Potent immunostimulatory dendritic cells can be cultured in bulk from progenitors in normal infant and adult myasthenic human thymus

Low density cells can readily be enriched from thymus tissue both of childr en undergoing cardiac surgery and of older patients with myasthenia gravis, and can be cryostored in bulk. When fresh or thawed cells are cultured wit h granulocyte-macrophage colony-stimulating factor and stem cell factor wit h or without tumour necrosis factor-alpha (TNF-alpha), they generate numero us cells with the characteristic ultrastructural, phenotypic and functional properties of dendritic cells. These proved to be very potent, both as sti mulators of primary mixed leucocyte responses and as costimulators in oxida tive mitogenesis. Especially after exposure to TNF-alpha, these dendritic c ells also processed a natural epitope from a 437-residue polypeptide and pr esented it efficiently to an autoimmune T-cell clone (of T helper type 0 ph enotype). Thus, immunostimulatory dendritic cells can be cultured in relati ve abundance from progenitors in infant and adult human thymus. Both are co nvenient sources of potent antigen-presenting cells of identifiable origins , e.g. for use in selecting human T-cell lines.