EXPANSION OF CD3+CD8+ T LYMPHOCYTES FROM HUMAN CORD BLOOD

Abstract

Human cord blood (CB) has been used as a source of allogeneic hematopoietic stem cells for
patients of hematologic malignancies as it lowers the risk of graft versus host effect while
delivering more graft versus tumor effect. T cell immunotherapy can be developed from CB,
however, with the limited volume of cord blood collected and stored in CB banks, procedures to
expand T lymphocytes to a sufficient number are urgently required. Hence, we conduct the study
with an aim of establishing an optimal procedure for isolation and expansion of T lymphocytes
from human cord blood that meets the requirement for cell therapy in cancer treatment. Three CB
mononuclear cell (MNC) samples were collected by Ficoll and then the T cells were expanded by
using BINKIT kit from Biotherapy Institute of Japan. After 20 days of culture, the average number
of CD3+CD8+ T cells reached 890.3±150.3×106 cells, increased 403.8±240 times compared to
the number of these cells at seeding. The purity of cell population was not high, with the average
percentage of CD3+CD8+ T cells (%) in the total cell was 49.4±10%, meanwhile this value of CD3+
T cells was 74.5±14.4%. Of note, 2/3 samples had the decrease in the number of CD3+CD8+ T
cells at day 20 compared to day 13 of culture. In conclusion, we were successful in expansion of
CD3+CD8+ T cells from human cord bloods, with the adequate number for the cell therapy.
However, the length of cell culture should be considered for each individual sample and the
selection of CD3+CD8+ T cells at seeding should be carried out in order to increase the purity of
cell population after expansion.