CONTINUOUS HUMAN EMBRYONIC STEM CELL LINES
T. A. Krylova, V. V. Zenin, N. A. Mikhailova, G. P. Pinaev, N. N. Nikolsky,
G. G. Poljanskaya 1
Institute of Cytology RAS, St. Petersburg, Russia;
1 e-mail: poljansk@mail.cytspb.rssi.ru
A new continuous human embryonic stem cell line (HESC-5) derived from a blastocyst is described. The cultured cell
passed over 200 population doublings, which exceeds the Hayflick's limit sufficiently. The cells maintained a stable proliferative
activity, high activity of alkaline phosphatase, and expression of transcription factor Oct-4 and of surface antigens SSEA-3, SSEA-4 and
TRA-1-60 known to be characteristic of embryonic stem cells of the human origin. Immunofluorescent detection of antigens, characteristic
of ectoderm, endoderm and mesoderm in the new cell line HESC-5, and in the previously described other four stem cell lines confirms the
ability of these cells to retain their pluripotency under in vitro condition. In addition, in all the cell lines, a high telomerase
activity was revealed, which controls a stable telomere length and, hence, an unlimited ESC proliferation. Unlike other cell lines,
HESC-5 was found, under specific conditions, to spontaneously differentiate into hematopoietic cells. A morphological similarity was
shown between ESC colonies cultivated both on a feeder layer and in the non-feeder system.
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