TNF-α and IL-10 differentially modulate apoptosis during PRRSV-1 infection of bone marrow-derived dendritic cells

). Early after infection (≤ 24 hpi), infected cells were predominantly non-apoptotic; by 48 hpi, apoptotic bystander cells increased markedly, consistent with a bystander apoptotic process. Neutralizing TNF-α in TNF-α-inducing isolates (3262, 3249) increased the proportion of infected cells and reduced bystander apoptosis, suggesting an antiviral role for TNF-α at the cellular level. In contrast, IL-10 blockade in IL-10-inducing isolates (3262, 2988) increased non-apoptotic infected cells without altering overall infection frequency, suggesting IL-10 modulates apoptotic progression in infected cells. Collectively, these data indicate that TNF-α and IL-10 differentially modulate apoptotic outcomes during PRRSV-1 infection in an isolate-dependent manner.