Systemic administration of agonist peptide blocks the progression of spontaneous CD8-mediated autoimmune diabetes in transgenic mice without bystander damage
N. Bercovici et al., Systemic administration of agonist peptide blocks the progression of spontaneous CD8-mediated autoimmune diabetes in transgenic mice without bystander damage, J IMMUNOL, 165(1), 2000, pp. 202-210
Insulin-dependent diabetes is an autoimmune disease targeting pancreatic be
ta-islet cells. Recent data suggest that autoreactive CD8(+) T cells are in
volved in both the early events leading to insulitis and the late destructi
ve phase resulting in diabetes. Although therapeutic injection of protein a
nd synthetic peptides corresponding to CD4(+) T cell epitopes has been show
n to prevent or block autoimmune disease in several models, down-regulation
of an ongoing CD8(+) T cell-mediated autoimmune response using this approa
ch has not yet been reported. Using CL4-TCR single transgenic mice, in whic
h most CD8(+) T cells express a TCR specific for the influenza virus hemagg
lutinin HA(512-520) peptide:K-d complex, we first show that i.v. injection
of soluble HA(512-520) peptide induces transient activation followed by apo
ptosis of Tc1-like CD8(+) T cells. We next tested a similar tolerance induc
tion strategy in (CL4-TCR x Ins-HA)F-1 double transgenic mice that also exp
ress HA in the beta-islet cells and, as a result, spontaneously develop a j
uvenile onset and lethal diabetes. Soluble HA(512-520) peptide treatment, a
t a time when pathogenic CD8(+) T cells have already infiltrated the pancre
as, very significantly prolongs survival of the double transgenic pups, In
addition, we found that Ag administration eliminates CD8(+) T cell infiltra
tes from the pancreas without histological evidence of bystander damage. Ou
r data indicate that agonist peptide can down-regulate an autoimmune reacti
on mediated by CD8(+) T cells in vivo and block disease progression. Thus,
in addition to autoreactive CD4(+) T cells, CD8(+) T cells may constitute t
argets for Ag-specific therapy in autoimmune diseases.