Development of genetically engineered CD4+ and CD8+ T cells expressing TCRs specific for a M. tuberculosis 38-kDa antigen

Beyond CAR T cells: exploring alternative cell sources for CAR-like cellular therapies

Chimeric antigen receptor (CAR)-T cell therapy has led to remarkable clinical outcomes in the treatment of hematological malignancies. However, challenges remain, such as limited infiltration into solid tumors, inadequate persistence, systemic toxicities, and manufacturing insufficiencies. The use of alternative cell sources for CAR-based therapies, such as natural killer cells (NK), macrophages (MΦ), invariant Natural Killer T (iNKT) cells, γδT cells, neutrophils, and induced pluripotent stem cells (iPSC), has emerged as a promising avenue. By harnessing these cells' inherent cytotoxic mechanisms and incorporating CAR technology, common CAR-T cell-related limitations can be effectively mitigated. We herein present an overview of the tumoricidal mechanisms, CAR designs, and manufacturing processes of CAR-NK cells, CAR-MΦ, CAR-iNKT cells, CAR-γδT cells, CAR-neutrophils, and iPSC-derived CAR-cells, outlining the advantages, limitations, and potential solutions of these therapeutic strategies.

IP10-CDR3 Reduces The Viability And Induces The Apoptosis Of Ovarian Cancer Cells By Down-Regulating The Expression Of Bcl-2 And Caspase 3

PURPOSE

This study aimed to explore the effects of interferon-γ inducible protein 10 (IP10) and complementarity-determining region 3 (CDR3) of T cells receptor on ovarian cancer cells and the involved mechanisms.

METHODS

IP10 and CDR3 were linked with single-chain antibody (scfv) and exotoxin gene muton of Pseudomonas aeruginosa (PE40) to construct IP10-CDR3scfv and IP10-CDR3-PE40scfv. Then, we constructed pcDNA3.1-IP10-CDR3scfv and pcDNA3.1-IP10-CDR3-PE40scfv plasmids which were proved by HindIII/EcoRI digestion. SKOV3 cells and HOSEpiC cells were incubated with fluorescein isothiocyanate (FITC) labeled IP10-CDR3scfv and IP10-CDR3-PE40scfv proteins and protein levels were examined by flow cytometry. After gene transfection, SKOV3 cells were divided into four groups: Control, pcDNA3.1(+) negative control (NC) (pcDNA3.1(+) NC transfection), IP10-CDR3scfv (IP10-CDR3scfv transfection) and IP10-CDR3-PE40scfv (IP10-CDR3-PE40scfv transfection). Levels of IP10, CDR3, Caspase-3, cleaved Caspase-3 and Bcl-2 were determined by RT-PCR and Western blot. Cell viability and apoptosis were investigated by CCK-8 assay and Annexin V-FITC/PI assay, respectively.

RESULTS

The levels of FITC-labeled IP10-CDR3scfv and IP10-CDR3-PE40scfv proteins in the SKOV3+IP10-CDR3scfv group and the SKOV3+IP10-CDR3-PE40scfv group were remarkably higher than that in the SKOV3 group (P<0.05). So was the HOSEpiC related groups. There was no obvious difference in the levels of IP10, CDR3, Caspase-3, cleaved Caspase-3 and Bcl-2 between the control group and the pcDNA3.1(+) NC group. However, compared with the control group, the levels of Caspase-3 and Bcl-2 were reduced notably and the levels of IP10, CDR3 and cleaved Caspase-3 were elevated sharply in the IP10-CDR3scfv and IP10-CDR3-PE40scfv groups (P<0.05). The control group and the pcDNA3.1(+) NC group demonstrated similar cell viability and apoptosis. However, compared with the control group, cell viability in the IP10-CDR3scfv and IP10-CDR3-PE40scfv groups decreased significantly and cell apoptosis increased (P<0.05).

CONCLUSION

IP10-CDR3 could reduce the viability and induce the apoptosis of ovarian cancer cells by down-regulating the expression of Bcl-2 and Caspase-3.

