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12:48
Purification of the Membrane Compartment for Endoplasmic Reticulum-associated Degradation of Exogenous Antigens in Cross-presentation
Published on: August 21, 2017
Class II MHC molecules are spontaneously internalized in acidic endosomes by activated B cells
D A Weber1, L B Buck, T M Delohery
1Department of Microbiology, College of Physicians and Surgeons, Columbia University, New York, NY 10032.
The Journal of Molecular and Cellular Immunology : JMCI
|January 1, 1990
Summary
B cells internalize Class II MHC molecules to endosomes, where they meet processed antigens. This endocytic pathway is crucial for B cells to present antigens to helper T cells.
Area of Science:
- Immunology
- Cell Biology
- Molecular Biology
Background:
- Antibody response requires B and T cell cooperation.
- T cells need processed antigens presented by B cells via Class II MHC molecules.
Purpose of the Study:
- To determine where Class II MHC and processed antigens complex within B cells.
- To investigate the intracellular trafficking of Class II MHC molecules.
Main Methods:
- Two-color immunofluorescence microscopy in LPS-activated murine B cells.
- Flow cytometry using fluoresceinated antibodies to track molecule internalization.
Main Results:
- Class II MHC molecules extensively co-localized with immunoglobulin ligands in endosomes.
- Quantitative data supported the endocytosis of Class II MHC molecules by B cells.
- Activated B cells endocytose membrane Class II MHC, but not Class I MHC.
Conclusions:
- Class II MHC molecules primarily reach endosomes via endocytosis in activated B cells.
- This pathway facilitates antigen presentation to Class II-restricted helper T cells.
- Findings clarify antigen handling by B cells for T cell activation.
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