To investigate the time of rearrangement of the TCR gene in the process of NKT cell differentiation from CD34+ human cord blood cells in vitro.

We isolated the CD34+ human cord blood cells and induced the differentiation of NKT cells by liquid culture including IL-15, FL and SCF for 30 days. In order to detect the time of TCR gene rearrangement in differentiated NKT cell, we performed PCR for TCR-rearrangement excision circles (TRECs) with isolated DNA.

Signal joint TREC first appeared on day 4 or day 8 and continuously existed until day 30. Between day 9 and day 21, cells showed high output of coding joint TRECs after signal joint rearrangement.

In differentiated NKT cells, TCR gene rearrangement started within a week after culture started and mostly occurred in 2 to 3 weeks after culture started.