IFNA1 and HIV-1 infection: Next, we were interested whether a previous HIV-1 infection would affect the IFN-mediated time-dependent regulation of SRSF1. Therefore, we infected THP-1 macrophages with the R5-tropic HIV-1 laboratory strain NL4-3 AD8 16 h before stimulation with IFNα2 or IFNα14.