T lymphocyte costimulatory molecules in host defense and immunologic diseases

Identification of Costimulatory Molecule–Related lncRNAs Associated With Gastric Carcinoma Progression: Evidence From Bioinformatics Analysis and Cell Experiments

Costimulatory molecules (CMGs) play essential roles in multiple cancers. However, lncRNAs regulating costimulatory molecules have not been fully explored in gastric cancer (GC). Public data of GC patients were obtained from The Cancer Genome Atlas database. R software v4.1.1, SPSS v13.0, and GraphPad Prism 8 were used to perform all the analyses. The Limma package was used for differential expression analysis. The survival package was used for patient prognosis analysis. The gene set enrichment analysis (GSEA), gene ontology (GO), and the Kyoto encyclopedia of genes and genomes (KEGG) analysis were used for pathway enrichment analysis. qRT-PCR was used to detect the RNA level of target lncRNA. CCK-8 and colony formation assay were used to assess the proliferation ability of GC cells. The transwell assay was used to evaluate the invasion and migration ability of GC cells. We first identified CMG-related lncRNAs (CMLs) through co-expression analysis. Then, an eight-CML-based signature was constructed to predict patient overall survival (OS), which showed satisfactory predictive efficiency (the training cohort: 1-year AUC = 0.764, 3-year AUC = 0.810, 5-year AUC = 0.840; the validation cohort: 1-year AUC = 0.661, 3-year AUC = 0.718, 5-year AUC = 0.822). The patients in the high-risk group tend to have a worse prognosis. GSEA showed that epithelial–mesenchymal transition, KRAS signaling, and angiogenesis were aberrantly activated in high-risk patients. GO and KEGG analyses indicated that the biological difference between high- and low-risk patients was mainly enriched in the extracellular matrix. Immune infiltration analysis showed that macrophages (M1 and M2), dendritic cells, monocytes, Tregs, and T regulatory cells were positively correlated with the risk scores, partly responsible for the worsening OS of high-risk patients. Finally, lncRNA AP000695.2 was selected for further experiments. The result showed that AP000695.2 was upregulated in GC cell lines and could facilitate the proliferation, invasion, and migration of GC cells. In summary, this study established an effective prognosis model based on eight CMLs, which would be helpful for further therapy options for cancer. Also, we found that AP000695.2 could promote GC cell malignant phenotype, making it an underlying therapy target in GC.

Restoring Herpesvirus Entry Mediator (HVEM) Immune Function in HVEM-/- Mice Rescues Herpes Simplex Virus 1 Latency and Reactivation Independently of Binding to Glycoprotein D

The immune modulatory protein herpes virus entry mediator (HVEM) is one of several cellular receptors used by herpes simplex virus 1 (HSV-1) for cell entry. HVEM binds to HSV-1 glycoprotein D (gD) but is not necessary for HSV-1 replication in vitro or in vivo Previously, we showed that although HSV-1 replication was similar in wild-type (WT) control and HVEM-/- mice, HSV-1 does not establish latency or reactivate effectively in mice lacking HVEM, suggesting that HVEM is important for these functions. It is not known whether HVEM immunomodulatory functions contribute to latency and reactivation or whether its binding to gD is necessary. We used HVEM-/- mice to establish three transgenic mouse lines that express either human WT HVEM or human or mouse HVEM with a point mutation that ablates its ability to bind to gD. Here, we show that HVEM immune function, not its ability to bind gD, is required for WT levels of latency and reactivation. We further show that HVEM binding to gD does not affect expression of the HVEM ligands BTLA, CD160, or LIGHT. Interestingly, our results suggest that binding of HVEM to gD may contribute to efficient upregulation of CD8α but not PD1, TIM-3, CTLA4, or interleukin 2 (IL-2). Together, our results establish that HVEM immune function, not binding to gD, mediates establishment of latency and reactivation.IMPORTANCE HSV-1 is a common cause of ocular infections worldwide and a significant cause of preventable blindness. Corneal scarring and blindness are consequences of the immune response induced by repeated reactivation events. Therefore, HSV-1 therapeutic approaches should focus on preventing latency and reactivation. Our data suggest that the immune function of HVEM plays an important role in the HSV-1 latency and reactivation cycle that is independent of HVEM binding to gD.

Defining dose-response relationships in the therapeutic blockade of B7RP-1-dependent immune responses

The ICOS (Inducible T cell Co-Stimulator)/B7RP-1 (B7-related protein 1) interaction is critical for the proper activation of a T lymphocyte. In this manuscript we describe a systematic in vivo approach to determine the level of blockade required to impair the generation of a T cell-dependent antibody response. We have developed an overall strategy for correlating drug exposure, target saturation, and efficacy in a biological response that can be generalized for most protein therapeutics. Using this strategy, we determined that low levels of B7RP-1 blockade are still sufficient to inhibit the immune response. These data suggest that contact between the T cell and the antigen-presenting cell during antigen presentation is much more sensitive to inhibition than previously believed and that ICOS/B7RP-1 blockade may be efficacious in the treatment of autoimmune diseases.

Skin immunity

As the major barrier of the body to the outside, the skin is constantly confronted with microbial, chemical and physical insults. However, the skin does not only function as a mechanical barrier but also uses the immune system for protection. Therefore, the skin is endowed with the capacity to generate immune responses of the innate as well as of the adaptive type.

Cutting edge: membrane lymphotoxin regulates CD8(+) T cell-mediated intestinal allograft rejection

Blocking the CD28/B7 and/or CD154/CD40 costimulatory pathways promotes long-term allograft survival in many transplant models where CD4(+) T cells are necessary for rejection. When CD8(+) T cells are sufficient to mediate rejection, these approaches fail, resulting in costimulation blockade-resistant rejection. To address this problem we examined the role of lymphotoxin-related molecules in CD8(+) T cell-mediated rejection of murine intestinal allografts. Targeting membrane lymphotoxin by means of a fusion protein, mAb, or genetic mutation inhibited rejection of intestinal allografts by CD8(+) T cells. This effect was associated with decreased monokine induced by IFN-gamma (Mig) and secondary lymphoid chemokine (SLC) gene expression within allografts and spleens respectively. Blocking membrane lymphotoxin did not inhibit rejection mediated by CD4(+) T cells. Combining disruption of membrane lymphotoxin and treatment with CTLA4-Ig inhibited rejection in wild-type mice. These data demonstrate that membrane lymphotoxin is an important regulatory molecule for CD8(+) T cells mediating rejection and suggest a strategy to avoid costimulation blockade-resistant rejection.