The invention provides a method of treating T-cell mediated diseases and a method of inhibiting the activation of T-cells using certain diketopiperazines. The amino acid lipid compounds and compositions can be used for delivery of various agents such as nucleic acid therapeutics to cells, tissues, organs, and subjects. The drain is split between a n drain and a floating n region near the gate to avoid excessive avalanche injection and resultant local overheating. The stopper portion is cold formed under a compressive load exceeding the compressive load required to deform the sealing beads beyond their elastic limit, thereby preventing irreversible damage to the sealing beads. The latter process in particular enables full or partial automation of the winding andor assembly process.