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Invariant chain influences post-translational processing of HLA-DR molecules
W T Schaiff1, K A Hruska, C Bono
1Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110.
Journal of Immunology (Baltimore, Md. : 1950)
|July 15, 1991
Summary
The invariant chain (Ii) significantly impacts human leukocyte antigen (HLA) class II molecule maturation. Ii influences the post-translational processing and glycosylation of HLA-DR alpha- and beta-chains.
Area of Science:
- Immunology
- Molecular Biology
- Cell Biology
Background:
- HLA class II molecules are crucial for immune responses.
- The invariant chain (Ii) is associated with HLA class II synthesis but its role in post-translational processing is not fully understood.
Purpose of the Study:
- To investigate the influence of the invariant chain (Ii) on the post-translational processing and maturation of HLA class II molecules.
- To determine if Ii affects the glycosylation and endo H sensitivity of HLA-DR alpha- and beta-chains.
Main Methods:
- Transfection of BALB/c 3T3 cells with HLA-DR alpha- and beta-chains with or without human Ii.
- Analysis of molecular weight (m.w.) and glycosylation patterns using endo H sensitivity.
- Pulse/chase studies to assess processing rates.
Main Results:
- Ii had no effect on surface expression of HLA-DR.
- Ii significantly altered the post-translational processing of both alpha- and beta-chains.
- In the absence of Ii, chains were of lower m.w., with increased endo H sensitivity, indicating incomplete glycosylation.
Conclusions:
- The invariant chain (Ii) plays a critical role in the post-translational processing of HLA class II molecules.
- Ii affects the proportion of HLA class II chains processed and the extent of oligosaccharide processing on mature chains.