What is Immune Imprinting?

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Why in news?

Two papers, published in the New England Journal of Medicine (NEJM), pointed out those bivalent boosters — made to counter both the Omicron strains and the original Covid-19 strain — don’t generate significantly greater antibody responses than an additional dose of the original mRNA vaccines.

What is immune imprinting?

The phenomenon was first observed in 1947 when scientists noted that in flu patients and termed it an ‘original antigenic sin’
Immune imprinting is a tendency of the body to repeat its immune response based on the first variant it encountered — through infection or vaccination — when it comes across a newer or slightly different variant of the same pathogen.
Imprinting acts as a database for the immune system, helping it put up a better response to repeat infections.
After the body is exposed to a virus for the first time, it produces memory B cells that circulate in the bloodstream and quickly produce antibodies whenever the same strain of the virus infects again.
The problem occurs when a similar, not identical, variant of the virus is encountered by the body.
In such cases, the immune system, rather than generating new B cells, activates memory B cells, which produce cross-reactive antibodies that bind to features found in both the old and new strains.
These cross-reactive antibodies offer some protection but are not as effective as the ones produced by B cells when the body first encountered the original virus.

Q1) What are Lymphocytes?

Lymphocytes are a type of white blood cell. They help your body’s immune system fight cancer and foreign viruses and bacteria. Your lymphocyte count can be taken during a normal blood test at your healthcare provider’s office. Lymphocyte levels vary depending on your age, race, sex, altitude and lifestyle.

Source: Studies find ‘immune imprinting’ might be making bivalent boosters less effective: What is it and how does it work?