Development of genetically engineered iNKT cells expressing TCRs specific for the M. tuberculosis 38-kDa antigen

Abstract

IntroductionThe invariant natural killer T (iNKT) cell has been shown to play a central role in early stages immune responses against Mycobacterium tuberculosis (Mtb) infection, which become nonresponsive (anergic) and fails to control the growth of Mtb in patients with active tuberculosis. Enhancement of iNKT cell responses to Mtb antigens can help to resist infection.Study design and methodsIn the present study, an Mtb 38-kDa antigen-specific T cell receptor (TCR) was isolated from human CD8+ T cells stimulated by 38-kDa antigen in vitro, and then transduced into primary iNKT cells by retrovirus vector.ResultsThe TCR gene-modified iNKT cells are endowed with new features to behave as a conventional MHC class I restricted CD8+ T lymphocyte by displaying specific antigen recognition and anti-Mtb antigen activity in vitro. At the same time, the engineered iNKT cells retaining its original capacity to be stimulated proliferation by non-protein antigens α-Gal-Cer.ConclusionsThis work is the first attempt to engineer iNKT cells by exogenous TCR genes and demonstrated that iNKT cell, as well as CD4+ and CD8+ T cells, can be genetically engineered to confer them a defined and alternative specificity, which provides new insights into TCR gene therapy for tuberculosis patients, especially those infected with drug-resistant Mtb.

Microarray analysis of long noncoding RNA and mRNA expression profiles in human macrophages infected with Mycobacterium tuberculosis

“…Then, PBMCs were isolated by the above methods. Monocytes were purified from PBMC by positive selection with CD14 + magnetic bead (miniMACS, Miltenyi Biotec, Gladbach, Germany) and were differentiated into monocyte derived macrophages (MDMs) by treating with macrophage colony-stimulating factor (GM-CSF) as previously described39. Briefly, CD14 + monocytes were culture in RPMI-1640 (Corning, NY, USA) containing 10% fetal bovine serum (FBS) and 1000 U/mL of GM-CSF for 7 days, and the medium was half-changed every 48 hours.…”

Novel Approaches to Exploiting Invariant NKT Cells in Cancer Immunotherapy

“…Using autologous 38-kDa protein pulsed Mo-DCs as APC, they confirmed that only rTCR-expressing iNKT cells recognized and killed these cells. The relative killing efficiency of α-GalCer-pulsed Mo-DCs was similar to the killing of 38-kDa pulsed Mo-DCs, suggesting that the endogenous iNKT TCR was still fully functional ( 77 ). However, it was not determined if the recombinant TCR and the endogenous TCR could both signal at the same time to cause additive or synergistic effects.…”

“…Jiang et al have provided the first evidence of iNKT cells being able to express a second recombinant TCR ( 77 ). In this study, a HLA class I-restricted TCR (TCR-Vα9 TCR-Vβ5) against the Mycobacterium tuberculosis (Mtb) 38-kDa protein was cloned and expressed in iNKT cells.…”

Residual inflammation and viral reservoirs

“…Additionally, effector memory CD4 + T cells more frequently harbor proviruses with identical sequences than less differentiated CD4 + T-cell subsets, indicating that clonal expansion of HIV-infected cells is a characteristic of differentiated cells. Higher frequencies of these differentiated cells were observed in virally suppressed individuals with persistent lymphopenia [77] suggesting that homeostatic proliferation may drive HIV persistence in this group of subjects. IL-7 is a major contributor to CD4 + T cell proliferation in vivo [78].…”