Studies in B7-deficient mice reveal a critical role for B7 costimulation in both induction and effector phases of experimental autoimmune encephalomyelitis.
The importance of B7 costimulation in regulating T cell expansion and peripheral tolerance suggests that it may also play a significant regulatory role in the development of autoimmune disease. It is unclear whether B7 costimulation is involved only in the expansion of autoreactive T cells in the periphery, or if it is also required for effector activation of autoreactive T cells in the target organ for mediating tissue injury and propagating autoimmune disease. In this study, the role of B7-CD28 costimulation and the relative importance of B7 costimulators for the induction and effector phases of experimental autoimmune encephalomyelitis (EAE) induced by myelin oligodendrocyte glycoprotein (MOG) peptide were examined. Wild-type, B7-1/B7-2-deficient mice, or CD28-deficient C57BL/6 mice were immunized with MOG 35-55 peptide. Mice lacking both B7-1 and B7-2 or CD28 showed no or minimal clinical signs of EAE and markedly reduced inflammatory infiltrates in the brain and spinal cord. However, mice lacking either B7-1 or B7-2 alone developed clinical and pathologic EAE that was comparable to EAE in wild-type mice, indicating overlapping functions for B7-1 and B7-2. Resistance to EAE was not due to a lack of induction of T helper type 1 (Th1) cytokines, since T cells from B7-1/B7-2(-/-) mice show reduced proliferative responses, but greater interferon gamma production compared with T cells from wild-type mice. To study the role of B7 molecules in the effector phase of the disease, MOG 35-55-specific T lines were adoptively transferred into the B7-1/B7-2(-/-) and wild-type mice. Clinical and histologic EAE were markedly reduced in B7-1/B7-2(-/-) compared with wild-type recipient mice. These results demonstrate that B7 costimulation has critical roles not only in the initial activation and expansion of MOG-reactive T cells, but also in the effector phase of encephalitogenic T cell activation within the central nervous system.
Chang
T T
TT
Immunology Research Division, Department of Pathology, Center for Neurologic Diseases, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA.
Jabs
C
C
Sobel
R A
RA
Kuchroo
V K
VK
Sharpe
A H
AH
D019264:Adoptive Transfer; D000595:Amino Acid Sequence; D000818:Animals; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism*; D018122:B7-1 Antigen / Q000235:genetics / Q000378:metabolism*; D051940:B7-2 Antigen; D018106:CD28 Antigens / Q000235:genetics / Q000378:metabolism; D004681:Encephalomyelitis, Autoimmune, Experimental / Q000209:etiology* / Q000276:immunology / Q000473:pathology; D005260:Female; D008213:Lymphocyte Activation; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008969:Molecular Sequence Data; D009185:Myelin Proteins; D018992:Myelin-Associated Glycoprotein / Q000235:genetics / Q000276:immunology; D063308:Myelin-Oligodendrocyte Glycoprotein; D010446:Peptide Fragments / Q000235:genetics / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology; D014611:Vaccination
D015703:Antigens, CD; D018122:B7-1 Antigen; D051940:B7-2 Antigen; D018106:CD28 Antigens; C497965:Cd86 protein, mouse; D008562:Membrane Glycoproteins; C571327:Mog protein, mouse; D009185:Myelin Proteins; D018992:Myelin-Associated Glycoprotein; D063308:Myelin-Oligodendrocyte Glycoprotein; D010446:Peptide Fragments