Method for obtaining regulatory T cells derived from thymic tissue and use of said cells as cell immunotherapy in immune system disorders

A cell population comprising regulatory T (Treg) cells obtained from isolated thymic tissue (a thyTreg cell population),

• wherein said thyTreg cell population comprises CD4+CD8 Foxp3+ cells;
• wherein said thyTreg cell population comprises at least 90% of CD4+CD25+Foxp3+ cells;
• wherein said thyTreg cell population does not comprise effector T cells;
• and
• wherein said thyTreg cell population is obtainable by a method comprising the following steps:
• (a) disaggregating the thymic tissue;
• (b) filtering a product obtained after stage (a), and resuspending a precipitate comprising thymocytes in a culture medium;
• (c) isolating CD25+ cells from the product obtained after stage (b);
• (d) culturing a cell population obtained after stage (c) in a culture medium in the presence of a T cell activator and IL-2, wherein said T cell activator comprises at least CD3 and CD28 agonists;
• and
• (e) removing the T cell activator from the culture medium of stage (d);
• wherein prior to step (d), the cell population has not been depleted of CD8+ cells.