After intramuscular injection, lipid nanoparticle–mRNA (LNP–mRNA) vaccines are internalized by
somatic cells (for example, muscle cells) and tissue-resident or recruited antigen-presenting cells (APCs). Moreover, LNP–mRNA vaccines can centre draining lymph nodes, where various immune cells reside, including naive T and B cells. Spike antigens expressed in the cytoplasm are degraded by proteasomes and major histocompatibility complex (MHC) class I presents the resultant epitopes to CD8+ T cells. Spike antigens can also be endocytosed by APCs. These antigens are degraded in the lysosomes of APCs and presented by MHC II molecules for CD4+ T cells. In addition, secreted spike antigens can be internalized by B cell receptors and processed for presentation to CD4+ T cells by MHC class II molecules. COVID-19, coronavirus disease 2019; SARS-CoV-2, severe acute respiratory syndrome coronavirus 2; TCR, T cell receptor.
https://www.nature.com/articles/s41578-021-00358-0
人體除咗精同卵,有乜cell唔喺 somatic cells