Ferritin immunohistochemistry as a marker for microglia

Abstract

An immunohistochemical analysis of formalin-fixed, paraffin-embedded brain sections was performed with antisera against holoferritin and the light(L)-subunit of ferritin. Sections immunostained using anti-glial fibrillary acidic protein (GFAP), Ricinus communis agglutinin-1 (RCA-1) stain for microglia and iron stain (Berlin blue stain) were compared. The L-subunit of ferritin was purified from normal human spleen according to the modified scrapie-associated fibrils purification, and the anti-serum was raised in a rabbit. Both ferritin antisera positively stained resting and, more markedly, reactive microglia, both of which were also stained with RCA-1 but not with GFAP. Ferritin-positive resting microglia were seen more abundantly in cerebral and cerebellar cortices than in white matter. The advantages of ferritin antisera over RCA-1 are as follows. (1) RCA-1 heavily stains blood vessels, while anti-ferritin does not, hence the microglial cells are more readily visualized with ferritin immunohistochemistry. (2) Reactive microglia and macrophages are more strongly stained with anti-ferritin. (3) The staining intensity of ferritin is independent of the length of tissue fixation in formalin. However, anti-ferritin is inferior to RCA-1 in staining resting microglia with a scanty cytoplasm, especially in the white matter, probably because the former recognizes cytoplasmic components, while the latter recognizes cell membrane. Iron stain only gave a reaction to microglial cells in brains with neurosyphilis and to hemosiderin-laden macrophages. Thus, in addition to RCA-1, ferritin antisera are useful as a microglia marker in formalin-fixed, paraffin-embedded sections.

The dentate nucleus in Friedreich’s ataxia: the role of iron-responsive proteins

“…Immunocytochemical detection of ferritin has been used for the identiWcation of microglia in various human brain disorders [10,15] but is probably less useful for "resting" microglia. The number of microglia in sections of the normal human dentate nucleus is variable [16] but greater abundance (Fig.…”

Evaluation of the specificity and sensitivity of ferritin as an MRI reporter gene in the mouse brain using lentiviral and adeno-associated viral vectors

“…The MRI background contrast induced by a control LV is reduced in immune-deficient mice As ferritin is a marker for reactive microglia, 28 infiltration of these phagocytic cells at the injection tract might contribute to the background contrast seen on MRI after LV injection as also indicated by histology. To test this hypothesis, a control LV (LV-eGFP-T2A-fLuc) was injected into the right striatum of NOD-SCID immune-deficient mice.…”

Subpopulation of nestin positive glial precursor cells occur in primary adult human brain cultures

“…Oligodendroglial cells were characterized by antibodies to GalC (clone mGalC, 1:10, BoehringerMannheim Wien) and to O4 antigen (clone 81, 1:10, Boehringer-Mannheim Wien). Microglial cells were defined as immunoreactive with antibodies to CD11c (clone BU15, 1:50, Immunotech) (Williams et al 1992) and polyclonal sera to ferritin (1:50, Sigma) (Kaneko et al 1989). Neuronal cells were identified with antibodies to MAP2 (clone HM-2, 1:50, Sigma), N-CAM (clone NCAM-OB11, 1:50, Sigma), and NF (clone NF-01, 1:100, Exbio, Prague).…”