Advanced optical imaging reveals hidden activity in blood immune cells
A routine blood sample contains a diverse collection of immune cells that can reveal important clues about health and disease. These cells, known as peripheral blood mononuclear cells (PBMCs), are widely used to study infections, autoimmune disorders, cancer and the immune system's response to treatment. Scientists typically identify these cells using fluorescent labels that attach to specific…
This study published in Biophotonics Discovery demonstrates how advanced optical imaging can reveal previously hidden metabolic activity within individual immune cells in blood samples. Peripheral blood mononuclear cells (PBMCs) play a crucial role in understanding infections, autoimmune disorders, cancer, and treatment responses.
Traditionally, assessing immune-cell metabolism required isolating specific populations or adding chemical probes, which could alter the cells or miss cellular interactions. The new research introduces optical metabolic imaging (OMI), a nondestructive technique that measures metabolism in individual immune cells without changing their state or requiring external labels.
By using two-photon microscopy to excite natural metabolic cofactors within cells and analyze fluorescence lifetimes, OMI provides insights into cellular activity and activation state. Researchers applied OMI to PBMC samples from three healthy donors, analyzing thousands of cells in both resting and activated states. Machine learning algorithms identified key differences between cell populations, distinguishing activated PBMCs from resting ones with 94% accuracy and accurately identifying monocytes, natural killer (NK) cells, and other immune cells.
The study found significant metabolic differences among immune-cell types, with monocytes and NK cells displaying distinct signatures. This information could offer valuable insights into disease progression and treatment response. Importantly, OMI preserves cell viability, making it ideal for cell therapy applications such as CAR T-cell treatments.
The technique's ability to measure single-cell metabolism without altering samples complements existing methods and could provide a more detailed picture of immune system function, particularly in heterogeneous cell populations. While still primarily a research tool, OMI holds promise for clinical applications in evaluating cellular fitness for cell therapies, highlighting the potential of optical imaging to enhance our understanding of immune system dynamics.
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