Formation of spheriods by cultured human diploid cells

: When human lung diploid fibroblasts are grown in micro-wells in presence of the organic buffer HEPES in an atmosphere of 5% of CO2, the cells migrate and form spheroids. Histologic examination reveals the presence of fibroblastic and epithelioid cells in these spheroids. Signs of degeneration are seen in both cell types under the electron microscope. Following dissociation of the spheroids and their subculture in absence of HEPES, the cells reverse to their original fibroblast-like morphology and grow in monolayer.