Different responses of lymphocyte to human placenta conditioned medium in vitro.

Several cytokines appear to be implicated in peri-implantation events and in maternal-fetal interaction. The majority of these molecules appear in supernatants or in extracts of placental origin. The purpose of this study was to investigate the action of human placenta conditioned medium (HPCM) on peripheral lymphocytes in vitro. Peripheral lymphocytes of women with different numbers of deliveries, of nulliparous and pregnant women, as well as of men, were cultivated in their own plasma with and without HPCM at 5%, 10% and 20%. The index of lymphocyte blast transformation (ILBT) was determined (values of > or = 0.5 indicated stimulation). In women who had had children, the highest lymphocyte blastogenesis was observed with HPCM at 10%, this finding being correlated to the numbers of deliveries (r = 0.828). In pregnant women, even though the highest answer was also obtained with HPCM at 10%, the addition of suboptimal concentration of HPCM (5%) produced blastic transformation (IBLT: x = 0.54 +/- 0.05), which was not observed in women who had had children. Lymphocytes of men and nulliparous women did not respond to any of the HPCM concentrations tested. In conclusion, HPCM at 10% was still the best concentration to produce lymphocyte blastogenesis. In addition, in the plasma of pregnant women, there may be some substance that enhanced the action in vitro of the extract, thus permitting threshold reduction necessary for lymphocyte stimulation.

Human placenta conditioned medium as a source of lymphocyte blastogenesis in vitro.

The purpose of this work was to obtain placental extracts with the capacity of producing lymphocyte blastogenesis. Placental homogenates were incubated at 37 degrees C in McCoy's 5A supplemented with 5% fetal bovine serum and 25 mM Hepes. After a 6-day incubation period, the cultures were harvested and the sterility and cellular viability were controlled. The supernatant was centrifuged at 22,000g at 4 degrees C for 30 minutes. Sterilization was achieved by filtration (0.22 microns). This medium was denominated human placenta conditioned medium (HPCM-1). The other half of the original placenta was processed by the Burgess method and the extracts thus obtained were denominated HPCM-2. The activity of the extracts thus obtained was tested in peripheral lymphocyte cultures from women after the third pregnancy; 5, 10 and 20% HPCM-1 or HPCM-2 was added to these cultures and the index of lymphocyte blast transformation (ILBT) was determined. The highest stimulation occurred at 10% HPCM. The ILBT obtained with HPCM-1 at 10% was more constant than that obtained with HPCM-2 at the same concentration. In conclusion, it can be assumed that this methodology is appropriate to obtain conditioned media from human placenta with good blastogenic activity on peripheral lymphocytes in vitro.