Figure 2

Compartmentalized macrophage infectivity for brain and immune tissue envelopes. Nearly all envelopes amplified from brain tissue efficiently infected primary macrophage cultures. In contrast, envelopes from immune tissue varied in the capacity to infect macrophages with infection ranging from background levels to highly efficient infection for a small minority. Infectivity is presented as FFU/ml and was derived from titers averaged from at least two assays using macrophage prepared from different donors.