IFNB1 and infection: While multiple cell types may be contributing to IFN-β production, these data are consistent with previously published results showing high levels of IFN-β production by pDCs in the lymph nodes of SIV-infected SMs during the acute phase of infection [21], and indicate that, in SMs, the ability to produce additional type I IFNs after TLR7 stimulation is largely intact.