Measuring oxidation within LC3-associated phagosomes that optimizes MHC class II restricted antigen presentation

Area of Science:

• Immunology
• Cell Biology

Background:

• LC3-associated phagocytosis (LAP) is crucial for antigen presentation via MHC class II molecules.
• LAP involves macroautophagy machinery and forms LC3B-decorated LAPosomes.
• Reactive Oxygen Species (ROS) are known regulators of LAPosome formation and function.

Purpose of the Study:

• To develop and validate methods for monitoring oxidation within LAPosomes.
• To investigate the functional role of oxidation in MHC class II restricted antigen presentation during LAP.

Main Methods:

• Developed two complementary methods to monitor oxidation in LAPosomes in primary human macrophages.
• Method I: Used OxyBURST-coated zymosan to assess LAPosome oxidation via confocal microscopy.
• Method II: Co-cultured macrophages with CD4+ T cells to measure IL-17A and IFN-γ secretion, assessing antigen presentation.

Main Results:

• Presented novel methods for quantifying LAPosome oxidation.
• Demonstrated the utility of these methods in studying the impact of oxidation on antigen presentation.
• Provided insights into the molecular mechanisms regulating LAP and its role in immune responses.

Conclusions:

• Established new tools for studying oxidation in LAP.
• Highlighted the importance of oxidation in modulating antigen presentation by macrophages.
• Advanced the understanding of LAPosome function in MHC class II restricted antigen presentation.