Cytolytic Activity of Decidual CD8+

Cytolytic Activity of Decidual CD8+ LymphocytesCD8+ decidual lymphocytes from normal early pregnancy samples exhibited cytolytic activity against P815 target cells. The results for all samples are summarized in Figure 2. The mean %SCR32 for normal pregnancy samples (n = 11) was 32.7 ± 5.8. With the exception of one sample at 12 wks GA, which had a mean %SCR32 of 80.1, the cytolytic activity of decidual CD8+ lymphocytes did not appear to significantly vary between the 7- to 14-wk GA range (data not shown); but due to the small subject numbers for each GA week, statistical analysis was not performed. Decidual CD8+ lymphocytes also exhibited cytolytic activity against K562 cells in a standard chromium release assay (n = 3). The mean %SCR32 was 20.3 ± 0.5 (Fig. 2). There was no difference in cytolytic ability between the redirected chromium release assay and the standard chromium release assay.Cytokine Production by Decidual CD8+ T LymphocytesDetectable levels of CSF2, IFNG, IL1B, IL2, IL6, IL8, IL10, IL12, and TNF were found in decidual CD8+ T lymphocyte culture supernatants after incubation of 24 (n = 21) and 48 (n = 21) h. Levels of IL4 fell below the range of the Luminex assay. As cytokine levels in supernatants did not differ between 24- and 48-h incubation samples (data not shown) for any of the cytokines examined, the cytokine levels from 48-h supernatants were used for analysis of GA-associated changes in cytokine production.Levels of CSF2, IL1B, IL2, IL10, IL12, and TNF did not vary among the GA groups examined (Fig. 3). Levels of IL6 from the 11-wk group were higher than in the other GA supernatants, but this did not reach significance. Both IL8 and IFNG were detected at high levels in all decidual CD8+ T lymphocyte supernatants with no GA changes (Fig. 3).Effect of Decidual CD8+ T Lymphocyte Culture Supernatants on Trophoblast InvasionDecidual CD8+ T lymphocyte supernatants increased the capacity of extravillous trophoblast cells to invade through Matrigel when compared with the PHA-P control (n = 16, mean number of invaded cells normalized to PHA-P ± SEM: 280 ± 61.3 vs. 100 ± 0, P = 0.006; Fig. 4). When the PHA-P control was compared with medium-alone controls, there was no difference in the number of invaded extravillous trophoblast cells (data not shown). When analyzed by GA, supernatants from 8-wk samples increased invasion (n = 6, 263 ± 54.5) compared with the PHA-P control (100 ± 0, P = 0.001; Fig. 4). Decidual CD8+ T lymphocyte supernatants from 10- (n = 4) and 12-wk (n = 6) GA samples also showed a trend to increase extravillous cytotrophoblast cell invasion compared with the PHA-P control (data not shown), but this did not reach statistical significance.