Immune Imprinting

Immune Imprinting

Subject : Science & Tech

Section: Biotechnology

Context:

• Studies find ‘immune imprinting’ might be making bivalent boosters less effective.

What is immune imprinting?

• 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.
• Background:
  • The phenomenon was first observed in 1947, when scientists noted that “people who had previously had flu and were then vaccinated against the current circulating strain, produced antibodies against the first strain they had encountered.
  • At the time, it was termed the ‘original antigenic sin’ but today, it’s commonly known as
• Over the years, scientists have realised that imprinting acts as a database for the immune system, helping it put up a better response to repeat infections.
• After our 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.

Problems in immune imprinting:

• When a similar, not identical, variant of virus is encountered by the body, the immune system rather than generating new B cells, activates memory B cells which in turn produce antibodies that bind to features found in both the old and new strains, known as cross-reactive antibodies.
• These cross-reactive antibodies do offer some protection against the new strain, they aren’t as effective as the ones produced by the B cells when the body first came across the original virus.

How to circumvent immune imprinting?

• Currently, there is no proven way of circumventing it, though scientists believe nasal vaccines can escape from immune imprinting.