Equivalent functional nuclear factor of activated T cell 1 mRNA and protein expression in cord blood and adult T cells.

Cord blood (CB) cells are now an important source of stem cells for bone marrow reconstitution as a result of the decreased risk of graft-versus-host disease that was attributed to previously reported absent or diminished nuclear factor of activated T (NFAT) cell 1 expression by CB T cells. This study reexamines NFAT1 expression in CB T cells. CB T cells were examined for NFAT1 mRNA and protein expression. These cells were then stimulated, and NFAT1 translocation and interleukin-2 production were assessed. Our results show that resting CB CD4+ T cells express NFAT1 mRNA and protein at levels similar to their adult counterparts. On stimulation, NFAT1 is translocated into the nucleus where DNA binding can occur, whereas calcineurin inhibition prevents interleukin-2 production. We conclude that differential responsiveness of CB T cells cannot be attributed to differences at the level of NFAT1 expression or its ability to function in these cells but may represent an altered sensitivity to stimulation.