In everyone’s immune story, the first influenza virus infection is paramount, as it shapes how we respond to future aerial influenza viruses, including emerging epidemics such as SARS-COV-2.

It has been published in the journal PLOS, says virologists at the University of Pittsburgh (United States) Medical School in the United States of America. According to him, the first influenza infection may explain the different levels of severity and susceptibility to Kovid-19.

“Once you have the flu, you are not immune to all future flu viruses, Seema Lakdawala, assistant professor of microbiology and molecular genetics and lead author of the study, explains. Just because you had SARS virus in 2003 or one of the common cold coronaviruses does not necessarily mean that you cannot get infected with SARS-Cove-2. But your susceptibility to infection may be different from someone who has not suffered coronovirus. “

In search of antigenic original sin

To analyze the immune response to the flu, researchers used ferrets, which have similar susceptibility to humans. The experiment was designed to test the concept of “antigenic original sin”, that is, the moment when a person’s first exposure to the pathogen marks their immunity to all future infections.

This phenomenon has already been observed in previous influenza epidemics and epidemic-affected populations. For example, the 2009 H1N1 influenza pandemic disproportionately affected people between the ages of 5 and 24, suggesting that older people were exposed to a previous strain of influenza that gave them permanent immunity, thus Protected from new stress.

In the ferret experiment, scientists infected individual groups of ferrets who did not have one of the flu from two different strains of the flu – the H3N2 seasonal flu or the 2009 H1N1 pandemic flu – and waited. Three months to develop the immune system. A more mature immunity against the stress to which they are exposed.

Fermented immunity against the H3N2 strain was then exposed as infectious with the H1N1 virus, and immune fermentation against the H1N1 strain was exposed as infectious with the H3N2 virus.

Researchers mixed infectious flaws with their peers for 8 hours for a 5-day period to mimic human working days or for 2 consecutive days on their family weekends.

An adaptive immune response

The results showed that ferrets already infected with the H1N1 virus were protected against transmission of H3N2 influenza via air from another infectious ferret. But ferrets already infected with the H3N2 virus did not have the same level of protection against the H1N1 flu and were infected as an animal without any prior immunity.

“It was really amazing”Pro. Woodcutter “Our immunity may determine our susceptibility to subsequent infections, but it is not uniform”.

While this experiment did not reveal whether ferrets infected with the H1N1 virus were provided protection against H3N2, or why previous infection with H3N2 did not block the H1N1 virus, scientists found that antibodies that neutralize antibodies Was not due to antibodies. These antibodies are acquired after vaccination or infection that specifically target and neutralize a defined pathogen. This finding indicates that immunity was possibly due to an adaptive immune response: this means that the immune system was looking for H3N2 due to previous infection with the H1N1 virus and quickly overcame it.

This work would have to be completed to better understand immunological mechanisms, but so far it has been possible to understand how infections, especially Kovid-19, affect people according to their past performance, and thus more Develop targeted interventions.