Notably, this is the first known application of the EdU thymidine analog to assess human T cell activation and DNA replication in response to several physiologically relevant stimuli,66,67 including common anti-CD3/anti-CD28/anti-CD2 polyclonal activators, influenza vaccine, M. avium intracellulare, and recombinant trimeric SARS-CoV-2 spike protein. The gene discussed is CD28; the disease is influenza.