Abstract: The present invention provides materials and methods for the isolation of immune cells. In one embodiment, the present invention provides a device for the isolation and separation of antigen-specific memory B cells. Immune cells will be separated by flowing the cells along a ligand-conjugated biopolymer surface. The ligand may be distributed in a concentration gradient along the z-axis of the biopolymer surface. Cells that display receptors specific for the ligands on the biopolymer will interact with the ligands and roll along the surface in the fashion of leukocyte rolling. Additive adhesive interactions will cause differential cell separation and eventual immobilization.

Abstract: The present invention relates to novel selection marker vectors, and methods for using these vectors to generate stable gene expression systems in eukaryotic cells utilizing any enzyme useful in the eukaryotic sterol/cholesterol biosynthetic pathway, such as a 3-ketosteroid reductase, as a metabolic selection marker to select transfected cells. In one embodiment, the method comprises transfecting cells that are auxotrophic for cholesterol with a vector encoding 3-ketosteroid reductase and at least one heterologous protein, and selecting cells that have the ability to survive in medium lacking cholesterol and/or producing the heterologous protein in these cells in chemically defined and/or serum-free media.

Abstract: The present invention relates to novel selection marker vectors, and methods for using these vectors to generate stable gene expression systems in eukaryotic cells utilizing any enzyme useful in the eukaryotic sterol/cholesterol biosynthetic pathway, such as a 3-ketosteroid reductase, as a metabolic selection marker to select transfected cells. In one embodiment, the method comprises transfecting cells that are auxotrophic for cholesterol with a vector encoding 3-ketosteroid reductase and at least one heterologous protein, and selecting cells that have the ability to survive in medium lacking cholesterol and/or producing the heterologous protein in these cells in chemically defined and/or serum-free media.