Abstract: Disclosed are improved methods for manufacturing large-scale populations of robust, highly pure, and functional T regulatory cells (Tregs). Also disclosed are expanded Treg populations, cryopreserved Treg populations and methods and uses of these cells in compositions formulated for treating one or more mammalian diseases, including, for example, treatment, prophylaxis, and/or amelioration of one or more symptoms of a human neurodegenerative disorder. In particular, the compositions and methods provided herein find clinical use in the treatment and amelioration of one or more symptoms of amyotrophic lateral sclerosis (ALS), Alzheimer's disease, and other neurological diseases and disorders.