IMMUNE IMPRINTING

1. Context

2. Immune imprinting

3. Findings so far

• It was in 1947 when the concept of immune imprinting came to light for the first time.
• Scientists observed that the bodies of individuals who were infected with the flu previously and were vaccinated against the present circulating strain produced antibodies against the very first strain they had come into contact with. This had been found in a report brought forward in the journal Nature.
• In those times, it was called "original antigen sin". Today, however, the concept is termed imprinting. In the years ahead, scientists have concluded that this imprinting plays a role of a database for the immune system of the body. This database helps the body lead to a better response to repeat infections.

4. Mechanism

• Once the body has come in contact with a virus for the very first time, the body gives rise to memory B cells. These cells circulate in the bloodstream.
• These then speedily produce antibodies just when the body is exposed to the same strain of virus again.
• Once the body has come in contact with a virus for the very first time, the body gives rise to memory B cells.
• These cells circulate in the bloodstream. These then speedily produce antibodies just when the body is exposed to the same strain of virus again.

5. Findings of the recent study pertaining Corona virus vaccine

• In the first study, done by the researchers of the Columbia University Vagelos College of Physicians and Surgeons in New York, participants were 40 individuals, who had already received three shots of the original or monovalent vaccine.
• To experiment, 19 of them were given a booster (fourth shot) of the original vaccine while 21 received a booster of the new bivalent vaccine.
• It was observed that the bivalent boosters "did not elicit a discernibly superior virus-neutralizing peak antibody response as compared with boosting with the original monovalent vaccines" across all coronavirus strains tested.
• In the second study, researchers of the Beth Israel Deaconess Medical Center in Boston evaluated immune responses in 15 participants, who had received the original monovalent boosters, and in 18 participants, who had received the bivalent boosters.
• It was found that "median BA.5 (Omicron) neutralizing antibody titer was similar after monovalent and bivalent mRNA boosting, with a modest trend favoring the bivalent booster by a factor of 1.3."
• The findings of both studies suggested immune imprinting might be posing a hurdle in the success of the bivalent or variant-specific vaccines.

6. How to circumvent immune imprinting

• Currently, several ongoing studies are trying to find a way to deal with imprinting. Some scientists have said nasal vaccines might be better at preventing infections than injected ones. They believe the mucous membranes would create stronger protection, despite carrying some imprint of past exposure.
• Researchers are also trying to find if spacing out coronavirus vaccine shots on an annual basis, could help with the problem of imprinting.

For Prelims