Autofluorescence lifetime imaging classifies human B and NK cell activation state

Area of Science:

• Immunology
• Cell Biology
• Biophysics

Background:

• Non-destructive, single-cell resolution tools are crucial for evaluating B cell and NK cell function.
• Applications include adoptive cell therapy and immune profiling.
• Optical metabolic imaging (OMI) is a label-free technique quantifying single-cell metabolism via autofluorescence of NAD(P)H and FAD.

Purpose of the Study:

• To demonstrate OMI's capability in resolving metabolic differences between quiescent and activated primary human B and NK cells.
• To assess the potential of OMI for label-free, non-destructive evaluation of immune cell activation status.

Main Methods:

• Utilized Optical Metabolic Imaging (OMI) to measure autofluorescence intensity and lifetime of NAD(P)H and FAD in single cells.
• Compared metabolic profiles of quiescent versus activated (IL-4/anti-CD40 for B cells; IL-12/IL-15/IL-18 for NK cells) primary human cells.
• Employed random forest models to classify cell activation states based on OMI-derived metabolic parameters.

Main Results:

• Stimulated B and NK cells exhibited altered metabolism, including increased free NAD(P)H, reduced redox state, and elevated lactate production.
• A decrease in NAD(P)H mean fluorescence lifetime was observed in activated B and NK cells.
• Random forest models achieved 93% accuracy in classifying B and NK cell activation states using OMI data.

Conclusions:

• Autofluorescence lifetime imaging via OMI can accurately assess B and NK cell activation.
• OMI provides a label-free and non-destructive method for immune cell functional analysis.
• This approach holds promise for applications in adoptive cell therapy and immune profiling.