This article is an examination of the role genetics appears to play in an individual’s response to infection; it is a follow up to a piece I wrote in January.
Here are the main points:
- For any given individual there are only a limited number of pathogens against which he or she will mount a robust immune response; this is owing the limited number of T cells and Human Leucocyte Antigens (HLA).
- Different individuals mount robust responses against different pathogens, and there are variations associated with both ethnicity and geographical location.
- The wide variation across and within populations benefits the survival of the species.
The contents of this article are based on my understanding of immunology lectures presented by Brianne Barker and virology lectures presented by Vincent Racaniello on YouTube. The links to the first lecture in the series of each are here for Vincent Racaniello and here for Brianne Barker (it’s actually the second lecture; there were technical issues with the first lecture).
The discussion primarily revolves around the cells of the adaptive immune system, namely T and B cells.
T and B cells each have their own receptors on the outside of the cell membrane, called T cell receptors (TCR) and B cell receptors (BCR) respectively. Each cell has a unique receptor configured to match a singular molecular pattern from a pathogen; thus no two T cells and no two B cells have identical receptors in an uninfected person. If a person becomes infected then the relevant T and B cells for the specific pathogen multiply to fight the infection.
Every cell produces proteins – long chains of amino acids – as part of its normal function. Samples of these proteins are broken down into smaller components called peptides – short chains of amino acids. These peptides are presented on the outside of the cell where they can be examined by immune system components. For a healthy cell this results in no action. However, if a virus such as SARS-CoV-2 binds to a cell, its RNA is absorbed into the cytoplasm of the cell where it starts to replicate. The proteins coded for by the SARS-CoV-2 RNA are created as part of the virus multiplication process and samples of these proteins are broken down into peptides and presented on the outside of the cell. The difference in this case is that the peptides are abnormal and thus they trigger a response from whichever immune system cell has a matching receptor pattern.
It is not simply the case that the alien peptide being presented in isolation is all that the T cell requires to become activated. The T cell receptor also has a section that requires a protein structure that it recognises as being from self. This additional structure is the Human Leucocyte Antigens (HLA), of which there are two classes, Class I and Class II, which behave somewhat differently.
Everyone has two versions of chromosome 6, which is the chromosome responsible for HLAs, one from each parent. Thus you have six genes that encode for Class I HLAs and six that encode for Class II HLAs. These genes are equally dominant, thus each cell creates six Class I HLAs and six class II HLAs to present on the cell surface.
If each person has only six HLA Class I genes, how can this protect against every disease? The short answer is that it cannot protect every individual against every pathogen, but it can protect the whole species against every pathogen. This is one reason that different individuals (and different ethnic and geographical groups) have different susceptibility to a specific pathogen.
To summarise, your susceptibility to specific pathogens is, at least in part, determined by your HLA genes, which are inherited equally from your parents. There are geographical differences amongst different ethnicities in the HLA genes they possess – for example, Chinese, Japanese and Koreans are particularly susceptible to influenza. This is likely to explain some of the variation in disease prevalence and severity seen with COVID-19 within and between countries.
John Collis is a recently retired nurse practitioner.
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After two years of watching perfectly healthy people declared as “infected” I honestly don’t believe the medical and scientific community really understand that much about the microbial world.
I’m not saying they don’t know anything, but they don’t know enough to be able to predict practically anything with any real degree of accuracy and are doing a lot of guessing.
Maybe we are in a scientific dark age; the more I think about it the more I tend to think this might be true.
I strongly suspect that there are a few of the best who really do know their stuff, then there are the plodders who are not as clever but are useful in assisting the experts with their research.
But now we have a new category of grifters, diversity hires and activists who are stupid but brazen enough to threaten the first two groups to accommodate their delusions.
I’m sure there are people with a lot of expertise. However, even the most knowledgeable – can they make accurate diagnostics and predictions? It seems to me that they can’t.
It seems to me that the tests are only suggestive of the presence of certain type of pathogen and their ability to predict how it will affect any given person or group of people is very poor to non-existent.
A certain type opf historia, the political class and its PR department the MSM all decided they knew all there was to know and life would be better because they willed it. Many scientists have done the same; some just fell into the trap of overestimating their knowledge while other saw such claims as a way to power and influence (perhaps money too).
In a sense we will always be in a scientific dark age because we will never know what we don’t know. There will always be more to discover. All the more depressing, therefore, to see science as a political play thing, just as the security services became under a certain PM.
I’m not an expert in this topic but I have read the brilliant How the Immune System Works by Lauren Sompayrac.
In the lecture on the Magic of Antigen Presentation there is a discussion on the polymorphic (many different forms) nature of class I MHC* molecules, and how that ties in with there being 6 genes for class I MHC proteins in humans. Lauren says ‘the possibility of ‘owning’ up to six different class I MHC molecules increases the probability that each of us individually would have at least one class I MHC molecule into which a given pathogen’s protein fragment will fit.
Lauren does say the polymorphic nature of MHC prevents the situation where ‘a virus might happen to wipe out the entire human population, because no killer T cells could be activated to destroy the virus-infected cells, So polymorphic MHC molecules give at least some people in the population a chance of surviving an attack by a clever pathogen
So my layperson’s reading of that (and i must emphasise it’s a layperson’s reading) is that individually because the combined effect of the 6 genes and polymorphic nature of class I MHCs there is a good chance any individual will recognise a dangerous pathogen.
But it’s clear also that genetics will play a part in any individual’s ability to fight off a pathogen. So the points in the article are well made and seem to be consistent with that book.
In any such discussion of genetics it’s always good to point out the importance of epigenetics as well as genetics. Epigenetics is the study of how your behaviours and environment can cause changes that affect the way your genes work. I think I read that roughly and more generally two thirds is about epigenetics and one third genetics. So it’s important in life that we concentrate on behaviours that improve the epigenetic position (well unless you want to live a rock and roll lifestyle which is fair enough) rather than be be resigned to saying we have bad genes.
(* to quote from John’s earlier article to explain connection between HLA and MHC: They have a generic name – Major Histocompatibilty Complex – but are given a specific name in human beings, Human Leucocyte Antigens (HLA)
It’s interesting to read a bit more about inherited capability with regard to certain types of infection. However, as you mention T cells, it would be worth noting that their purpose seems to be to provide ‘long term memory’ of earlier attacks.
A while back – late 2021, there was a fair bit of commentary on this topic on this site, which led me to use the services of an organisation that performed T cell assessment re. SARS-Cov-2. My decision to do that was that I did have an infection near the start of the panic in 2019/20, and it would have been interesting to see if it really was caused that way. As it turned out, it probably wasn’t caused by that, so most likely just a typical “common” one.
The firm I used was Oxford Diagnostic Laboratories, in Abingdon, Oxon.
This https://www.cebm.net/covid-19/what-is-the-role-of-t-cells-in-covid-19-infection-why-immunity-is-about-more-than-antibodies/ might be of interest as well.
I’m researching possible “early spread.” When you had your infection in 2019/2020 did you happen to go to the doctor and, if so, did you receive a test for influenza? What were the results if you did?
Have you tested positive for Covid or been sick since then?
One of the studies cited in your paper (Footnote # 21) provides this info:
“Potential for long-term immunity
Early research suggests that the antibodies in people infected with SARS-CoV-2 dropped significantly within 2 to 3 months [21,22],
…. SARS-CoV-2-specific memory T cells have also been detected in exposed seronegative healthy individuals (relatives of confirmed cases), which may indicate asymptomatic infection. One study has shown that ~93% of “exposed asymptomatic” individuals had a T cell response to SARS-CoV-2, despite seropositivity in only 60% of cases [28].
To me, this suggests that 40 percent of people who tested “negative” for antibodies proper (IgG, IgM and/or IgA) DID have memory T cells at a later date (showing immunity and thus possible “proof” of prior infection). This suggests they had the virus but the traditional antibody tests didn’t provide evidence of this (at least in 40 percent of those who received these tests).
I happen to believe this statement is probably true (also from same study):
“Asymptomatic infections may therefore be more common, and antibody testing alone may underestimate the true prevalence of the infection or population immunity.”
I wonder if something sinister might be going on RIGHT NOW ….
The Drudge Report has a factoid every day that compares Covid “cases” as of today’s date to the same date one year ago. Here’s today’s info:
“Covid cases in USA, 7-day average”
6-12-22: 109,517
6-12-21: 14,480
Comments: This is a 7.56X increase from one year ago. This is happening when far more people have been vaccinated today than were vaccinated 12 months ago. This spike is happening in the summer, not the “cold and flu” months where previous big spikes have occurred.
Also: I can share some family anecdotes that seem to confirm what I am reading in some alternative media sites, namely that health officials (and doctors’ offices) are DISCOURAGING people to get Covid tests.
Three examples from my family: My vaccinated wife went to the doctor last Thursday complaining of chest pains and generally feeling run-down and not herself. She was told she probably had bronchitis. But, although she asked, this medical clinic did NOT give her a Covid test. While she was in a patient room waiting to see a doctor, she overheard a patient in the next room, literally pleading to receive a Covid test. The doctor told her she did not need such a test and did not give her one despite her repeated requests to the get this test. Today, I hear that my father-in-law (also vaxxed and boosted) has gone to the hospital with various symptoms (he’s feeling and looking awful) and was told he did not need a Covid test. (I also am alarmed that his symptoms might be a flare up from a past major medical issue he suffered years ago).
It is clear to me that the Powers that Be have disseminated “guidance” throughout the healthcare networks to NOT administer Covid tests if at all possible.
Take-away: We don’t know how many people would be “testing positive” if tests were being administered like they were for the last 24 months of the pandemic. In other words, that 7.6-fold increase in cases would probably be a 15-fold increase if everyone that wanted a test was getting a test. There is clearly a massive and under-counted spike in cases that is being covered up.
I also can report two close friends, both elderly, who have spent the past week in rough condition after testing positive for Covid. However, they tested positive by a store-bought “at-home” or “rapid” test their son brought them. These cases were NOT “mild” or “asymptomatic” either. My friends were very sick and still aren’t anywhere close to 100-percent. These friends have received two jabs plus two boosters. FWIW, they have also experienced strange “adverse events” (including a stroke (!), possible recurrence of a cancer and obvious increase in “brain fog” in one of my friends) … which, alas, they do not associate with their jabs.
I also note that my wife told me her nurse and doctor did NOT ask her about her jab status, which suggests to me that health officials don’t want to have any records that might show a correlation in new medical conditions and the vaccine.
Summarizing: As more people have been vaccinated and jabbed, we are getting far MORE cases, more “re-infections” and MORE odd and concerning medical conditions. During all of this, health officials seem to be intentionally forgoing the tests they were encouraging everyone to get for two years. Nor do these health practitioners seem interested in one’s vaccine status.
… And then you have reports like Justin Bieber’s and “SADS” (Sudden Adult Death Syndrome) now being a real thing … and Ed Dowd tells us disability claims have gone up 3 million since the vaccines were rolled out … and one is more discombobulated than ever that all of this “news” is off limits to our mainstream “watchdog” press.
Our genes determine everything about us, so no surprises here.