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Antigen presentation and T cell development in H2-M-deficient mice
W P Fung-Leung1, C D Surh, M Liljedahl
1R. W. Johnson Pharmaceutical Research Institute, San Diego, CA 92121, USA.
Science (New York, N.Y.)
|March 1, 1996
Summary
Mice lacking H2-M, the mouse equivalent of HLA-DM, show impaired T cell responses. This highlights the critical role of H2-M in antigen presentation and T cell activation for immune health.
Area of Science:
- Immunology
- Molecular Biology
- Cell Biology
Background:
- Major histocompatibility complex (MHC) class II molecules present peptides to CD4+ T cells.
- HLA-DM (DM) is crucial for efficient peptide loading onto MHC class II molecules in humans.
- H2-M is the murine homolog of human HLA-DM.
Purpose of the Study:
- To investigate the function of H2-M in T cell selection and activation in mice.
- To determine the impact of H2-M deficiency on antigen presentation by antigen-presenting cells (APCs).
Main Methods:
- Analysis of MHC class II expression and peptide loading in H2-M-deficient mice.
- Assessment of CD4+ T cell populations and their responses in H2-M-deficient and wild-type settings.
- Functional assays using H2-M-deficient and wild-type APCs.
Main Results:
- Mice lacking H2-M exhibit normal cell surface MHC class II but with increased association of CLIP peptides.
- H2-M-deficient mice possess expanded CD4+ T cell populations, suggesting thymic positive selection.
- CD4+ T cells from H2-M-deficient mice are unresponsive to H2-M-deficient APCs but hyperreactive to wild-type APCs.
- H2-M-deficient APCs fail to stimulate proliferative responses in wild-type T cells.
Conclusions:
- H2-M is essential for proper peptide editing and presentation by MHC class II molecules.
- H2-M deficiency leads to altered T cell repertoire development and impaired T cell activation.
- These findings underscore the critical role of H2-M in adaptive immunity and immune tolerance.