Transcriptional profile comparison between mock-, Fr57E- and FrCasE-infected microglia identifies a very small number of differentially expressed genes. Average normalized expression levels for the genes and ESTs represented on the Affymetrix 430A mouse chip were compared for each condition and plotted as pairwise comparisons. Panel A shows comparisons between MLV – infected and mock-infected control microglia. Note that very few genes with normalized intensity values >100 were found off the diagonal (which represents equal expression). Panel B shows a comparison between microglia infected with the non-neurovirulent virus Fr57E and the highly neurovirulent virus FrCasE. The identification of a few differentially expressed genes (circled) is provided. A complete listing of the differentially expressed genes is provided in tables 2-4.