Targeted regulation of self-peptide presentation prevents type I diabetes in mice without disrupting general immunocompetence
Woelsung Yi, Nilufer P. Seth, Tom Martillotti, Kai W. Wucherpfennig, Derek B. Sant’Angelo, Lisa K. Denzin
Woelsung Yi, Nilufer P. Seth, Tom Martillotti, Kai W. Wucherpfennig, Derek B. Sant’Angelo, Lisa K. Denzin
View: Text | PDF
Research Article Immunology

Targeted regulation of self-peptide presentation prevents type I diabetes in mice without disrupting general immunocompetence

Abstract

Peptide loading of MHC class II (MHCII) molecules is directly catalyzed by the MHCII-like molecule HLA-DM (DM). Another MHCII-like molecule, HLA-DO (DO), associates with DM, thereby modulating DM function. The biological role of DO-mediated regulation of DM activity in vivo remains unknown; however, it has been postulated that DO expression dampens presentation of self antigens, thereby preventing inappropriate T cell activation that ultimately leads to autoimmunity. To test the idea that DO modulation of the MHCII self-peptide repertoire mediates self tolerance, we generated NOD mice that constitutively overexpressed DO in DCs (referred to herein as NOD.DO mice). NOD mice are a mouse model for type 1 diabetes, an autoimmune disease mediated by the destruction of insulin-secreting pancreatic β cells. Our studies showed that diabetes development was completely blocked in NOD.DO mice. Similar to NOD mice, NOD.DO animals selected a diabetogenic T cell repertoire, and the numbers and function of Tregs were normal. Indeed, immune system function in NOD.DO mice was equivalent to that in NOD mice. NOD.DO DCs, however, presented an altered MHCII-bound self-peptide repertoire, thereby preventing the activation of diabetogenic T cells and subsequent diabetes development. These studies show that DO expression can shape the overall MHCII self-peptide repertoire to promote T cell tolerance.

Authors

Woelsung Yi, Nilufer P. Seth, Tom Martillotti, Kai W. Wucherpfennig, Derek B. Sant’Angelo, Lisa K. Denzin

×

Figure 8

I-Ag7 molecules in NOD.DO DCs have reduced levels of SDS-stable dimers.

Options: View larger image (or click on image) Download as PowerPoint
I-Ag7 molecules in NOD.DO DCs have reduced levels of SDS-stable dimers. ...
(A) Titrated amounts of detergent lysates (20, 6.67, and 2.22 × 104 cell equivalents/lane) from purified NOD and NOD.DO splenic DCs were separated by SDS-PAGE, transferred to membranes, and probed with a rabbit sera specific for the cytoplasmic tail of I-Aβ. To demonstrate proportional loading, the blot was also probed with a mAb specific for actin. Data are representative of 3 independent experiments. (B) Detergent lysates from purified splenic DCs (2.5 × 105 cell equivalents/lane) or B cells (5 × 105 cell equivalents/lane) were incubated in sample buffer at room temperature (nonboiled; NB) or boiled (B) prior to separation by SDS-PAGE and transfer to membrane. Blots were probed with a polyclonal rabbit anti-sera to the cytoplasmic tail of I-Aβ. Probing of the blot with a mAb specific for GAPDH demonstrated equal loading. B6 DCs are included as a positive control for MHCII peptide complex formation (αβpep). Data are representative of 4 (DCs) and 3 (B cells) independent experiments. (C) Quantification of the level of I-Ag7 SDS-stable dimers in NOD.DO DCs or B cells relative to NOD DCs or B cells, respectively. Each symbol represents an individual experiment and small horizontal bar indicates the mean.