Lectin binding by macroglial and microglial cells in the brains of young normal and myelin-deficient (md) mutant rats.
To distinguish macroglia (oligodendrocytes and astrocytes) from microglia in the brain, 'markers' that have been used in previous studies include carbonic anhydrase II (CAII) immunoreactivity for macroglia, and Ricinus and Bandeiraea (BS-I) lectins for microglia. However, in rats < 1 week of age, many cells stained intensely with both anti-CAII and the labelled BS-I lectin. If some of the BS-I+/CAII+ cells were macroglia, and not microglia, BS-I should no longer be regarded as specific for microglia. To confirm or rule out that possibility, lectin histochemistry and double immunofluorescence staining were performed in tissue from the brains of normal young rats and from the microglial cell-enriched brains of myelin-deficient mutant rats. BS-I+/CAII- cells were found and examined. The BS-I+/CAII- cells resembled macrophages and microglia and did, indeed, differ in sizes and shapes from the BS-I+/CA+ cells. The BS-I+/CA+ cells appeared to represent CAII+ putative oligodendrocyte precursors described previously. Although less obvious, a lectin-binding structure was also observed in astrocytes. Lectins may cross-react with macroglial glycoproteins. For example, a glycoprotein found in oligodendrocytes and myelin, the myelin-associated glycoprotein (MAG), is related to the Ig superfamily and cell adhesion molecules. Therefore, it is cautioned that lectins and antibodies against members of the latter families of proteins should be used as cell-type specific markers only if other parameters are also examined.
Cammer
W
W
Department of Neurology, Albert Einstein College of Medicine, Bronx, NY 10461.
Zhang
H
H
D000375:Aging / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D001921:Brain / Q000166:cytology / Q000254:growth & development / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D037102:Lectins / Q000378:metabolism*; D009185:Myelin Proteins / Q000172:deficiency*; D009457:Neuroglia / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D011922:Rats, Mutant Strains; D017208:Rats, Wistar
D037102:Lectins; D009185:Myelin Proteins