A group of Harvard medical school reported about why the humoral response (antibody-centric adaptive immune response) is non-persistent in the new coronavirus (COVID-19)?
In addition to innate immunity, adaptive immunity centered on antibodies plays an important role in the elimination of foreign substances such as viruses that invade the living body. In the early stages of infection, low affinity IgG antibodies are produced, but IgG antibodies produced over time mature and increase affinity for antigens. This is because B cells that produce high affinity antibodies differentiate in germinal center (a small structure formed in the immune system, such as the spleen and lymph nodes, during the immune response). In the early stages of infection, antigen-specific B cells quickly differentiate into plasma cells to produce low-affinity antibodies, but some B cells express transcription factor Bcl6 (Bcl-6 Tfh cells) to form the germinal center.
In fact, in COVID-19, the fact that the formation of this germinal center is suppressed seems to be the cause of the title. Why is the formation of the cup center suppressed? The detailed mechanism is not known, however, it is said that excessive production of cytokines such as TNF-α suppresses the differentiation of Bcl6-Tfh cells and results in loss of germinal center.
This behavior seems to occur not only in COPID-19, but also in Ebora, Marburg disease, and H5N1 influenza.