Researchers at Columbia Medical University, USA, published a paper in the journal ‘Science Immunology’
Long-term ‘immune memory’ storage in lungs and lymph nodes
Older people react similarly
Long-term immunity to COVID-19 depends on how well memory B cells remember the epitope of the novel coronavirus.
Unlike blood circulating antibodies, which begin to weaken after a few months, memory B cells live much longer and immediately produce neutralizing antibodies when the new coronavirus invades again.
The reality that many of those vaccinated against COVID-19 cannot avoid ‘breakthrough infection’ is because the current vaccine does not sufficiently induce long-term immune memory.
Researchers at Rockefeller University in the United States recently published a study in the journal ‘Nature’ that showed that memory B cells, which are produced when infected with the novel coronavirus, show excellent efficacy in forming long-term immunity.
The research team also reported that memory B cells generated during new corona infection produce antibodies that neutralize better than when they received the mRNA vaccine.
Confirmation of ‘germ center’ that produces antibodies and B cells, lasting at least 6 months
Another study found that long-term immune memories are stored in the lungs and surrounding tissues when recovering from infection with the new coronavirus.
Immune memories once infected with the corona are stored in the T cells and B cells of the lungs and surrounding lymph nodes.
The results of this research conducted by Donna Faber, a professor of microbiology and immunology at Columbia Medical University, were first published online on the 7th (local time) ahead of the publication of a paper in the journal ‘Science Immunology’.
Professor Shane Croti and Professor Alessandro Sete of the La Jolla Institute of Immunology also participated in the study.
Professor Faber’s team confirmed that the germinal center was present in the lung-related lymph nodes of patients recovering from the novel coronavirus until six months later.
It is noteworthy that the germinal center is maintained for such a long period even in elderly recovering patients.
The germinal center refers to a microstructure that is temporarily formed in lymph nodes and spleen in response to T-cell-dependent antigens when infected with a pathogen.
Antibody-producing plasma cells and memory B cells must be produced within the germinal center for the defense mechanism against re-infection to work.
The research team also found that germinal center B cells and cystic helper T cells that identify the novel coronavirus coexist in lung-associated lymph nodes. This type of T cell promotes the differentiation of B cells.
It is the first time that it has been proven that the center of gravity is maintained for a long period of time for a new coronavirus infected person, even for an elderly person.
When germinal center B cells exist for such a long time, many circulating antibodies are maintained for a long time and the immune response continues to mature.
The emergence of the novel coronavirus has provided immunologists with a paradoxical opportunity. This will allow us to study how older people respond to new pathogens.
The research team analyzed tissue samples from four people who recovered after being infected with the new coronavirus and compared them with non-infected people.
Those with an age gap of 11 to 74 who died from other causes last year before a COVID-19 vaccine was available, donated their organs and tissues while they were still alive.
Faber’s team has been developing these samples for the past decade or so to study how tissue, not blood, builds immunity.
As a result of the analysis, it was found that, beyond the age of 40, T cells that remember encounters with new pathogens do not produce many.
Professor Faber said, “As we age, most of our immune defense relies on memory cells (which are already formed),” said Professor Faber.
“Strong immune memory against new pathogens, even in the elderly”
The study found that strong immune memories against new pathogens are also formed in the elderly.
This suggests that older adults vaccinated against COVID-19 may provoke a more effective immune response than thought.
“We know that the immune system declines with age, but some people have a long-lasting, long-lasting immune memory response even in their 70s,” said Faber. did.
If the results of this study are utilized well, it is expected that the design and inoculation procedure of the COVID-19 vaccine can be improved as a method of promoting the type of immune memory generated by the natural infection of the novel coronavirus.
“The results of this study show that vaccines must target immune memory cells in the lungs and associated lymph nodes to enhance defense against the virus,” Faber said. can do it,” he pointed out.
“Previous experiments in mice infected with influenza confirmed that memory T cells in the lungs are required for optimal protection against respiratory infections,” he said. “This study strongly suggests that humans may do the same.”
By Kim Chae-hyun, staff reporter [email protected]