Eur J Immunol. 2003 Jul;33(7):2022-2032
Chang TT, Sobel RA, Wei T, Ransohoff RM, Kuchroo VK, Sharpe AH.
Immunology Research Division, Department of Pathology, Brigham and
Women's Hospital, Harvard Medical School, 221 Longwood Avenue, Boston,
MA 02115, USA.
Adoptive transfer experiments using C57BL/6 mice lacking B7-1 and B7-2 as recipients of wt (wt) encephalitogenic T cells demonstrate a key role for B7 costimulation during the effector phase of experimental autoimmune encephalomyelitis (EAE).
Following transfer of encephalitogenic T cells, B7-1/B7-2-deficient (-/-) recipients develop a transient and mild disease as compared to wt recipients.
To understand the mechanism by which B7-1/B7-2 may influence the effector phase of EAE, we analyzed T cells, pro-inflammatory cytokines and chemokines within the CNS of wt and B7-1/B7-2-/- recipients at different times after adoptive transfer of activated myelin specific T cells.
There was a marked decline in T cells and inflammatory mediators in the CNS of B7-1/B7-2-/- recipients by day 30 post transfer.
B7-1/B7-2-/- mice developed more TUNEL+ apoptotic cells in the parenchyma and greater ratios of TUNEL+ cells/parenchymal foci than wt mice resulting in virtual disappearance of parenchymal foci.
Therefore, without B7-1 and B7-2 costimulation in the target organ, there is increased T cell apoptosis and attenuation of inflammation.
These results indicate that B7-1 and B7-2 provide critical costimulatory signals for sustaining survival of pathogenic T cells within the central nervous system parenchyma during the effector phase of EAE and suggest novel treatment approaches in the effector phase of autoimmune diseases.