PROBLEM: Implantation of human embryo requires expression of inflammatory c
ytokines and local attraction of T cells and natural killer (NK) cells. Che
mokines are chemoattractants for these cells in classical inflammation. We
speculated that they could also be involved in implantation.
METHOD OF STUDY: We assessed by enzyme-linked immunosorbent assay (ELISA),
reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistoche
mistry the presence of three classical beta chemokines Macrophage Inflammat
ory Protein 1 (MIP1)alpha, MIP1 beta and Regulated upon activation, normal
T cells expressed and secreted (RANTES) in cultures of placental villi or i
solated trophoblasts derived from human first trimester and term placenta.
RESULTS: Explant culture assays were positive for these three chemokines, w
ith important quantitative variations between individuals. Half of the high
ly purified trophoblasts cultures were found by ELISA and RT-PCR to secrete
in vitro MIP1 alpha and MIP1 beta. RANTES was never detected by ELISA in t
rophoblasts cultures, albeit we could detect a low amount of messenger RNA.
Immunohistochemistry experiments show that Hofbauer cells and the trophobl
ast layer are a secretion site of MIP1 beta in term placenta, and that cyto
trophoblasts are able to secrete this chemokine in early placenta.
CONCLUSION: Human placenta is a site of secretion of chemokines that could
be involved in establishment of pregnancy.