The B cells that fight infections retain better immune memory of the coronavirus spike protein in patients recovering from less severe cases of COVID-19 compared to those recovering from a severe one COVID-19. To declare this in one of their studies are the results of a study by the scientists of theUniversity of Texas Health Science Center in San Antonio.
The results of the Research have been published in the scientific journal PLOS ONE.
Immune memory after covid19: here are the research results
Evelien Bunnik, Ph.D., corresponding author of the article, said the findings suggest subtle differences in the quality of immune memory based on the severity of the COVID-19. Dr. Bunnik is an assistant professor of microbiology, immunology, and molecular genetics at the health science center, also known as UT Health San Antonio.
The study focused on memory B cells that react against the SARS-CoV-2 spike protein. Blood samples were analyzed one month after onset of symptoms and five months after onset
After one month, a significant percentage of peak-specific B cells were active. However, samples from eight individuals who recovered from less severe disease showed greater expression of markers associated with lasting B-cell memory than individuals who recovered from severe disease, the authors explained. The scorers include T-bet and FcRL5.
T-bet-positive and spike-specific B cells nearly disappeared from the blood samples five months after the onset of symptoms. Overall, a more dysfunctional B-cell response is observed in severe disease, hence a less lasting immune memory.
Non-severe cases were defined as not requiring supplemental oxygen or invasive ventilation, while severe cases required invasive mechanical ventilation or extracorporeal membrane oxygenation (ECMO).
“The definition of severe disease was made on the basis of the need for mechanical ventilation or ECMO, because this distinguishes the most critically ill patients, who are more likely to develop impaired immune responsesSaid the senior author of the study Thomas Patterson, MD, professor and chief of infectious diseases at UT Health San Antonio guiding COVID-19 care at the clinical partner University Health.
Study participants were enrolled in the Adaptive COVID-19 Treatment Trial (ACTT) -1 or ACTT-2 clinical trials. The samples were from university healthcare patients co-enrolled in UT Health San Antonio’s COVID-19 repository.
“The increase in the percentage of B cells associated with long-lasting immunity in non-severe COVID-19 patients may have consequences for long-term immunity against SARS-CoV-2 reinfection or the severity of the resulting disease “, the authors concluded.
Correlates of protective immunity to a pathogen are measurable signs that reliably identify individuals as being protected from specific outcomes, such as infection, transmission risk, or disease outcome. After SARS-CoV-2 infection or vaccination, it is adaptive immune memory that ideally provides long-term protection.
The adaptive immune response mainly comprises memory B cells which produce different classes of antibodies to neutralize virus or virus infected cells and memory T cells which support antibody production and also have a direct role in killing cells infected with virus. Although there is evidence of immune responses of both B cell and immune memory T cells in individuals infected with SARS-CoV-2 and vaccinated individuals, clear correlates for protective immunity have yet to be defined.
In the absence of definitive correlates of protective immunity, the presence of neutralizing antibodies against SARS-CoV-2 provides the best current indication for protection against reinfection for previously infected individuals or rupture infection in vaccinated individuals. The S1 domain of the SARS-CoV-2 spike protein includes the receptor-binding domain (RBD) and antibodies that target this critically damage the entry of virus cells.
Numerous studies have shown that the neutralization capacity of polyclonal antibodies in serum is positively correlated with anti-spike IgG or anti-RBD IgG [2]. The S1 domain of the SARS-CoV-2 spike protein includes the receptor-binding domain (RBD) and antibodies that target this critically damage the entry of virus cells. Numerous studies have shown that the neutralizing ability of polyclonal antibodies in serum is positively correlated with anti-spike IgG or anti-RBD IgG.
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