CD1 Antigen Presentation and Autoreactivity in the Pregnant Human Uterus.

CD11c(HI) human decidual macrophages express several isoforms of CD1 molecules. Their expression pattern and function required investigation. CD11c(HI) macrophages were isolated from decidua. Expression of CD1 isoforms and their ability to present lipid antigens to T cells was studied. CD1a, CD1c, and CD1d were all expressed on CD11c(HI) dMϕ, a pattern differing from those previously observed. Exposure of peripheral monocytes and dendritic cells to lipid isolates from decidua led to increased surface CD1a levels only. The CD1a and CD1c on dMϕ were able to present the appropriate lipid antigens to lipid antigen-specific T cells. Finally, autoreactivity of decidual T cells to CD1a was observed. The unique pattern of expression of CD1 isoforms on CD11c(HI) dMϕ is consistent with organ-specific roles of CD1 in human T-cell responses. dMϕ are able to present lipid antigens to both peripheral and decidual T cells and are major antigen-presenting cells in human decidua.