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Phagocytic processing of antigens for presentation by class II major histocompatibility complex molecules
L Ramachandra1, E Noss, W H Boom
1Institute of Pathology, Case Western Reserve University, Cleveland, OH 44106-4943, USA.
Cellular Microbiology
|February 24, 2001
Summary
Phagosomes can process antigens and form peptide-MHC-II complexes for T cell presentation. Pathogenic microbes can disrupt this process, hindering antigen presentation.
Area of Science:
- Immunology
- Cell Biology
- Antigen Processing
Background:
- Phagocytosis is key for internalizing antigens (Ags) into phagosomes.
- The precise location of peptide-MHC-II complex formation within phagosomes or endosomes was unclear.
Purpose of the Study:
- To investigate whether peptide-MHC-II complexes form within phagosomes.
- To understand the role of phagosomes in antigen presentation.
Main Methods:
- Utilized phagosomes containing antigen-conjugated latex beads.
- Analyzed the presence of antigen-processing molecules (MHC-II, invariant chain, H2-DM, proteases) within phagosomes.
- Tracked the acquisition of MHC-II molecules and formation of peptide-MHC-II complexes.
Main Results:
- Phagosomes with bead-associated Ags contain necessary processing machinery.
- Peptide-MHC-II complex formation occurs within phagosomes.
- Newly synthesized MHC-II molecules are primarily involved in complex formation.
- Pathogenic microbes like Mycobacterium tuberculosis can impair phagosome function and antigen presentation.
Conclusions:
- Phagosomes are active sites for antigen processing and peptide-MHC-II complex formation.
- Newly synthesized MHC-II molecules are crucial for this process within phagosomes.
- Pathogens can evade immune detection by manipulating phagosome function.