In order to identify the cellular locus of NKG2D ligand expression in the hippocampus we attempted, unsuccessfully, to immunostain fresh frozen or paraffin-embedded sections of hippocampus after fixation with paraformaldehyde, methanol, or ethanol:acetone. We tested specific anti-Rae1 (clone 186107; 1:25; R&D Systems) and anti-H60 (clone 205326; 1:100; R&D Systems) antibodies as well as a pan-specific NKG2D ligand antibody (goat anti-Rae1; 1:100; Santa Cruz Biotechnology) and the pan-specific NKG2D-Fc chimeric molecule (R&D Systems 139-NK; 1:10). Likewise, we attempted to confirm the expression of the NKG2D ligands at the protein level within the hippocampus by western blot analysis of hippocampal lysates. Of the numerous antibodies tested (same as immunostaining, above), only the anti-H60 antibody (clone 205326; 1:100; R&D Systems) successfully identified a prominent band that was present within the hippocampus only after infection and which was also present in lysate from the YAC-1 NK cell target line ( Figure 3B ). The apparent molecular weight of this prominent band (ca. 50 kDa) matches that described by Hasan and colleagues (Hasan et al, 2005) . The relative difference in mobility between the putative H60 band in the hippocampal lysate and the YAC-1 cell lysate may reflect differential expression of one of the three recently identified isoforms of H60 that share high sequence homology but differ in molecular weight (Takada et al, 2008) . We conclude that NKG2D ligands such as H60 are upregulated at both the transcriptional and translational level within the hippocampus following acute TMEV infection, but we are unable to identify the cells that express these ligands with the currently available immunologic tools.