Table 3.

Expression of trophoblast markers and markers for trophoblast subpopulations in primary first trimester trophoblasts, ACH-3P and AC1-1. The expression of the trophoblast marker cytokeratin-7 (CK7) was determined by immunocytochemistry and of markers for trophoblast subtypes (HLA-G, integrins) were detected by FACS analysis. Secretion of hCG was measured after 24 hours in the culture supernatant and normalized to the cell number. The activity of MMP2 and MMP9 was measured by gelatin gel zymography. + indicates ~20–40% of cells. ++ indicates ~40–90%; +++ indicates 100% of cells; – indicates no expression.

	FT	ACH-3P	AC1-1
CK7	+++	+++	+++
Vimentin	-	-	-
HLA-G	++/-	++/-	++
integrin α6	+	++	+
integrin β4	+	++	++
integrin α5β1	+/-	++	++
integrin α1	+/-	-	-
hCG	+++	+	+
MMP2	++	+	+
MMP9	+	+	+++