Figure 6B depicts a resting microglial cell on the left (so-called ramified structure, normally observed within the tissue), which upon infection becomes activated and rounded (on the right). The co-culture experiments demonstrated that monocytes isolated from mice lacking Fas- or FasL did not undergo apoptosis upon contact with uninfected or HSV-2-infected astrocytes or mixed glial cultures (Figure 6C). This evidence concerns the gene FAS and infection.