Since the Omicron variant has rapidly increased Covid infections, the focus is once again on antibodies, and rightly so.
Antibodies play a fundamental role in fighting viruses and are important in preventing the coronavirus from infecting our cells.
This is the reason why some countries have set up booster vaccination campaigns in response to recent covid surges, in order to increase antibody levels.
But there’s a problem. Covid antibodies do not persist as well, hence the need for boosters.
In fact, while these additional injections maintain a good protection against severe Covid, it is estimated that people who receive a third dose of the Pfizer vaccine will see their protection against the development of Covid symptoms (of any degree) drop from the 75% to the 45% during the 10 weeks following your booster.
Scientists have questioned whether permanently recharging the antibodies, only to see them diminish soon, is a sustainable strategy.
If we want to develop a lasting immunity to covid, maybe it’s time to take another look at our broader immune response.
Antibodies are just a part of our intricate and intertwined immune system. Specifically, maybe it’s time we focused on T cells.
How Different Immune Cells Work
When the body is infected, say with a virus, it responds by producing white blood cells called lymphocytes. The main types of lymphocytes are B cells, which produce antibodies, and T cells, which support B cell antibody production or they act as killer cells to destroy the virus.
Some T cells and B cells also become long-term memory cells that know what to do if they encounter the same infection again.
B cells and T cells “see” the virus in different ways.
In general terms, B cells they recognize shapes on the outside of the virus, creating antibodies that latch onto or dock with them (a bit like 2 matching puzzle pieces).
![Ilustración de anticuerpos (en blanco) uniéndose a las proteínas Spike del virus que causa covid.](https://i0.wp.com/c.files.bbci.co.uk/11C6A/production/_122701827_tcell11.jpg?resize=640%2C360&ssl=1)
Instead, T cells recognize fragments of the amino acids that make up the virus, including fragments that are normally found inside.
Each virus has many unique characteristics, both inside and out. A person’s immune response can end up producing a variety of T cells and B cells that, between them, attack a wide range of those traits.
This is sometimes called “response amplitude“. A good amplitude response involves many different lymphocytes seeing different parts of the virus, making it very difficult for the virus to completely hide itself.
Ómicron worried many researchers because a key part of its external structure that antibodies target, the spike protein or s pike (in red in the first image above), has many mutations, which reduces the ability of antibodies to bind to the virus and neutralize it.
However, because the T cells focus on other parts of the virus, such mutations may not prevent it from being identified.
In fact, preliminary data, still pending peer review, suggest that this is the case.
E This is reassuring, because the spike protein of the virus has changed a lot during the pandemic, suggesting that it might always be mutating out of reach of antibodies.
However, T cells should be less susceptible to viral mutation. T cells designed to fight covid also seem to last much longer in the human body than antibodies.
But do T cells have a important effect?
We already know a lot about the critical role of T cells in other viral infections.
This knowledge suggests that, against Covid, a good T cell response is not only necessary to help B cells produce antibodies, but should also create killer T cells that can broadly recognize the coronavirus , protecting against multiple variants.
Evidence on Covid and T cells is still being collected. However, it is gradually becoming clearer that T cells appear to play an important role in this disease .
![Una mujer es vacunada contra la covid](https://i0.wp.com/c.files.bbci.co.uk/1437A/production/_122701828_tcell12.jpg?resize=640%2C360&ssl=1)