T cells are a part of our immune system that focuses on specific foreign bodies...ie. rather than attacking any antigen that comes along, the T cells wait for a specific antigen.
From the day we are born the T cells start developing immunity for common pathogens and as we grow up long term memory T cells gets established .
Usually our antibodies can prevent infection, but when antibody counts get low – years after infection or vaccination – some cells will inevitably be infected. In this case, T cells come to the rescue. Cytotoxic T cells can sense that a cell is infected and kill it.
These T cells sense infected cells by viral peptides that are presented by major histocompatibility complex (MHC) molecules on the plasma membrane. The function of the MHC molecules is to bind peptide fragments derived from pathogens and display them on the cell surface for recognition by the appropriate T cells.
There are several types of T cells but only two of them the CD4 helper T cells and CD8 cytotoxic cells were studied by a group of researchers at the Center for Infectious Disease and Vaccine Research, La Jolla Institute for Immunology, on the effects of Covid-19.
What they found was that with the original Wuhan strain, and with variants B.1.1.7, B.1.351, P.1, and CAL.20C, there's only little difference in the ability of T cells to recognize the peptides. This means that the T cells can recognize any variant and clear the infected cells.
During the last one year many didn't study the effects of the T cells and the vaccine developers when ahead targeting the spike protein. These new findings will make the scientists to take a second look to create a new generation of vaccines to include viral proteins other than the spike protein. This also implies that the inactivated vaccines will perform better in the long run.
It's too complex to explain in a short rant but this is the summary of their recent publication.
"The emergence of SARS-CoV-2 variants highlighted the need to better understand adaptive immune responses to this virus. It is important to address whether also CD4+ and CD8+ T cell responses are affected, because of the role they play in disease resolution and modulation of COVID-19 disease severity. Here we performed a comprehensive analysis of SARS-CoV-2-specific CD4+ and CD8+ T cell responses from COVID-19 convalescent subjects recognizing the ancestral strain, compared to variant lineages B.1.1.7, B.1.351, P.1, and CAL.20C as well as recipients of the Moderna (mRNA-1273) or Pfizer/BioNTech (BNT162b2) COVID-19 vaccines. Similarly, we demonstrate that the sequences of the vast majority of SARS-CoV-2 T cell epitopes are not affected by the mutations found in the variants analyzed. Overall, the results demonstrate that CD4+ and CD8+ T cell responses in convalescent COVID-19 subjects or COVID-19 mRNA vaccinees are not substantially affected by mutations found in the SARS-CoV-2 variants."
From the day we are born the T cells start developing immunity for common pathogens and as we grow up long term memory T cells gets established .
Usually our antibodies can prevent infection, but when antibody counts get low – years after infection or vaccination – some cells will inevitably be infected. In this case, T cells come to the rescue. Cytotoxic T cells can sense that a cell is infected and kill it.
These T cells sense infected cells by viral peptides that are presented by major histocompatibility complex (MHC) molecules on the plasma membrane. The function of the MHC molecules is to bind peptide fragments derived from pathogens and display them on the cell surface for recognition by the appropriate T cells.
There are several types of T cells but only two of them the CD4 helper T cells and CD8 cytotoxic cells were studied by a group of researchers at the Center for Infectious Disease and Vaccine Research, La Jolla Institute for Immunology, on the effects of Covid-19.
What they found was that with the original Wuhan strain, and with variants B.1.1.7, B.1.351, P.1, and CAL.20C, there's only little difference in the ability of T cells to recognize the peptides. This means that the T cells can recognize any variant and clear the infected cells.
During the last one year many didn't study the effects of the T cells and the vaccine developers when ahead targeting the spike protein. These new findings will make the scientists to take a second look to create a new generation of vaccines to include viral proteins other than the spike protein. This also implies that the inactivated vaccines will perform better in the long run.
It's too complex to explain in a short rant but this is the summary of their recent publication.
"The emergence of SARS-CoV-2 variants highlighted the need to better understand adaptive immune responses to this virus. It is important to address whether also CD4+ and CD8+ T cell responses are affected, because of the role they play in disease resolution and modulation of COVID-19 disease severity. Here we performed a comprehensive analysis of SARS-CoV-2-specific CD4+ and CD8+ T cell responses from COVID-19 convalescent subjects recognizing the ancestral strain, compared to variant lineages B.1.1.7, B.1.351, P.1, and CAL.20C as well as recipients of the Moderna (mRNA-1273) or Pfizer/BioNTech (BNT162b2) COVID-19 vaccines. Similarly, we demonstrate that the sequences of the vast majority of SARS-CoV-2 T cell epitopes are not affected by the mutations found in the variants analyzed. Overall, the results demonstrate that CD4+ and CD8+ T cell responses in convalescent COVID-19 subjects or COVID-19 mRNA vaccinees are not substantially affected by mutations found in the SARS-CoV-2 variants."
