*3.3. Isolation and Culture of Human CD4*<sup>+</sup> *Naïve Th (Th0) Cells*

This study was approved by the Institutional Review Board of Pusan National University (H-1802-006-063). MNCs were isolated from human cord blood provided by Busan/Ulsan/Gyeongnam Cord Blood Bank using HetaSep (Stem Cell Technologies, British Columbia, Canada) and Lymphoprep (Stem Cell Technologies) as per the manufacturer's instructions. Total naive Th0 cells were then purified by negative selection with magnetic beads provided in the Human Naive CD4<sup>+</sup> T Cell Isolation Kit II (Miltenyi Biotec, Bergisch Gladbach, Germany). Purified cells were determined for their purity (more than 95% CD4<sup>+</sup> cells) and then plated in the density of 1 <sup>×</sup> 106 cells/well in a 12-well culture plate and cultured in expansion media consisting of the ImmunoCult-XF T Cell Expansion Medium (Stem Cell Technologies), ImmunoCult Human CD3/CD28/CD2 T Cell Activator (Stem Cell Technologies) and IL-2 (Peprotech, Rocky Hill, NJ, USA).
