Background and Purpose— Intracerebral hemorrhage (ICH) is a neurologically destructive stroke, for which no valid treatment is available. This preclinical study examined the therapeutic effect of PD-L1 (programmed death ligand 1), a B7 family member and a ligand for both PD-1 (programmed death 1) and B7-1 (CD80), in a murine ICH model. Methods— ICH was induced by injecting autologous blood into 252 male C57BL/6 and Rag1 −/− mice. One hour later, ICH mice were randomly assigned to receive an intraperitoneal injection of vehicle, PD-L1, or anti–PD-L1 antibody. Neurological function was assessed along with brain edema, brain infiltration of immune cells, blood–brain barrier integrity, neuron death, and mTOR (mammalian target of rapamycin) pathway products. Results— PD-L1 significantly attenuated neurological deficits, reduced brain edema, and decreased hemorrhage volume in ICH mice. PD-L1 specifically downsized the number of brain-infiltrating CD4 + T cells and the percentages of Th1 and Th17 cells but increased the percentages of Th2 and regulatory T cells. In the PD-L1–treated group, we observed an amelioration of the inflammatory milieu, decreased cell death, and enhanced blood–brain barrier integrity. PD-L1 also inhibited the mTOR pathway. The administration of anti–PD-L1 antibody produced the opposite effects to those of PD-L1 in ICH mice. Conclusions— PD-L1 provided protection from the damaging consequences of ICH.

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Cell-based assays (CBAs) and radioimmunoprecipitation assay (RIPA) are the most sensitive methods for identifying anti-acetylcholine receptor (AChR) antibody in myasthenia gravis (MG). But CBAs are limited in clinical practice by transient transfection. We established a stable cell line (KL525) expressing clustered AChR by infecting HEK 293T cells with dual lentiviral vectors expressing the genes encoding the human AChR α1, β1, δ, ϵ and the clustering protein rapsyn. We verified the stable expression of human clustered AChR by immunofluorescence, immunoblotting, and real-time PCR. Fluorescence-activated cell sorting (FACS) was used to detect anti-AChR antibodies in 103 MG patients and 58 healthy individuals. The positive results of MG patients reported by the KL525 was 80.6% (83/103), 29.1% higher than the 51.4% (53/103) of RIPA. 58 healthy individuals tested by both the KL525 CBA and RIPA were all negative. In summary, the stable expression of clustered AChR in our cell line makes it highly sensitive and advantageous for broad clinical application in CBAs.