Molecular mechanisms of high-dose antigen therapy in experimental autoimmune encephalomyelitis: rapid induction of Th1-type cytokines and inducible nitric oxide synthase.
High-dose Ag administration induces apoptotic death of autoreactive T cells and is an effective therapy of experimental autoimmune diseases of the nervous system. To explore the role of cytokines in Ag-specific immunotherapy, we analyzed mRNA induction and protein expression for the proinflammatory cytokines TNF-alpha and IFN-gamma, the anti-inflammatory cytokine IL-10, and the cytokine-inducible NO synthase (iNOS) during high-dose Ag therapy of adoptive transfer experimental autoimmune encephalomyelitis (AT-EAE) in the Lewis rat. Using semiquantitative and competitive RT-PCR, we found 5- to 6-fold induction of TNF-alpha mRNA and 3-fold induction of IFN-gamma mRNA in the spinal cord that occurred within 1 h after i.v. injection of Ag and was accompanied by a 2-fold increase of iNOS mRNA. Both IFN-gamma and iNOS mRNA remained elevated for at least 6 h, whereas TNF-alpha mRNA was already down-regulated 6 h after Ag injection. A comparable time course was found for circulating serum levels of TNF-alpha and IFN-gamma. IL-10 mRNA levels did not change significantly following Ag injection. Neutralization of TNF-alpha by anti-TNF-alpha antiserum in vivo led to a significant decrease in the rate of T cell and oligodendrocyte apoptosis induced by high-dose Ag administration, but did not change the beneficial clinical effect of Ag therapy. Our data suggest profound activation of proinflammatory but not of anti-inflammatory cytokine gene expression by high-dose Ag injection. Functionally, TNF-alpha contributes to increased apoptosis of both autoaggressive T cells and oligodendrocytes in the target organ and may thereby play a dual role in this model of Ag-specific therapy of CNS autoimmune diseases.
Weishaupt
A
A
Department of Neurology, Neuroimmunology Branch and Clinical Research Group for Multiple Sclerosis, Julius-Maximilians Universität, Würzburg, Germany.
Jander
S
S
Brück
W
W
Kuhlmann
T
T
Stienekemeier
M
M
Hartung
T
T
Toyka
K V
KV
Stoll
G
G
Gold
R
R
D000818:Animals; D017209:Apoptosis / Q000276:immunology; D001324:Autoantigens / Q000008:administration & dosage / Q000627:therapeutic use*; D002465:Cell Movement / Q000276:immunology; D016207:Cytokines / Q000096:biosynthesis* / Q000097:blood; D018450:Disease Progression; D004306:Dose-Response Relationship, Immunologic; D004334:Drug Administration Schedule; D004681:Encephalomyelitis, Autoimmune, Experimental / Q000201:enzymology / Q000276:immunology* / Q000473:pathology / Q000628:therapy*; D004790:Enzyme Induction / Q000235:genetics / Q000276:immunology; D005260:Female; D005786:Gene Expression Regulation / Q000276:immunology; D006168:Guinea Pigs; D007106:Immune Sera / Q000008:administration & dosage; D007275:Injections, Intravenous; D004676:Myelin Basic Protein / Q000008:administration & dosage / Q000276:immunology* / Q000627:therapeutic use*; D019001:Nitric Oxide Synthase / Q000096:biosynthesis* / Q000235:genetics; D052247:Nitric Oxide Synthase Type II; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D011917:Rats, Inbred Lew; D013116:Spinal Cord / Q000201:enzymology / Q000276:immunology / Q000473:pathology; D018417:Th1 Cells / Q000276:immunology / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology
D001324:Autoantigens; D016207:Cytokines; D007106:Immune Sera; D004676:Myelin Basic Protein; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat