Recent studies are starting to say that the neutralizing antibodies elicited by prior COVID-19 infections and vaccinations are ineffective against the omicron variant. I talked about them at Study shows absence of omicron neutralization with the Pfizer and AstraZeneca shots, and Omicron can evade antibodies from vaccinated and COVID convalescent people.
But, there is more to vaccine-induced and natural immunity than antibodies. Germs also stimulate T-cells to form an immune response stored in their memory.
What are T-cells?
The blood has white blood cells (WBC) that fight infections. There are several kinds of WBCs like neutrophils, monocytes, and lymphocytes. There are many types of lymphocytes like the CD8+ T-cells.
In a recent study about immunity against the omicron variant, the cytotoxic CD8+ T-cells are in focus. For the remainder of the article, I will refer to the cytotoxic CD8+ T-cells as cytotoxic T-cells for easier reading.
Cytotoxic T-cells circulate the body looking for infected cells. A cell can become infected if a virus gets inside it or immune cells like macrophages ingest them.
The virus has protein sequences that are foreign or “non-self” to the body. These “non-self” sequences are brought to the surface of the macrophages and become recognizable to the cytotoxic cells as epitopes. Epitopes or antigenic determinants are the part of an antigen that is recognized by the immune system, specifically by antibodies, B cells, or T cells.
Antigens are substances foreign to the body that can elicit an immune response. For this article, the immune response will come from the cytotoxic T-cell. put this earlier on.
The image below on the right shows an immature cytotoxic CD8+ T-cell that encountered a cell that has viruses inside it. Imagine those cells as infected with the SARS-CoV-2 virus for the first time. The cytotoxic T cell attaches to the antigen on the infected cell’s surface using a T-cell receptor (TCR).
The T-cells then destroy the infected cells and come out mature with a “memory” of the SARS-CoV-2. That “memory” is essential so that if it reencounters the SARS-CoV-2, the cytotoxic T-cells can destroy them faster before the viruses cause severe COVID-19 infection.
The memory development in the cytotoxic T-cells also happens in immunization.
Omicron Mutations
But, there can be a problem if the viruses mutate. Mutations are changes in the amino acid sequences. These mutations can render a new variant very different from the original virus and make them unrecognizable, particularly the antibodies and cytotoxic T-cells. Once that happens, severe disease or death can occur.
The omicron variant has fifty mutations, and most of the mutations are in the spike protein. The COVID virus uses the spike protein to attach to human cells.
The question arises, Will cytotoxic T-cells from a previous COVID-19 infection protect the omicron?
Cytotoxic t-cells are still effective
That is the purpose of the study from the National Institute of Allergy and Infectious Diseases, Johns Hopkins University, and Immunoscape.
The investigators took T-cells from thirty people who had COVID-19 in April and May 2020 before the omicron variant came out.
Their analysis examined if the previously identified viral epitopes or protein sequences stored in the memory of the cytotoxic T-cells from these individuals who recovered from COVID-19 are still present in the newly described Omicron.
Their findings showed that the many mutations in the omicron variant did not affect the effectiveness of the cytotoxic T-cells from previous COVID-19 infections. The results mean that the cytotoxic T-cells of people recovered from COVID are still effective against the omicron variant and can prevent severe COVID-19.
The results also suggest that cytotoxic T-cells developed from the COVID jabs are effective too against omicron.
Low omicron death rate
The latest total of omicron variant cases around the world today is 4,295. I calculated that by downloading the data from GISAID, GISAID is a repository of the newest genome sequences.
Among 4,295 omicron cases, there has only been one reported death in the UK. That omicron death is controversial due to lack of transparency. The Daily Mail asks, Did Britain’s ‘first Omicron death’ die FROM the Covid variant or WITH it? Professor slams government’s “lack of transparency” and says No. 10 (No. 10 Downing St. is the Prime Minister’s residence) is causing ‘unnecessary alarm’ – adding: ‘The patient could have been hit by a bus.’
The percentage of death, 1/4,295 cases or 0.02, can provide clinical support that the cytotoxic CD8+ T-cells continue to protect against the omicron variant.
The research, Minimal cross-over between mutations associated with Omicron variant of SARS-CoV-2 and CD8+ T cell epitopes identified in COVID-19 convalescent individuals, is a preprint available at medRxiv.
In summary, cytotoxic CD8+ T-cells from the vaccinated and people who recovered from COVID-19 are still effective against the omicron variant.
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Articles about the immune response to COVID-19
- Computer model: Natural antibodies still effective on the omicron variant
- Ten Studies showing a low risk of COVID-19 reinfection among unvaccinated
- High Anti-SARS-CoV-2 Antibodies Among the Unvaccinated in Bangui, Central African Republic
- Protective Antibodies against SARS-CoV-2 are the same in Convalescent and Vaccinated
- Asymptomatic or mild symptomatic COVID-19 elicits effective and long-lasting antibody responses in children and adolescents
- Can coronaviruses elicit long-lasting immunity?
- 60% may already have Immunity to COVID-19
- Pre-Existing T-Cells Stop COVID-19 Before it Starts
- Harvard: Immunity from mild COVID-19 infection much better than vaccination
- Natural Immunity Protected Tanzania and Zambia from COVID-19
- CD4+ Cross-Reactivity between Seasonal Coronavirus Colds and COVID-19
- Antibodies to COVID-19 can Exist in the Uninfected
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