RNA vaccines based on the classic SARS-CoV-2 coronavirus strain produce immune cells that recognize mutant strains of the virus, as scientists from Johns Hopkins University (USA) found, reported in an article published in the Journal of Clinical Investigation.
According to MedicalXpress, the vaccine causes the body to produce CD4 + T-lymphocytes (or T-helpers), which activate B-lymphocytes that recognize antigens – proteins on the surface of infected cells, including those affected by SARS-CoV-2 viruses. Immature B cells are activated by helper T cells and become either plasma cells that produce antibodies or memory B cells that store information about the antigen in order to develop a faster response to infection in the future. In the case of SARS-CoV-2, the antigen is a spike protein (S-protein) that forms spikes on the surface of the virus.
Pfizer-BioNTech and Moderna virus RNA vaccines present the S-protein genetic sequences to the vaccinated person’s immune system to recognize the spike protein and initiate the production of antibodies against SARS-CoV-2.
The researchers analyzed blood samples from 30 healthy healthcare workers and laboratory donors who had not previously tested positive for SARS-CoV-2 before and after two doses of vaccines. The isolated CD4 + T cells were tested on various components of the original SARS-CoV-2 strain as well as the three common cold-causing coronaviruses. It turned out that the vaccinated had developed a broad immune response to 23 peptide fragments of the S-protein, only four of which were affected by mutations, which resulted in the emergence of new strains in the UK and South Africa. Thus, vaccines should provide protection even against mutant forms of the coronavirus.
Scientists also discovered a spike protein response from one of the common cold coronavirus HCoV-NL63, which may be due to the fact that it shares many areas with the coronavirus protein.