so 120k dead is 12-24m seropositive. However, it appears there’s a whole new class of T Cell immune individuals that hasn’t been researched yet
Someone made this comment on one of Dan's commentaries:
Corona viruses are mostly dependent on cellular immunity not humoral immunity.

What does this mean?  I had understood that humoral and cellular immunity are both required, both work together.

I haven't had time to read the articles you posted, but just wondering if any of them talk about this.  When they say that antibodies do or don't exist, do they mention anything about B memory cells existing?  I had thought that it's natural for antibody levels to increase after infection then gradually decrease.  The absence of antibodies 2-3 months or years after infection should not be indicative of decreased immunity, as long as B memory cells are present to produce those antibodies whenever needed.  Did you read anything like this in those articles?

I don’t understand the full nuance, but the studies do show asymptomatic people who have been infected and do not have any Igg antibodies, while 100% of symptomatic patients do have them

If only our President had a bit higher IQ, he’d be trumpeting this already...
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Re: T-Cell Immunity
« Reply #7 on: June 26, 2020, 04:02:01 PM »
I'm still a bit lost, and I think it's because I'm not sure what the big question is.  Are you bringing all these references to figure out:

1. Do antibody tests really tell us who's been infected?
2. How long does immunity last?
3. How many people have been infected, and therefore how close might we be to herd immunity?
4. Something else?

I had assumed you were interested in 2, but now I think it might be 3.

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Re: T-Cell Immunity
« Reply #8 on: June 26, 2020, 04:56:16 PM »
I'm still a bit lost, and I think it's because I'm not sure what the big question is.  Are you bringing all these references to figure out:

1. Do antibody tests really tell us who's been infected?
2. How long does immunity last?
3. How many people have been infected, and therefore how close might we be to herd immunity?
4. Something else?

I had assumed you were interested in 2, but now I think it might be 3.
I am curious about 3.

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Re: T-Cell Immunity
« Reply #9 on: June 26, 2020, 05:28:13 PM »
I'm still a bit lost, and I think it's because I'm not sure what the big question is.  Are you bringing all these references to figure out:

1. Do antibody tests really tell us who's been infected?
2. How long does immunity last?
3. How many people have been infected, and therefore how close might we be to herd immunity?
4. Something else?

I had assumed you were interested in 2, but now I think it might be 3.

I think #2 is the most important question. It has the ability to render the answers to the other questions moot.
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Re: T-Cell Immunity
« Reply #10 on: June 27, 2020, 04:08:39 PM »
I'm still a bit lost, and I think it's because I'm not sure what the big question is.  Are you bringing all these references to figure out:

1. Do antibody tests really tell us who's been infected?
2. How long does immunity last?
3. How many people have been infected, and therefore how close might we be to herd immunity?
4. Something else?

I had assumed you were interested in 2, but now I think it might be 3.
Thanks. 1 & 3.

I don't think any of this data is relevant to #2 as we have no idea if and how long various antibodies provide immunity, but it would build a herd immunity hypothesis
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Re: T-Cell Immunity
« Reply #11 on: June 28, 2020, 07:05:24 PM »
?s=21

Don’t know how that’s consistent with the Diamond Princess & other ships
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Re: T-Cell Immunity
« Reply #12 on: June 28, 2020, 07:15:30 PM »
Somewhat related (and disappointing point of view from my perspective):

https://turbidplaque.com/grav/blog/2020-immunity-passports
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Re: T-Cell Immunity
« Reply #13 on: July 05, 2020, 01:45:18 PM »

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Re: T-Cell Immunity
« Reply #14 on: July 05, 2020, 01:56:25 PM »
https://www.bbc.com/news/health-53248660
Most interesting part is how someone can be protected personally but not contribute to herd immunity (as they can still transmit virus despite not being “infectable”)
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