Characterizing Cells

What To Characterize Confirmation Of Species Of Origin Correlation With The Tissue Of Origin Transformation Status Finite Or Continuous Cross-Contamination Stability (ex. susceptibility to transformation)

Species Identification –Chromosomal analysis Tissue Markers –Cell surface markers Ex. CD11c if DC –Intermediate filament proteins Ex. 1 Glial fibrillary acidic protein (GFAP) for astrocytes. Ex. 2 Desmin for muscle cells. Ex. 3 Cytokeratin for epithelial cells –Differentiated products Ex. Melanin for melanocytes, hemoglogin for erythroid cells, serum albumin for hepatocytes –Unique Markers Ex. HLA highly polymorphic, unique to an individual Morphology –Easy and fast but has variability depending on culturing conditions and site How Is Characterization Done

Allows For Detection Of Surface Markers Of Cells Allows For Detection Of Intracellular Factors Allows Detection Of Secreted Factors By Cells Allows For Detection Of DNA Content Flow Cytometry Is A Powerful Technique For Characterizing Cells

Principles Of Flow Cytometry

How Is It Done:

Some Information Can Be Obtained FSC Correlates With Cell Size SSC Correlates With Internal Complexity To Distinguish Between 2 Cell types –A. Size Has To Be Different OR –B. Internal Complexity i.e amount of granules If These Two Parameters Are The Same, Then No Distinction Can Be Made See The Following Figure Limitations With Light Scattering

FSC vs SSC Dot Plot

Fluorescence And Antibodies To The Rescue

Fluorochromes Are Molecules That Emit Fluorescence Upon Excitation With Light –Ex. FITC (Fluorescein Isothiocyanate) –PE (Phycoerythrin) –PerCP (Peridinin Chlorophyll Protein) –APC (Allophycocyanin) Some Fluorochromes Are Proteins, Some Are Small Organic Compounds –Ex. PE (Phycoerythrin)-Protein –Ex. FITC (Fluorescein Isothiocyanate) Fluorescent Dyes And Antibodies

Principles Of Fluorescence E= h f  = f

Excitation Spectra Of Fluorochromes

Emission Spectra

Architecture Of A FacsCalibur Instrument

Analyzed Data

20 80 GM-CSF+IL-4+PGE GM-CSF+IL GMF: GMF: GMF: GMF: 1.85 Fig. 2

ISOTYPESUnstained

GM-CSF GM-CSF + IL-4 (6 Days Old)