Microglial localization of alpha-interferon receptor in human brain tissues.

The localization of the alpha-interferon receptor (alpha-IFNR) was examined in human brain tissues from neurologically normal, Alzheimer's disease (AD) and cerebral infarction cases, using one antibody (IFNaR3) which preferentially recognizes alpha 2-IFN receptor and a second antibody (anti-p40) which recognizes the soluble alpha-IFN alpha/beta receptor. In all cases, microglial cells were stained with the antibodies. In infarct brains, macrophages were intensely labeled for alpha-IFNR. The anti-p40 antibody also showed capillary staining which might be due to residual blood plasma. On Western blots, IFNaR3 recognized only a 210 kDa alpha-IFN/receptor complex, indicating its localization in microglial cells. The anti-p40 antibody recognized this complex as well as four other major materials of lower molecular weight. These results suggest that alpha-IFNR protein is constitutively expressed in microglial cells.