The Cell Isolation and Analysis Core (Core B) will consist of two components, flow cytometry and histology, and will provide technical and advisory support for all three Projects. The Core will aid investigators in experimental design for cell isolation and in analysis of flow cytometry data from murine, non-human primate and human samples. Core B will be administered by Dr. Crooks at CHLA, and Dr. Linda Baum at UCLA (Co-Director). FACS analysis and sorting and preparation of tissue sections will occur at CHLA and interpretation of specific tissue samples will be performed by Dr Baum at UCLA. At CHLA, FACSVantage, FACSAria, FACSCalibur and FACScan flow cytometry machines will be available for cell isolation and analysis The histology component will also be housed at CHLA, and will support Projects 1 and 3 by preparing whole mounts and tissue sections by cryostat and microtome, and performing staining with standard or immunofluorescent techniques.