TaqMan Real-time RT-PCR Assay for Detecting and Differentiating Japanese Encephalitis Virus

Objective To detect Japanese encephalitis virus（JEV） rapidly and distinguish its genotypes, a TaqMan-based reverse transcriptase quantitative polymerase chain reaction（RT-PCR） detection system was developed.Methods By aligning the full-length sequences of JEV（G1-G5）, six sets of highly specific TaqMan real-time RT-PCR primers and probes were designed based on the highly conserved NS1, NS2, and M genes of JEV, which included one set for non-specific JEV detection and five sets for the detection of specific JEV genotypes. Twenty batches of mosquito samples were used to evaluate our quantitative PCR assay.Results With the specific assay, no other flavivirus were detected. The lower limits of detection of the system were 1 pfu/mL for JEV titers and 100 RNA copies/μL. The coefficients of variation of this real-time RT-PCR were all 〈 2.8%. The amplification efficiency of this method was between 90% and 103%.Conclusion A TaqMan real-time RT-PCR detection system was successfully established to detect and differentiate all five JEV genotypes.

Immunophenotypic characteristics of multipotent mesenchymal stromal cells that affect the efficacy of their use in the prevention of acute graft vs host disease

BACKGROUND Multipotent mesenchymal stromal cells(MSCs)are widely used in the clinic due to their unique properties,namely,their ability to differentiate in all mesenchymal directions and their immunomodulatory activity.Healthy donor MSCs were used to prevent the development of acute graft vs host disease(GVHD)after allogeneic bone marrow transplantation(allo-BMT).The administration of MSCs to patients was not always effective.The MSCs obtained from different donors have individual characteristics.The differences between MSC samples may affect their clinical efficacy.AIM To study the differences between effective and ineffective MSCs.METHODS MSCs derived from the bone marrow of a hematopoietic stem cells donor were injected intravenously into allo-BMT recipients for GVHD prophylaxis at the moment of blood cell reconstitution.Aliquots of 52 MSC samples that were administered to patients were examined,and the same cells were cultured in the presence of peripheral blood mononuclear cells(PBMCs)from a third-party donor or treated with the pro-inflammatory cytokines IL-1β,IFN and TNF.Flow cytometry revealed the immunophenotype of the nontreated MSCs,the MSCs cocultured with PBMCs for 4 d and the MSCs exposed to cytokines.The proportions of CD25-,CD146-,CD69-,HLA-DR-and PD-1-positive CD4+and CD8+cells and the distribution of various effector and memory cell subpopulations in the PBMCs cocultured with the MSCs were also determined.RESULTS Differences in the immunophenotypes of effective and ineffective MSCs were observed.In the effective samples,the mean fluorescence intensity(MFI)of HLAABC,HLA-DR,CD105,and CD146 was significantly higher.After MSCs were treated with IFN or cocultured with PBMCs,the HLA-ABC,HLA-DR,CD90 and CD54 MFI showed a stronger increase in the effective MSCs,which indicated an increase in the immunomodulatory activity of these cells.When PBMCs were cocultured with effective MSCs,the proportions of CD4+and CD8+central memory cells significantly decreased,and the proportion of CD8+CD146+lymphocytes increased more than in the subpopulations of lymphocytes cocultured with MSC samples that were ineffective in the prevention of GVHD;in addition,the proportion of CD8+effector memory lymphocytes decreased in the PBMCs cocultured with the effective MSC samples but increased in the PBMCs cocultured with the ineffective MSC samples.The proportion of CD4+CD146+lymphocytes increased only when cocultured with the inefficient samples.CONCLUSION For the first time,differences were observed between MSC samples that were effective for GVHD prophylaxis and those that were ineffective.Thus,it was shown that the immunomodulatory activity of MSCs depends on the individual characteristics of the MSC population.