Internalization

Cellular processes such as drug uptake and processing by cells, entry of pathogens and toxins, or antigen processing and presentation are studied on the ImageStream by measuring internalization.  The ImageStream system automatically collects large numbers of images per data set and provides quantitative image analysis tools that facilitates the objective and rapid localization of internalized probes. Because the ImageStream collects multiple fluorescent images per cell, internalized markers in phenotypically distinct sub-populations as well as colocalization to different cellular compartments (see co-localization) can be simultaneously determened in a quantitative manner.

Phagocytosis by murine macrophages

Internalization of zymosan (green) by murine RAW cells (orange) identified by immunophenotyping. Phagocytosis is measured as the percentage of cells with internalized zymosan at 15, 30 and 60 minutes at 37 degrees C.

Internalization of CpGB in primary plasmacytoid dendritic cells

Binding, internalization, and colocalization to of CpGB (red) to lysosomes (green) by plasmacytoid dendritic cells (pDC, orange) is measured using the ImageStream. This data highlights a couple strengths of the ImageStream: 1) combination of immunophenotyping (pDC identification via fluorescent intensity staining) with image correlation and internalization analysis, allowing measurement of co-localization and internalization of molecules within specific subsets. 2) ability to measure these events in small, primary cells with small cytoplasmic compartments. See application note for more details.