C. Viret et Ca. Janeway, Functional and phenotypic evidence for presentation of E alpha(52-68) structurally related self-peptide(s) in I-E alpha-deficient mice, J IMMUNOL, 164(9), 2000, pp. 4627-4634
The Y-Ae mAb and the 1H3.1 TCR-alpha beta (V alpha 1/V beta 6) are two immu
ne receptors specific for I-A(b) MHC class II molecules complexed to the 52
-68 fragment of the alpha-chain of I-E class II molecules (the E alpha(52-6
8) peptide). A profound intrathymic negative selection occurs in 1H3.1 TCR
transgenic mice in the presence of an I-E alpha transgene. The administrati
on of mAbs to 1H3.1/I-E alpha double-transgenic newborn mice reveals that Y
-Ae, but not the isotype-matched anti-I-E Y17 mAb, rescues a significant nu
mber of mature (V beta 6(high)CD4(+)CD8(-)) thymocytes and allows the detec
tion of E alpha(52-68)-reactive T cells in the periphery. These observation
s indicate that deletion of autoreactive T cells can be specifically inhibi
ted in vivo by an mAb specific for the deleting self-peptide:self-MHC class
II complex. Similar inhibition experiments indicate that C57BL/6 (I-A(b)/I
-E alpha(-)) mice constitutively express an E alpha-independent, Y-Ae-recog
nizable epitope(s). This finding is confirmed by the phenotypic analysis of
mature (MHC class II high) C57BL/6 bone marrow-derived dendritic cells. Co
llectively, these observations further illustrate the peptide specificity o
f negative selection and demonstrate that MHC class II-positive cells from
unmanipulated C57BL/6 mice that lack a functional I-E alpha gene can assemb
le one or more self-peptide:I-A(b) complexes recognizable by the E alpha(52
-68):I-A(b) complex-specific Y-Ae mAb.