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. Author manuscript; available in PMC: 2021 Jun 10.
Published in final edited form as: J Leukoc Biol. 2020 May 9;108(3):983–998. doi: 10.1002/JLB.1A0420-012RR

Figure 11. Trophoblast constitutively secrete soluble PD-L1, and it is regulated by IFN-β.

Figure 11.

A. Expression levels of secreted PD-L1 detected in trophoblast supernatants by ELLA assay. Supernatants were collected from 100% confluent Swan 71 trophoblast cells at different times and PD-L1 expression was quantified by ELLA assay. Note the increase of sPD-L1 in the supernatant in a time dependent manner.

B. Trophoblast Swan 71 cells were treated with or without IFN-β (12.5 IU/ml) for 8, 16, 24 and 48h, after which PD-L1 mRNA expression was determined by qPCR. IFN-β induced a 6-fold increase in mRNA expression within 8h of treatment and remained higher than the control for an additional 48h. Data is presented as fold changes between the IFN-β treated group compared to the non-treated control group.

C. Trophoblast Swan 71 cells were treated with or without IFN-β (12.5 IU/ml) for 24 and 48h, after which PD-L1 protein expression was determined in total cell lysate by western blot analysis. Trophoblast cells constitutively express intracellular PDL-1 protein, but it is not affected by IFN-β treatment.

D. Trophoblast Swan 71 cells were treated with or without IFN-β (12. 5 IU/ml) for 24 and 48 hr, after which supernatants were collected and sPD-L1 protein expression was determined by ELLA assay. IFN-β treatment of trophoblast cells enhances the concentration of soluble PD-L1 detected in the supernatants in a time dependent manner. n=6 individual experiments.