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Presentation of autoantigen by human T cells
J M LaSalle1, K Ota, D A Hafler
1Department of Medicine, Brigham and Women's Hospital, Boston, MA.
Journal of Immunology (Baltimore, Md. : 1950)
|August 1, 1991
Summary
Activated T cells can present myelin basic protein (MBP) peptide antigens to other T cells, independent of traditional antigen-presenting cells. This T-cell mediated antigen presentation suggests a role in regulating immune responses to self-antigens in vivo.
Area of Science:
- Immunology
- Cell Biology
- Autoimmunity
Background:
- Activated T cells express MHC class II molecules.
- T cells are known to present foreign antigens to autologous T cells.
Purpose of the Study:
- To investigate if T cell clones can present autoantigens to other T cells.
- To explore the mechanism and implications of T cell-mediated antigen presentation in autoimmunity.
Main Methods:
- Utilized MHC class II-positive T cell clones to present myelin basic protein (MBP) peptide autoantigen.
- Assessed T cell activation via calcium flux and proliferation assays.
- Investigated the role of adhesion molecules and MHC class II in T-cell interactions using monoclonal antibodies (mAbs).
Main Results:
- MHC class II-positive T cell clones presented MBP peptide autoantigen to autologous MBP-reactive T cell clones.
- Presentation was peptide epitope-specific, TCR-mediated, and blocked by anti-MHC class II mAbs.
- T cell proliferation was inhibited by mAbs against adhesion molecules (LFA-3, CD2, LFA-1, CD29) and CD45, indicating T-T cell interactions.
- T cells could not process whole MBP but presented naturally occurring breakdown products.
Conclusions:
- Activated T cells can present autoantigen breakdown products in the absence of traditional antigen-presenting cells.
- T cell-mediated antigen presentation may play a role in regulating immune responses to self-antigens at inflammatory sites.