Related Experiment Video
Updated: Aug 8, 2026
07:05
Fluorescence-mediated Tomography for the Detection and Quantification of Macrophage-related Murine Intestinal Inflammation
Published on: December 15, 2017
Two-photon fluorescence lifetime imaging microscopy of macrophage-mediated antigen processing
1Department of Physics, University of Illinois at Urbana-Champaign 61801, USA.
Journal of Microscopy
|March 1, 1997
Summary
This study used two-photon fluorescence lifetime imaging microscopy to track antigen processing in macrophages. It revealed time-dependent changes in fluorescence reflecting protease activity during endocytosis and degradation.
Area of Science:
- Cell Biology
- Immunology
- Biophysics
Background:
- Macrophage-mediated endocytosis is crucial for immune responses.
- Intracellular antigen processing involves complex biochemical events.
- Noninvasive monitoring of these processes is essential for understanding cellular mechanisms.
Purpose of the Study:
- To noninvasively monitor antigen processing within macrophages using advanced microscopy.
- To investigate the role of proteases in antigen degradation.
- To correlate fluorescence changes with specific intracellular events.
Main Methods:
- Utilized two-photon fluorescence lifetime imaging microscopy (2p-FLIM).
- Employed fluorescein-conjugated bovine serum albumin (FITC-BSA) as a model antigen.
- Conducted control experiments with fluorescein-conjugated poly-L-lysine and poly-D-lysine.
Main Results:
- Observed a significant increase in fluorescein fluorescence lifetime from 0.5 ns to 3.0 ns during antigen processing.
- Demonstrated that proteolysis is responsible for the observed fluorescence changes, as shown by inert D-isomer controls.
- Indicated active macrophage localization of FITC-dextran within vacuoles.
- Validated 2p-FLIM findings against flow cytometry data for antigen degradation kinetics.
Conclusions:
- Two-photon fluorescence lifetime imaging microscopy is a powerful tool for real-time monitoring of intracellular antigen processing.
- Protease activity is a key determinant of antigen processing and fluorescence changes within macrophages.
- The study validates flow cytometry as a reliable method for future antigen processing studies.
