1. Spencer, J., Dillon, S. B., Isaacson, P. G. & Macdonald, T. T. T cell subclasses in fetal ileum. Clin. Exp. Immunol. 65, 553–558 (1986).
2. Howie, D. et al. Extrathymic T cell differentiation in the human intestine early in life. J. Immunol. 161, 5862–5872 (1998).
3. McGovern, N. et al. Human fetal dendritic cells promote prenatal T cell immune suppression through arginase-2. Nature 546, 662–666 (2017).
4. Spencer, J., MacDonald, T. T., Finn, T. & Isaacson, P. G. The development of gut associated lymphoid tissue in the terminal ileum of fetal human intestine. Clin. Exp. Immunol. 64, 536–543 (1986).
5. Halkias, J. et al. CD161 contributes to prenatal immune suppression of IFN-γ-producing PLZF+ T cells. J. Clin. Invest. 130, 3562–3577 (2019).