To assess the involvement of Meth induced IL-1β in enhanced HIV-1 replication, we blocked IL-1 signaling using exogenous IL-1RA. Cells were pretreated with IL-1RA and/or Meth, for 24 h before exposure to HIV-1; IL-1RA and Meth were then administered daily. When HIV-1 infected CD4+ T-cells were co-treated with IL-1RA and Meth, the effect of Meth on enhancing HIV-1 replication was significantly attenuated in a dose dependent manner. We observed that while 200 ng/mL IL-1RA was sufficient to reduce the effect of Meth on HIV-1 replication, virus replication in these cells was still significantly higher than in HIV+ cells (Figure 5F). However, when cells were treated with higher concentrations of IL-1RA (400 ng/mL) prior to Meth treatment, HIV-1 replication was significantly inhibited (Figure 5F). Notably, when HIV-1 infected CD4+ T-cells were treated with IL-1RA alone, there was no change in HIV-1 replication (Figure S1A).