Once in our body, SARS-CoV-2, the virus that causes COVID-19, forces the body’s innate immune system to activate. However, the innate immune system response typically is deemed unsuccessful due to the complexities of the virus’s structural components, which then paves way for the body’s adaptive immune response to initiate. As we learned in Biology, adaptive immune response begins with a macrophage engulfing SARS-CoV-2 through phagocytosis. Then, the MHC proteins present on the macrophages, white blood cells that surround and kills microorganisms, remove dead cells, and stimulates the action of other immune system cells,” display the antigen on the surface, creating a ‘wanted’ poster for the immune system (Cancer.Gov). We also learned that eventually, a T-Helped cell comes along and binds to the displayed antigen, which activates the T-Helper cell which fosters the secretion of interleukin, a cytokine. Finally, both B and T cells are stimulated, which then begin the process of fighting off the virus, along with preventing reinfection. One of the cells that assists in the preventing reinfection are B-Plasma Cells, which are, “antibody-producing immune cells [that] rapidly multiply and circulate in the blood, driving antibody levels sky-high”(WashU School of Medicine).
One crucial step in determining a person’s ability to fight reinfection is testing to see if antibody secretion has either occurred or is currently occurring. While typical blood samples will suffice, “the key to figuring out whether COVID-19 leads to long-lasting antibody protection, Ellebedy [ PhD, and associate professor of pathology & immunology] realized, lies in the bone marrow”(WashU School of Medicine). The B Lymphocytes, which initiate a humoral response, mature in the bone marrow, and so, to determine the prevalence of antibody secreting cells, bone marrow samples must be received from past COVID-19 patients. To determine if antibody production increases after the body completes its fight against, Ellebedy collected blood samples and “As expected, antibody levels in the blood of the COVID-19 participants dropped quickly in the first few months after infection and then mostly leveled off, with some antibodies detectable even 11 months after infection” (WashU School of Medicine). However, people who exhibited mild cases of COVID-19, meaning that their body removed the virus after two to three weeks, antibodies continue to secrete antibodies, and will continue for an indefinite time period.
One problem introduced was rooted in the mainstream media, which spread a misinterpretation of data, being that “antibodies wane quickly after infection with the virus that causes COVID-19” (WashU School of Medicine). Ellebedy believes that this is a major misinterpretation of data, and actually means that antibody production is continuing inside of the bone marrow. Typically, antibody production plateaus after a certain period of time preceding infection, yet these numbers don’t go to zero.
Ellebedy concludes that this result is highly promising, especially for people who experienced a more severe infection from SARS-CoV-2, because an increased amount of circulating virus cells typically leads to a stronger immune response due to the body being required to secrete more antibody cells. Although she believes that more studies need to undergo in people who experienced moderate to severe infections, and show if they also have the same everlasting antibody production.
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