CD4 and COVID-19: Among these conserved viral proteins, we observed that the early-transcribed non-structural proteins, including NSP-2, NSP-7, NSP-12, NSP-13, and NSP-14, from the RTC region, as well as the structural Nucleoprotein, were selectively targeted by (i) peripheral blood cross-reactive memory CD4+ and CD8+ T cells from asymptomatic COVID-19 patients.