PROGESTERONE INDUCED A SELECTIVE APOPTOSIS OF PERIPHERAL BLOOD CD56 dim

L.ARRUVITO; M.BARBOZA; A.C.FLORES; L.FAINBOIM

Córdoba, Argentina

Congreso; VII Congreso Latinoamericano de Inmunología. ALAI. Argentina, Córdoba, Octubre 2005; 2005

Around 90% of peripheral blood Natural Killer (PBNK) cells are CD56 dim CD16+ and the other 10% are CD56 bright and CD16 – . In normal endometrium most natural killer (uNK) are CD56 brightCD16(). The uNK and T regulatory cells (Treg), are upregulated along normal pregnancy. We investigated the putative role of 17ßestradiol or progesterone on the differential induction of apoptosis upon different lymphocytes subsets. Flow cytometry analysis revealed that neither 17ßestradiol nor progesterone had significant effects on the frequency of Treg cells or on CD56 bright CD16(-). In contrast, after 72 hs of cell culture, only progesterone induced the dead of CD56+ cells (35 to 50%). We next enriched the PBNK cells either by a 10 days activation of PBMCs with the RPMI 8866 cell line or by immunomagnetic negative selection from PBMCs. Purified PBNK cells (>90%) cultured for 48hs in the presence or absence of different concentrations of progesterone (10 –6M , 10 –7M and 10 8M) showed a dose dependent early plus late apoptosis of the purified CD56 dim CD16cells (70%, 60 and 55% respectively). Thus, progesterone induced a selective apoptosis of the cytotoxic CD56 dim CD16+ without affecting CD56 bright cells allowing the selective expression of the noncytotoxic CD56 bright uNK in the uterus, and seems to preserve the presence of the Treg cells that show a dramatic increase during pregnancy.