Identifiation and characterisation of human fetal antigen presenting cells subsets.

The human immune system evolves gradually from the embryo to adult, continuously adapting to the ever-changing environment of the human body. The ability of our immune system to sense external cues and adapt as we develop is as important in the early tolerogenic environment of the fetus, as it is in the constantly pathogen-challenged adult. Dendritic cells (DC), professional antigen sensing and presenting cells, play a crucial role in such processes as sentinels of the immune system, initiating and regulating immune responses. We have previously characterised CD14+ DC, CD1c+DC and CD141+DC subset by flow cytometry and microarray transcriptome analysis in adult mucosal tissues, and have described their superior abilities to either induce IL-17 responses or to cross-present external antigens respectively. However, the role of such DC subsets in the tolerogenic environment of the fetus remains undefined, prompting us to investigate the ontogeny and functional significance of human fetal DCs. APC were isolated from fetal (17-22 wk EGA) skin and spleen that was collagenase digeseted for 1hr by FACS. Gene expression analysis using total RNA from specific human APC subsets purified by FACS was performed.