Efficient generation of human T cells from a tissue-engineered thymic organoid

Biocompatible inorganic matrices have been used to enhance bone repair by i ntegrating with endogenous bone architecture. Hypothesizing that a three-di mensional framework might support reconstruction of other tissues as well, we assessed the capacity of a tantalum-coated carbon matrix to support reco nstitution of functioning thymic tissue. We engineered a thymic organoid by seeding matrices with murine thymic stroma. Co-culture of human bone marro w-derived hematopoietic progenitor cells within this xenogeneic environment generated mature functional T cells within 14 days. The proportionate T-ce ll yield from this system was highly reproducible, generating over 70% CD3( +) T cells from either AC133(+) or CD34(+) progenitor cells. Cultured T cel ls expressed a high level of T-cell receptor excision circles (TREC), demon strating de novo T lymphopoiesis, and function of fully mature T cells. Thi s system not only facilitates analysis of the T-lymphopoietic potential of progenitor cell populations; it also permits ex vivo genesis of T cells for possible applications in treatment of immunodeficiency.