In vitro inducing effect of dendritic cells cotransfected with survivin and granulocyte-macrophage colony-stimulating factor on cytotoxic T cell to kill leukemic cells:

Regulation of arachidonic acid in esophageal adenocarcinoma cells and tumor-infiltrating lymphocytes

The generation and development of esophageal adenocarcinoma (EAC) are correlated with neuroimmunological factors. The aim of this study was to observe the effectiveness of the neurotransmitter arachidonic acid (AA) on two EAC cell lines, OE19 and SK-GT-4, as well as three isolated tumor-infiltrating lymphocytes (TIL1, 2 and 3). C-X-C chemokine receptor type 4 (CXCR-4) and tumor necrosis factor receptor 1 (TNFR1) expression, cell migration, necrosis, cytokine secretion and cytotoxicity of TILs were investigated. AA dose-dependently increased the migration of all cells. However, AA did not increase the percentage of cell death of the three TILs in the presence of a necrosis-inducing agent. AA dose-dependently increased the cytotoxicity of the three γδT cell-enriched TILs compared with the OE19 and SK-GT-4 cell lines. AA also dose-dependently increased the secretion of interferon-γ (IFN-γ) and TNF-β in TIL1 and 2. However, the cytokine secretion and cytotoxicity activity of TIL3 and γδT cell-enriched TIL3 were the lowest. Furthermore, the percentage of CD4⁺forkhead box p3 (Foxp3)⁺ regulatory T cells in TIL3 was the highest. The effect of AA on tumor cells and TILs is different. The degree of malignancy of the tumor and the ratio of regulatory T cells may be the main factors determining the function of AA.

Critical role of γ4 chain in the expression of functional Vγ4Vδ1 T cell receptor of gastric tumour-infiltrating γδT lymphocytes

Vγ4Vδ1 T cell receptor (TCRγ4δ1)-expressing γδT cells were the most dominant subset in gastric tumour-infiltrating γδT cells (γδTIL) we recently analyzed. To study the essential roles of γ and δ chains in assembly and function of TCRγ4δ1, we sequenced and constructed them into lentiviral vectors for the reconstitution of TCRγ4δ1 using different modalities of transduction. We were able to efficiently reconstitute TCRγ4δ1 with functional activities when both γ4 and δ1 chains are coexpressed in TCR-negative J.RT3-T3.5 cells. However, the expression of δ1 chain is greatly diminished when γ4 expression is absent, suggesting that the coexpressing γ4 is critical in maintaining the folding and stability of δ1 product. To functionally study the reconstituted TCRγ4δ1, we examined the cytolytic activity of TCRγ4δ1-reconstituted J.RT3-T3.5 cells and cytokine secretion and found the receptors are fully functional, but their functionality also requires the presence of γ4. Our results demonstrated that γ4 is critical for the stability of δ1 and the function of TCRγ4δ1.

Flanking V and J sequences of complementary determining region 3 of T cell receptor (TCR) δ1 (CDR3δ1) determine the structure and function of TCRγ4δ1

The γδ T cell receptor (TCR) differs from immunoglobulin and αβ TCR in its overall binding mode. In human, genes δ1, δ2, and δ3 are used for TCRδ chains. Previously, we have studied antigen binding determinants of TCRδ2 derived from dominant γδ T cells residing in peripheral blood. In this study we have investigated the critical determinants for antigen recognition and TCR function in TCRδ1 originated from gastric tumor-infiltrating γδ T lymphocytes using three independent experimental strategies including complementary determining region 3 (CDR3) of TCRδ1 (CDR3δ1)-peptide mediated binding, CDR3δ1-grafted TCR fusion protein-mediated binding, and TCRγ4δ1- and mutant-expressing cell-mediated binding. All three approaches consistently showed that the conserved flanking V and J sequences but not the diverse D segment in CDR3δ1 determine the antigen binding. Most importantly, we found that mutations in the V and J regions of CDR3δ1 also abolish the assembly of TCR and TCR-CD3 complexes in TCRγ4δ1-transduced J.RT3-T3.5 cells. Together with our previous studies on CDR3δ2 binding, our finding suggests that both human TCRδ1 and TCRδ2 recognize antigen predominately via flanking V and J regions. These results indicate that TCRγδ recognizes antigens using conserved parts in their CDR3, which provides an explanation for a diverse repertoire of γδTCRs only recognizing a limited number of antigens.

Gene carriers and transfection systems used in the recombination of dendritic cells for effective cancer immunotherapy

Dendritic cells (DCs) are the most potent antigen-presenting cells. They play a vital role in the initiation of immune response by presenting antigens to T cells and followed by induction of T-cell response. Reported research in animal studies indicated that vaccine immunity could be a promising alternative therapy for cancer patients. However, broad clinical utility has not been achieved yet, owing to the low transfection efficiency of DCs. Therefore, it is essential to improve the transfection efficiency of DC-based vaccination in immunotherapy. In several studies, DCs were genetically engineered by tumor-associated antigens or by immune molecules such as costimulatory molecules, cytokines, and chemokines. Encouraging results have been achieved in cancer treatment using various animal models. This paper describes the recent progress in gene delivery systems including viral vectors and nonviral carriers for DC-based genetically engineered vaccines. The reverse and three-dimensional transfection systems developed in DCs are also discussed.