FIG 2.

Mechanisms of RSV T-cell interference as a potential immune evasion strategy. RSV infection is associated with an initial systemic T-cell lymphopenia that is quantitatively associated with disease severity. RSV may interfere with T-cell responses by inducing apoptosis (CD4⁺ and CD8⁺ T cells) (A), inducing increased expression of the programmed cell death 1 (PD-1) protein, which is inhibitory to activated T cells (CD8⁺ T cells) (B), and promoting activation of the mammalian target of rapamycin (mTOR) pathway, thus preventing memory CD8⁺ T-cell formation (C).