Why antibodies are not the only defense against omigran

Released Friday, December 17, 2021 at 6:51 p.m.

Since the beginning of the fight against Govt-19, an important component of the immune system has come to the fore: antibodies.

These Y-shaped proteins have recently made headlines again because the antibodies produced by the vaccine do not work against earlier versions of the virus against the Omigron variant – at least not without a booster dose.

To fight the virus, antibodies attach themselves to the tip of its spike protein, which prevents it from being used to enter cells, making a person sick.

But they are not the only ones fighting. In fact, it is “a complex and integrated response, very beautiful from an evolutionary point of view,” says Roger Shapiro, a Harvard immunologist.

– “Carpet of Bombs” –

Within minutes and hours following the virus’s infiltration, the proteins sound the alarm to recruit large arms called the “innate” immune system.

The first to kick are neutrophils, which make up 50 to 70% of white blood cells, and they quickly go to war and die.

Other white blood cells, macrophages, swallow germs and discard small parts of them, dragging other sharp colleagues: threateningly natural killer cells and dendritic cells, which are responsible for gathering information.

John Verry, an immunologist at the University of Pennsylvania, compared the situation, saying “it’s like deploying that area with bombs, hoping to do as much damage as possible to the invader.” “Invite headquarters to prepare special units at the same time.”

– B and D lymphocytes: spies and killers –

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If the attacker is not repelled, the adaptive immune system starts.

A few days after infection, B cells detect the threat and begin to produce antibodies.

The vaccine allows B lymphocytes to train superficially – especially within the armpit lymph nodes, near the bite site – to be ready.

Roger Shapiro compares them to intelligence agents, with important information about the enemy.

Strong antibodies called “neutralizers” are like chewing gum placed at the end of a key: they prevent the virus from opening the door to our cells.

Other types of antibodies do not attach, but still help by redirecting the virus to cells of the immune system or calling for help to intensify the response.

The major partners of B lymphocytes, D lymphocytes, can be divided into two broad categories: cytotoxic “helpers” and “killers”.

The latter are “like killers, they attack infected cells,” Roger Shapiro explains. But these killers also cause co-damage.

Paramilitaries play the role of “generals”, pursuing expertise, mobilizing troops and directing them towards the enemy, while promoting the production of B lymphocytes antibodies.

– To prevent serious incidents –

Due to the high number of mutations in the spike protein in Omigran, this variant can very easily escape from the neutralizing antibodies created by the vaccine or past infection.

The bad news is, it does increase your chances of getting sick. The good news is, D cells are hard to cheat.

These, within the infected cells, can identify different components of the virus during its replication, John Verry details.

The disguise worn by the virus allows them to go unnoticed by the antibodies, but they are very good at recognizing the enemy.

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“Killer” T cells carry out commando tasks, dig a hole in the cells and explode them, triggering reactions that allow the addition of inflammatory proteins called cytokines to fight.

Depending on the speed of the immune response, a vaccinated person may develop mild symptoms such as colds or mild symptoms such as the flu if they are still sick. But the risk of developing a severe case of the disease is drastically reduced.

This does not prevent a booster dose from being effective: it boosts the production of all types of antibodies and further absorbs B and T cells.

“Omigron is worrying, but the glass is still half full,” said John Verry. “He’s not going to escape our immunity completely.”

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