Human microglia activate lymphoproliferative responses to recall viral antigens.
The capacity of adult human microglia to activate memory T-lymphocyte responses to recall viral antigens in autologous peripheral blood lymphocytes (PBL) was examined using measles and influenza viruses. Microglia and peripheral blood macrophages were isolated form 6 patients who underwent surgical brain biopsies. Microglial cultures readily expressed high levels of HLA class II molecules under basal culture conditions. However, compared to macrophages, microglia appeared to express much lower levels of CD45, a phenotype that has been associated with the ability of rat brain macrophage/microglia to present antigen. PBL were depleted of macrophages (D-PBL) and the efficacy of the depletion was assessed by a reduction in the T-cell response to concanavalin A. D-PBL were reconstituted with macrophages, microglia, or in some cases microglia pretreated with interferon-gamma (IFN gamma). It was observed that microglia were as efficient as macrophages in presenting viral antigens. Pretreatment of microglia with IFN gamma did not enhance further antigen presentation. Oligodendrocytes which lack constitutive or inducible HLA class II molecules failed to present viral antigens. The results have implications of the direct function of microglia as perpetuators and possibly initiators of immune responses to virus infection in the central nervous system compartment.
Dhib-Jalbut
S
S
Department of Neurology, University of Maryland School of Medicine, Baltimore 21201, USA.
Gogate
N
N
Jiang
H
H
Eisenberg
H
H
Bergey
G
G
D000328:Adult; D017951:Antigen Presentation / Q000276:immunology; D000956:Antigens, Viral / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D002478:Cells, Cultured / Q000276:immunology / Q000378:metabolism; D005434:Flow Cytometry; D006684:HLA-DR Antigens / Q000378:metabolism; D006801:Humans; D007156:Immunologic Memory / Q000276:immunology*; D017493:Leukocyte Common Antigens / Q000378:metabolism; D008264:Macrophages / Q000276:immunology / Q000821:virology; D008459:Measles virus / Q000276:immunology*; D017628:Microglia / Q000276:immunology* / Q000821:virology; D004676:Myelin Basic Protein / Q000276:immunology; D009975:Orthomyxoviridae / Q000276:immunology*
D000956:Antigens, Viral; D006684:HLA-DR Antigens; D004676:Myelin Basic Protein; D017493:Leukocyte Common Antigens