These cells are also rare events in the blood and so may be identified in a similar way to dendritic cells by excluding unwanted cells from the analysis. So for example by excluding all cells that are CD2, CD19 and CD33 positive this will allow analysis of non committed cells. The addition of antibodies to stem cells (CD133) or specific progenitor phenotypes (VEGF-R) will then allow identification of specific progenitor cells. e.g.immunophenotyping stem cells in Head and Neck Squamous cell carcinoma cell line, CaLH2.
Side population analysis
The ability of stem cells to pump substrates at faster rate than normal via MDR1 and/or ATP Binding Cassettes, (ABCG2 regions) allows the identification of a side population (SP) of stem cells when cells are loaded with Hoechst 33342 and stained with PI.
Excitation of Vybrant DyeCycle Violet with 405nm violet laser allows SP sorting on a BD Aria I, see figure.
Excitation of Hoechst 33342 with UV lasers at >50mW on jet in air instrument systems or lower at <25mW on cuvette systems can allow sorting and analysis of SP cells.
Excitation of Hoechst 33342 with a 405 nm Violet Diode on cuvette instrument systems can allow sorting and analysis of SP cells.