Reactivity of sera from humans occupationally exposed to SFVspm and SFVmac. Cell lysates were generated from uninfected HT1080 cells (UN), cells infected with SFVmac (MAC), or cells infected with SFVspm (SPM). Western blot assays were performed using plasma (1:20) collected from primatologists (APH) with documented exposures to NWM; an anti-GAPDH antibody (1:3,000) was also used. Representative Western blots are shown for the 8 of the 116 APH samples that were seropositive (APH 3, 10, 25, 48, 71, 75, 84, and 111) in addition to a Western blot showing results with plasma (1:20) from an individual with no known exposures to nonhuman primates (NHS) and an individual from Bangladesh known to be infected with SFVmac only (BGH 63).