Antibodies to CD11b, CD68, and lectin label neutrophils rather than microglia in traumatic and ischemic brain lesions.
Resident quiescent microglia have been thought to respond rapidly to various pathologic events in the brain by proliferating and producing many bioactive substances, including proinflammatory cytokines and nitric oxide (NO). In this study, we investigated the reaction of microglia in traumatic and ischemic lesions caused by stab wounds and the transient 90-min occlusion of middle cerebral artery in a mature rat brain. Although many Iba1(+) resident microglia underwent apoptotic degeneration in the lesion core within 24 hr after the onset of the brain insult as revealed by TUNEL staining, numerous small, round, isolectin B4(+)/CD11b(+)/CD68(+) cells were localized in the lesion core. These small, round cells with diameters of 7-9 mum and polymorph nuclei expressed neutrophil-specific elastase, alkaline phosphatase, and platelet-activating factor receptor. Accordingly, they were not activated microglia but neutrophils. Immunohistochemical staining with antibodies to inducible NO synthase (iNOS) showed that most iNOS(+) cells were neutrophils. The results from spatial and kinetic analyses using RT-PCR and immunoblotting were consistent with the immunohistochemical observations. These results suggest the necessity of reevaluating the traditional view on the roles of activated microglia in severe neuropathologic events. Note that the traditional microglial markers isolectin B4, CD11b, and CD68 are not specific for microglia, particularly in a pathologic brain.
Matsumoto
Hiroaki
H
Department of Neurosurgery, Graduate School of Medicine, Ehime University, Ehime, Japan.
Kumon
Yoshiaki
Y
Watanabe
Hideaki
H
Ohnishi
Takanori
T
Shudou
Masachika
M
Ii
Chisato
C
Takahashi
Hisaaki
H
Imai
Yoshinori
Y
Tanaka
Junya
J
D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D000906:Antibodies; D015703:Antigens, CD / Q000032:analysis / Q000276:immunology / Q000378:metabolism; D015214:Antigens, Differentiation, Myelomonocytic / Q000032:analysis / Q000276:immunology / Q000378:metabolism; D000954:Antigens, Surface / Q000276:immunology*; D015415:Biomarkers / Q000032:analysis / Q000378:metabolism; D020520:Brain Infarction / Q000276:immunology / Q000473:pathology / Q000503:physiopathology; D001930:Brain Injuries / Q000276:immunology* / Q000473:pathology / Q000503:physiopathology; D002545:Brain Ischemia / Q000276:immunology* / Q000473:pathology / Q000503:physiopathology; D018845:CD11 Antigens / Q000032:analysis / Q000276:immunology / Q000378:metabolism; D002634:Chemotaxis, Leukocyte / Q000276:immunology*; D005260:Female; D020244:Infarction, Middle Cerebral Artery / Q000276:immunology / Q000473:pathology / Q000503:physiopathology; D019272:Leukocyte Elastase / Q000378:metabolism; D008297:Male; D017628:Microglia / Q000276:immunology*; D009504:Neutrophils / Q000276:immunology*; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D037121:Plant Lectins / Q000276:immunology; D010980:Platelet Membrane Glycoproteins / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism; D000097382:CD68 Molecule
D000469:Alkaline Phosphatase; D000906:Antibodies; D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D000954:Antigens, Surface; D015415:Biomarkers; D018845:CD11 Antigens; D019272:Leukocyte Elastase; D052247:Nitric Oxide Synthase Type II; D037121:Plant Lectins; D010980:Platelet Membrane Glycoproteins; D043562:Receptors, G-Protein-Coupled; C067980:CD68 antigen, human; D000097382:CD68 Molecule; C045475:Griffonia simplicifolia lectins; C039351:platelet activating factor receptor