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Telomere Length and Telomerase Activity; A Yin and Yang of Cell Senescence
Published on: May 22, 2013
Quantum dots thermal stability improves simultaneous phenotype-specific telomere length measurement by FISH-flow
Veena Kapoor1, Fran T Hakim, Najibah Rehman
1Experimental Transplantation and Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA. veenak@helix.nih.gov
Journal of Immunological Methods
|March 10, 2009
Summary
Quantum dots enhance fluorescence in situ hybridization flow cytometry (FISH-flow) for simultaneous telomere length analysis and immunophenotyping. This method allows precise measurement of telomere length in specific cell subsets without prior cell sorting.
Area of Science:
- Cell Biology
- Biotechnology
- Immunology
Background:
- Quantitative flow cytometry technique FISH-flow simplifies telomere length analysis.
- Traditional FISH-flow uses fluorescent probes with limited thermal stability, hindering simultaneous immunolabeling.
- High annealing temperatures (82°C) degrade standard fluorophores, complicating analysis of complex cell populations.
Purpose of the Study:
- To develop a method for simultaneous immunophenotyping and telomere length measurement using FISH-flow.
- To overcome the thermal instability limitations of traditional fluorescent probes in FISH-flow.
- To enable high-throughput, single-cell analysis of telomere length in specific immune cell subsets.
Main Methods:
- Substituted traditional fluorophores with quantum dots (nanoparticles) in the FISH-flow technique.
- Utilized quantum dot antibody conjugates for monocyte and T cell antigens.
- Performed simultaneous FISH-flow and immunophenotyping with multiple quantum dot conjugates (Qdot 605, 655, 705).
Main Results:
- Quantum dots exhibited greater thermal stability than conventional fluorophores.
- Quantum dot conjugates retained fluorescence after high-temperature annealing, enabling combined analysis.
- Successfully measured age-associated telomere length decline in human monocytes and T cell subsets.
- Calculated a mean telomere length decrease rate of 41.8 bp/year for CD4+ cells.
Conclusions:
- Quantum dot-based FISH-flow allows simultaneous immunophenotyping and telomere length measurement.
- This modified technique enables complex cell subset-specific analysis without prior cell sorting.
- The method is suitable for analyzing small cell numbers and assessing telomere dynamics in immune aging.
