At approximately day 1

Single positive T cells detectable in the spleen.

Reference [PubMed Link]

West LJ. 2002 Sep-Oct. Defining critical windows in the development of the human immune system. Hum Exp Toxicol 21(9-10):499-505.

At approximately day 1

Functional capability of fetal T lymphocytes begins to develop through week 26.

Duration: 12 weeks

Reference [PubMed Link]

West LJ. 2002 Sep-Oct. Defining critical windows in the development of the human immune system. Hum Exp Toxicol 21(9-10):499-505.