ePortfolio #2: T cells and COVID Vaccine

This research focuses on the significance of T cell responses in producing protective immunity against SARS-CoV-2, particularly in the setting of COVID-19 immunization. The main focus of most COVID-19 vaccination studies has been on neutralizing antibody (NAb) responses; cellular immunity has received less attention, as this research also highlighted. As we covered in class, neutralization is the best defense against infection, but it isn’t perfect, which is why this makes perfect sense that most research on COVID-19 vaccines has focused on neutralizing antibody responses instead of cellular immunity.  In addition, the study investigates the potential significance of T cell responses in the context of vaccine protection against severe COVID-19, especially in the case of viral strains that partially evade neutralizing antibody detection.

Some of the study’s significant findings include the involvement of T cell responses in vaccine protection against severe COVID-19, particularly in circumstances where viral variations may avoid neutralizing antibody identification. The main way that antibodies, especially neutralizing antibodies, work is by preventing the virus from entering the host cell. T cells, on the other hand, can identify infected cells and act quickly to stop the spread of the virus once the infection has started. T cells can quickly stop the spread of infection after it has already started, but they are ineffective in stopping the virus from infecting host cells in the first place. T cell responses become especially crucial in situations when neutralizing antibodies might not be able to completely stop the spread of infection or might not be able to identify certain viral variations. T cells may help in stopping the development of serious illness since they are perfectly adapted to eradicate virus-infected cells. In contrast to neutralizing antibodies, which may gradually lose their strength, memory T cells can offer a long-lasting defense. SARS-CoV-2–specific memory T cells endure and can support long-term immunity even after vaccination or infection. Evidence from observation, such as research on B cell deficiency in cancer patients, studies on CD8+ T cell reduction in macaques, and vaccination failures linked to a deficiency of Omicron-specific CD8+ T cells, supports the idea that T cell responses play a role in defense against serious illness (1).

We currently know from this paper that the ability of T cell responses, involving CD4+ and CD8+ T cells, to protect against severe COVID-19 illness is essential for vaccination protection. T cell responses are especially crucial when viral variations escape detection by neutralizing antibodies (NAbs) is one of the few things. T cells, in contrast to antibodies, are unable to stop an infection from starting, but once it has started, they can act quickly to stop the virus’s reproduction and spread. T cell immunity is thought to be critical in stopping the advancement of severe illness. Memory T cells are among the T cell responses that endure long after an infection or immunization, possibly offering long-term protection. Serum antibody titers may quickly decline, but memory T cells are incredibly resilient (1).

One of the findings from another study demonstrated that Individuals with less severe symptoms were more likely to have higher antigen-responsive T cell percentages of both CD4+ and CD8+. This is another knowledge we currently have about the T cell response to the current COVID-19 vaccine. We also currently know that T cell receptors identify epitopes that are processed and displayed on major histocompatibility complex (MHC) molecules, in contrast to B cell receptors, which can directly recognize their antigens. Human MHC molecules, or HLAs, are incredibly polymorphic, which results in various T-cell responses in different people (2). According to available data, T cells specific to SARS-CoV-2 are necessary for the elimination of the virus, may guard against infection even in the absence of seroconversion, have a strong memory, and aid in the identification of viral variations (3).

References

1.WHERRY , E. J., & BAROUCH , D. H. (2022, August 18). T cell immunity to covid-19 vaccines | science – AAAS. https://www.science.org/doi/10.1126/science.add2897

2.Lu, X., & Yamasaki, S. (2022, November 29). Current understanding of T cell immunity against SARS-COV-2. Inflammation and regeneration. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9706904/

3.Moss, P. (2022, February 1). The T cell immune response against SARS-COV-2. Nature News. https://www.nature.com/articles/s41590-021-01122-w