This critically important core provides routine and consistent analysis of spleen cells, cervical lymph node cells, PBL and inflammatory cells derived from the CNS. As noted in the individual projects, critical analysis of the cells infiltrating the CNS during infection, as well as the resident CNS cells (oligodendroglia, astrocytes and microglia) are important components of the overall program. Differential expression of surface markers for precise determination of the cell types infiltrating the CNS, thru activation state and the identity of CNS resident cells are all critical to the proposed projects. Flow cytometry is superior to immunohistochemistry in that cell types can be distinguished by intensity of fluorescence as well as by multiple surface or intracellular markers. The best example is the separation of microglia from infiltrating perivascular macrophages via their differential intensity of CD45 staining. This distinction cannot be made by histological examination. Analysis of resident CNS cell types cannot be made by histological examination. Analysis of resident CNS cell types for expression of MHC and co-stimulatory molecules thus promises to be highly sensitive. Furthermore, purified populations to be obtained by sorting, require a critical evaluation of their precise identity. All of these functions are carried out by this core. Both the core technician and the core director have been trained by BD in the operation of the FACS Calibur flow cytometer equipped with 2 lasers for 4-color analysis.