Monoclonal and oligoclonal TCR AV and BV gene usage in CD4+ T cells from pigs immunised with C-strain CSFV vaccine

The classical swine fever virus C-strain vaccine (C-strain vaccine) plays a vital role in preventing and controlling the spread of classical swine fever (CSF). However, the protective mechanisms of C-strain vaccine and cellular immunity conferred by T cell receptors (TCRs) are less well defined. We aimed to analyse the association between the complementarity determining region 3 (CDR3) spectratype of αβTCR in CD4⁺ T cells and C-strain vaccine; and to find conserved CDR3 amino acid motifs in specific TCR α- and β-chains. We found that the CDR3 spectratype showed dynamic changes correlating with C-strain vaccine immunisation and that TCR AV5S/8–3S/8–4S/14/38 and BV4S/6S/7S/15S/30 gene families showed clonal expansion in immunised pigs. The sequences of CDR3 from these clonally expanded T cells indicated a high frequency of the ‘KLX’ motif in the TCR α chain and the ‘GGX’ motif in β chain, and Jα39, Jα43, Jβ2.5 and Jβ2.3 genes were also found in high frequency. To the best of our knowledge, this is the first report describing the dynamic changes of αβTCRs and conserved CDR3 amino acid motifs in CD4⁺ T cells from C-strain vaccine-immunised pigs, which will provide a basis for the development of high-efficiency epitope vaccines.

Specific Adoptive T-Cell Therapy for Viral and Fungal Infections

Despite advances in anti-infective agents, viral and fungal infections after hematopoietic stem cell transplantation (HSCT) continue to cause life-threatening complications that limit the success of HSCT. Early adoptive T-cell immunotherapy studies showed that administration of allogeneic virus-specific cytotoxic T lymphocytes (vCTL) can prevent and control viral infections and reconstitute antiviral immunity to cytomegalovirus (CMV) and Epstein-Barr virus (EBV). Advances in immunobiology, in vitro culture technology, and current good manufacturing practice (cGMP) have provided opportunities for advancing adoptive cell therapy for viral infections: (1) T cells have been expanded targeting multiple pathogens; (2) vCTL production no longer requires viral infection or viral vector transduction of antigen-presenting cells (APCs); (3) the source of lymphocytes is no longer restricted to donors who are immune to the pathogens; (4) naive T cells have been redirected with chimeric antigen receptor T cells (CARTs) or armed with bispecific antibody-armed T cells (BATs) to mediate vCTL activity; (5) these technologies could be combined to targeted multiple viral or fungal pathogens; and (6) pathogen-specific T-cell products manufactured from third parties and banked for “off-the-shelf” use post-HSCT may soon become a reality.

Human CD8(+) T cells transduced with an additional receptor bispecific for both Mycobacterium tuberculosis and HIV-1 recognize both epitopes

Tuberculosis (TB) and human immunodeficiency virus type 1 (HIV-1) infection are closely intertwined, with one-quarter of TB/HIV coinfected deaths among people died of TB. Effector CD8(+) T cells play a crucial role in the control of Mycobacterium tuberculosis (MTB) and HIV-1 infection in coinfected patients. Adoptive transfer of a multitude of effector CD8(+) T cells is an appealing strategy to impose improved anti-MTB/HIV-1 activity onto coinfected individuals. Due to extensive existence of heterologous immunity, that is, T cells cross-reactive with peptides encoded by related or even very dissimilar pathogens, it is reasonable to find a single T cell receptor (TCR) recognizing both MTB and HIV-1 antigenic peptides. In this study, a single TCR specific for both MTB Ag85B199-207 peptide and HIV-1 Env120-128 peptide was screened out from peripheral blood mononuclear cells of a HLA-A*0201(+) healthy individual using complementarity determining region 3 spectratype analysis and transferred to primary CD8(+) T cells using a recombinant retroviral vector. The bispecificity of the TCR gene-modified CD8(+) T cells was demonstrated by elevated secretion of interferon-γ, tumour necrosis factor-α, granzyme B and specific cytolytic activity after antigen presentation of either Ag85B199-207 or Env120-128 by autologous dendritic cells. To the best of our knowledge, this study is the first report proposing to produce responses against two dissimilar antigenic peptides of MTB and HIV-1 simultaneously by transfecting CD8(+) T cells with a single TCR. Taken together, T cells transduced with the additional bispecific TCR might be a useful strategy in immunotherapy for MTB/HIV-1 coinfected individuals.

