Differential astrocyte response to Theiler's murine encephalomyelitis virus infection.
OBJECTIVE
We aimed to address if selective astrocyte apoptosis is involved in the lack of murine demyelinating disease following infection by the L*-1 variant of Theiler's virus. In addition, we investigated whether L*-1-infected astrocytes were able to selectively express molecules whose effects would play a role as pathogenic factors.


METHODS
Murine cultured astrocytes were infected with two Theiler viruses, the DA strain and the mutated DA variant L*-1, which does not synthesize the out of frame L* protein.


RESULTS
Neither DA nor L*-1 provoked apoptosis, although they replicated in astrocytes inducing GFAP and iNOS expression, as well as subsequent nitric oxide production. In addition, both viruses caused an enhanced expression of ICAM-1, VCAM-1 and decay accelerating factor (DAF). In this connection, values of VCAM-1 and DAF induced by L*-1 were higher and lower, respectively, than those induced by DA.


CONCLUSIONS
Since no apoptosis was found, such mechanism would not be involved in the lack of TMEV-induced demyelinating disease by L*-1. In contrast, selective expression of VCAM-1 and DAF molecules induced by L*-1 could have a role in virus clearance from the central nervous system.
Pozner
Roberto G
RG
Department of Thrombosis and Haemostasis, Hematological Research Institute, National Academy of Medicine, University of Buenos Aires, Buenos Aires, Argentina.
Berría
Maria I
MI
Negrotto
Soledad
S
Schattner
Mirta
M
Gómez
Ricardo M
RM
D000818:Animals; D017209:Apoptosis; D001253:Astrocytes / Q000378:metabolism / Q000473:pathology* / Q000821:virology*; D018958:CD55 Antigens / Q000032:analysis; D002478:Cells, Cultured; D004679:Encephalomyelitis / Q000453:epidemiology; D015870:Gene Expression; D005904:Glial Fibrillary Acidic Protein / Q000032:analysis; D018799:Intercellular Adhesion Molecule-1 / Q000032:analysis; D051379:Mice; D009569:Nitric Oxide / Q000032:analysis; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D017945:Theilovirus / Q000502:physiology*; D019010:Vascular Cell Adhesion Molecule-1 / Q000032:analysis
D018958:CD55 Antigens; D005904:Glial Fibrillary Acidic Protein; D019010:Vascular Cell Adhesion Molecule-1; D018799:Intercellular Adhesion Molecule-1; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse