Figure 3.

Diverse functionality of CD8⁺ T cells and regulatory T cells (Tregs) in patients with SARS-CoV-2-induced disease. During the early-stage of the disease, the activity of CD8⁺ T cells is protective, whereas the cells are hyper-active and amplify inflammatory responses associated with cytokine storm and lung damage at late stage of the disease. Tregs have their own pros and cons during each disease stage. At early stage, Tregs dampen systemic inflammation, but they can hamper anti-viral defense systems. At late stage of the disease, Tregs protect body organs from inflammatory-related damages, but they may promote immunosuppression and further persistence and delayed clearance of the virus.