29 Nov 2021
Setting it Straight: Viruses, Vaccines and COVID-19: into the lymph nodes
Our very personal experience of COVID-19 begins when we breathe in air containing the SARS-CoV-2 virus and it attaches, via the receptor binding domain (RBD) on its projecting spike (S) protein, to an ACE2 molecule on the surface of a nasal epithelial cell. That attachment allows the virus particle (virion) to enter the cytoplasm, take off its protein/lipid ‘coat’ and free the RNA that enables the virus to replicate itself many times over (#82). As newly-made virions are released from the virus-producing cell ‘factory’, some will go on to infect other cells in us or (after being coughed or sneezed out) in others and some will drain in nasal mucus to the lymphoid tissue of the tonsils and adenoids (if they haven’t been surgically removed) and the cervical lymph nodes (CLNs) in our neck. Either there, or along the way, virus will also have been taken up by macrophages and dendritic cells (DCs), the main antigen-presenting cells of our immune system.