The invention relates to novel artificial antigen presenting cells (aAPCs). The aAPC comprises at least one stimulatory ligand and at least one costimulatory ligand where the ligands each specifically bind with a cognate molecule on a T cell of interest, thereby mediating expansion of the T cell. The aAPC of the invention can further comprise additional molecules useful for expanding a T cell of interest. The aAPC of the invention can be used as an "off the shelf APC that can be readily designed to expand a T cell of interest. Also, the aAPC of the invention can be used identify the stimulatory, costimulatory, and any other factors that mediate growth and expansion of a T cell of interest. Thus, the present invention provides powerful tools for development of novel therapeutics where activation and expansion of a T cell can provide a benefit.
