Figure 1.

SARS-CoV-2 infection and T cell response. SARS-CoV-2 infects the respiratory tract by binding to the ACE2 surface receptor. Following entry via membrane fusion, it releases its viral genome in the cytoplasm. Using the host cell machinery, viral genome replication, and subgenomic transcription generate essential components needed for the virus to pack together. After the maturation of the virion, it is released from the host cell through exocytosis. When the viruses are captured and processed by antigen-presenting cells (APC), the T cells, either CD4⁺ or CD8⁺, are activated and secrete cytokines (IFNγ, TNFα, Granzyme B) to defend against viruses.