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

Introduction

The 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 methods

In 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.

Results

The 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.

Conclusions

This 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.

Molecular characterization of T cell receptor beta variable in the peripheral blood T cell repertoire in subjects with active tuberculosis or latent tuberculosis infection

Background

T cells are closely linked to the clinical manifestations of subjects with Mycobacterium tuberculosis (MTB) infection. T cell receptor beta variable (TCRBV) is a signal and indicative molecule on the membrane of T lymphocytes, reflecting the composition and specificity of T cells. The molecular profiles of TCRBV in peripheral blood mononuclear cells (PBMCs) and their subpopulations (CD4⁺ and CD8⁺ T cells) from subjects with active tuberculosis (TB) or latent TB infection (LTBI) have not been well described.

Methods

In 42 subjects with active TB or LTBI, PMBCs and their subsets were separated and sorted. The molecular profiles of the TCRBV complementarity determining region 3 (CDR3) in the three cell populations were investigated using our recently developed gene melting spectral pattern (GMSP) assay. The TCRBV members were then cloned and sequenced when their GMSP image profiles showed a single-peak.

Results

The average number of skewed TCRBV molecules in the CD4⁺ cell subset was significantly higher than that in PBMCs and CD8⁺ T cells. TCRBV12, BV13.1, BV13.2, and BV24 were expressed more prevalently than other TCRBV gene families in the three cell populations. In addition, relatively conserved amino acid motifs were identified in TCRBV5.1 and BV20 CDR3 in PBMCs and its subsets. The monoclonal TCRBV14 and BV23 expressed were different between active TB and LTBI subjects.

Conclusions

These results indicate that the T cell immune response is complex and multi-specific in active TB and LTBI subjects. Analysis of TCRBV expression in CD4⁺ T cells suggest that it could be useful in assessing the composition and status of circulating T cells. Furthermore, the expression of TCRBV14, BV23 and the sequencing of CDR3 amino acid motifs of TCRBV5.1, BV20 could be used in the differential diagnosis and treatment of subjects with active TB or LTBI.

Limited T cell receptor beta variable repertoire responses to ESAT-6 and CFP-10 in subjects infected with Mycobacterium tuberculosis

Mycobacterium tuberculosis (MTB)-specific antigens, ESAT-6 or CFP-10 play a key role in diagnosis and control MTB infection. T cell receptor (TCR) reflects the status and function of T cells. However, the features of the TCR beta variable (TCRBV) repertoire used against ESAT-6 and CFP-10 from MTB subjects have not been well described. The molecular profiles of TCRBV complementarity-determining region 3 (CDR3) in PBMCs with or without ESAT-6 or CFP-10 stimulation were assayed using a gene melting spectral pattern (GMSP) assay developed in our previous study. The average number of skewed TCRBV family in PBMCs stimulated with ESAT-6 or CFP-10 was significantly higher than that in unstimulated PBMCs. TCRBV3, BV5.1, BV12, BV13.1, BV13.2, BV20 and BV24 were used more frequently than other TCRBV members in PBMCs from MTB subjects, and TCRBV3, BV5.1 in stimulated PBMCs have a preference in the usage of variable (V) and joining (J) segments and CDR3. The results indicate that the T cell immune response in MTB subjects involves a few of specific T cells. The preferred usage of certain V and J segments and CDR3s of TCRBV3 or BV5.1 may be related to ESAT-6 or CFP-10 respectively, which would help clinical differential diagnosis and treatment of MTB-infected subjects.

