The goal of this program project is the development of new methodologies appropriate for applications of flow cytometry in cell biology and medicine. The core facility (Project A) will provide multiparameter cell sorters, associated instrumentation, and professional and technical support for a multiuser facility. The core facility will also be responsible for development of new instrumental capabilities and data analysis techniques required by individual research projects. The goals of the seven research projects included in this program are summarized below: Project B (Fetal Genetics): Develop new methodologies for detection of rare events (fetal cells in maternal circulation) and for multiparameter analyses of amniotic cells (fetal maturation or abnormalities). Project C (Cytochemistry): Develop methodologies for differential staining of stimulated and nonstimulated cell populations using fluorescent membrane potential sensitive dyes. Project D (Antigen Binding): Continue characterization of antigen-binding B lymphocytes and develop new methods for detection of antigen-binding T lymphocytes. Project E (Cancer Chemotherapy): Develop methodologies for characterization of tumor cell subpopulations and attempt to identify parameters which predict and/or reflect drug toxicity. Project F (Somatic Cell Genetics): Develop methodologies for analysis, ultra-sterile sorting and recovery of small numbers of mutant cells to allow further genetic analysis. Project G (Microspheres): Develop methodologies for quantitation of antinuclear antibodies in human serum directed against particular nuclear components. Project H (Viral Binding Receptors): Develop methodologies which can be used to characterize interactions between adenoviruses and human cells.