Characterization of Publicly Available Lymphoblastoid Cell Lines for Disease-Associated Mutations in 11 Genes

B Cells Control Mucosal-Associated Invariant T Cell Responses to Salmonella enterica Serovar Typhi Infection Through the CD85j HLA-G Receptor

Mucosal-associated invariant T (MAIT) cells are an innate-like population of T cells that display a TCR Vα7.2+ CD161+ phenotype and are restricted by the nonclassical MHC-related molecule 1 (MR1). Although B cells control MAIT cell development and function, little is known about the mechanisms underlying their interaction(s). Here, we report, for the first time, that during Salmonella enterica serovar Typhi (S. Typhi) infection, HLA-G expression on B cells downregulates IFN-γ production by MAIT cells. In contrast, blocking HLA-G expression on S. Typhi-infected B cells increases IFN-γ production by MAIT cells. After interacting with MAIT cells, kinetic studies show that B cells upregulate HLA-G expression and downregulate the inhibitory HLA-G receptor CD85j on MAIT cells resulting in their loss. These results provide a new role for HLA-G as a negative feedback loop by which B cells control MAIT cell responses to antigens.

Global profiling of viral and cellular non-coding RNAs in Epstein-Barr virus-induced lymphoblastoid cell lines and released exosome cargos

The human EBV-transformed lymphoblastoid cell line (LCL), obtained by infecting peripheral blood monocular cells with Epstein-Barr Virus, has been extensively used for human genetic, pharmacogenomic, and immunologic studies. Recently, the role of exosomes has also been indicated as crucial in the crosstalk between EBV and the host microenvironment. Because the role that the LCL and LCL exosomal cargo might play in maintaining persistent infection, and since little is known regarding the non-coding RNAs of LCL, the aim of our work was the comprehensive characterization of this class of RNA, cellular and viral miRNAs, and cellular lncRNAs, in LCL compared with PBMC derived from the same donors. In this study, we have demonstrated, for the first time, that all the viral miRNAs expressed by LCL are also packaged in the exosomes, and we found that two miRNAs, ebv-miR-BART3 and ebv-miR-BHRF1-1, are more abundant in the exosomes, suggesting a microvescicular viral microRNA transfer. In addition, lncRNA profiling revealed that LCLs were enriched in lncRNA H19 and H19 antisense, and released these through exosomes, suggesting a leading role in the regulation of the tumor microenvironment.

Genetically Characterized Positive Control Cell Lines Derived from Residual Clinical Blood Samples

Background: Positive control materials for clinical diagnostic molecular genetic testing are in critically short supply. High-quality DNA that closely resembles DNA isolated from patient specimens can be obtained from Epstein–Barr virus (EBV)–transformed peripheral blood lymphocyte cell lines. Here we report the development of a process to (a) recover residual blood samples with clinically important mutations detected during routine medical care, (b) select samples likely to provide viable lymphocytes for EBV transformation, (c) establish stable cell lines and confirm the reported mutation(s), and (d) validate the cell lines for use as positive controls in clinical molecular genetic testing applications.

Methods: A network of 32 genetic testing laboratories was established to obtain anonymous, residual clinical samples for transformation and to validate resulting cell lines for use as positive controls. Three panel meetings with experts in molecular genetic testing were held to evaluate results and formulate a process that could function in the context of current common practices in molecular diagnostic testing.

Results: Thirteen laboratories submitted a total of 113 residual clinical blood samples with mutations for 14 genetic disorders. Forty-one EBV-transformed cell lines were established. Thirty-five individual point and deletion mutations were shown to be stable after 20 population doublings in culture. Thirty-three cell lines were characterized for specific mutations and validated for use as positive controls in clinical diagnostic applications.

Conclusions: A process for producing and validating positive control cell lines from residual clinical blood samples has been developed. Sustainable implementation of the process could help alleviate the current shortage of positive control materials.