Development of CD8+ T cells expressing two distinct receptors specific for MTB and HIV-1 peptides

The immune response in individuals co-infected with Mycobacterium tuberculosis (MTB) and the human immunodeficiency virus (MTB/HIV) gradually deteriorates, particularly in the cellular compartment. Adoptive transfer of functional effector T cells can confer protective immunity to immunodeficient MTB/HIV co-infected recipients. However, few such effector T cells exist in vivo, and their isolation and amplification to sufficient numbers is difficult. Therefore, enhancing immune responses against both pathogens is critical for treating MTB/HIV co-infected patients. One approach is adoptive transfer of T cell receptor (TCR) gene-modified T cells for the treatment of MTB/HIV co-infections because lymphocyte numbers and their functional avidity is significantly increased by TCR gene transfer. To generate bispecific CD8⁺ T cells, MTB Ag85B_199–207 peptide-specific TCRs (MTB/TCR) and HIV-1 Env_120–128 peptide-specific TCRs (HIV/TCR) were isolated and introduced into CD8⁺ T cells simultaneously using a retroviral vector. To avoid mispairing among exogenous and endogenous TCRs, and to improve the function and stability of the introduced TCRs, several strategies were employed, including introducing mutations in the MTB/TCR constant (C) regions, substituting part of the HIV/TCR C regions with CD3ζ, and linking gene segments with three different 2A peptides. Results presented in this report suggest that the engineered T cells possessed peptide-specific specificity resulting in cytokine production and cytotoxic activity. This is the first report describing the generation of engineered T cells specific for two different pathogens and provides new insights into TCR gene therapy for the treatment of immunocompromised MTB/HIV co-infected patients.

Limited T cell receptor repertoire diversity in tuberculosis patients correlates with clinical severity

Background

The importance of CD4⁺ and CD8⁺ T cells in protection against tuberculosis (TB) is well known, however, the association between changes to the T cell repertoire and disease presentation has never been analyzed. Characterization of T-cells in TB patients in previous study only analyzed the TCR β chain and omitted analysis of the Vα family even though α chain also contribute to antigen recognition. Furthermore, limited information is available regarding the heterogeneity compartment and overall function of the T cells in TB patients as well as the common TCR structural features of Mtb antigen specific T cells among the vast numbers of TB patients.

Methodology/Principal Findings

CDR3 spectratypes of CD4⁺ and CD8⁺ T cells were analyzed from 86 patients with TB exhibiting differing degrees of disease severity, and CDR3 spectratype complexity scoring system was used to characterize TCR repertoire diversity. TB patients with history of other chronic disease and other bacterial or viral infections were excluded for the study to decrease the likely contribution of TCRs specific to non-TB antigens as far as possible. Each patient was age-matched with a healthy donor group to control for age variability. Results showed that healthy controls had a normally diversified TCR repertoire while TB patients represented with restricted TCR repertoire. Patients with mild disease had the highest diversity of TCR repertoire while severely infected patients had the lowest, which suggest TCR repertoire diversity inversely correlates with disease severity. In addition, TB patients showed preferred usage of certain TCR types and have a bias in the usage of variable (V) and joining (J) gene segments and N nucleotide insertions.

Conclusions/Significance

Results from this study promote a better knowledge about the public characteristics of T cells among TB patients and provides new insight into the TCR repertoire associated with clinic presentation in TB patients.

Protective capacity of virus-specific T cell receptor-transduced CD8 T cells in vivo

The transfer of T cell receptor (TCR) genes by viral vectors represents a promising technique to generate antigen-specific T cells for adoptive immunotherapy. TCR-transduced T cells specific for infectious pathogens have been described, but their protective function in vivo has not yet been examined. Here, we demonstrate that CD8 T cells transduced with the P14 TCR specific for the gp33 epitope of lymphocytic choriomeningitis virus exhibit protective activities in both viral and bacterial infection models in mice.

How (specific) would like your T-cells today? Generating T-cell therapeutic function through TCR-gene transfer

T-cells are central players in the immune response against both pathogens and cancer. Their specificity is solely dictated by the T-cell receptor (TCR) they clonally express. As such, the genetic modification of T lymphocytes using pathogen- or cancer-specific TCRs represents an appealing strategy to generate a desired immune response from peripheral blood lymphocytes. Moreover, notable objective clinical responses were observed in terminally ill cancer patients treated with TCR-gene modified cells in several clinical trials conducted recently. Nevertheless, several key aspects of this approach are the object of intensive research aimed at improving the reliability and efficacy of this strategy. Herein, we will survey recent studies in the field of TCR-gene transfer dealing with the improvement of this approach and its application for the treatment of malignant, autoimmune, and infectious diseases.