T cells expressing CD26-specific chimeric antigen receptors exhibit extensive self-antigen-driven fratricide

Abstract

Background: Immunotherapy utilizing T cells genetically modified to express chimeric antigen receptors (CARs) is rapidly emerging as a promising novel treatment for hematological and nonhematological malignancies. In order to target the TKI-insensitive leukemia stem cells (LSCs) in chronic myeloid leukemia (CML) by CAR T cells, we chose CD26 as a cell surface tumor-associated antigen due to preferentially expression on LSCs. Additionally, CD26 has also been suggested to be a multipurpose therapeutic target for other cancer. Therefore, developing the CD26-targeting CAR T cells may be a promising therapy for not only LSCs but also other CD26+ cancer cells.

Methods: We designed the second-generation CD26-targeting CAR utilizing 4-1BB (CD137) as costimulatory domain, and transduced T cells with CD26-CAR containing lentiviral. Then we evaluated the transduction efficiency and expansion ability, and demonstrated the existence of self-antigen-driven fratricide by cytokine assay and cytotoxicity assay.

Results: Anti-CD26-4-1BB-CAR T cells exhibited poor viability, multiple cytokine secretion, down-regulation of CD26 and direct cytotoxicity against themselves, indicating self-antigen-driven fratricide.

Conclusion: Eradicating CML-LSCs via anti-CD26-4-1BB-CAR T cells is not applicable, and optimized design or alternative target is needed.     

Identification of a founder mutation for Pendred syndrome in families from northwest Iran

ObjectiveMutations in the SLC26A4 gene cause both Pendred syndrome and autosomal recessive nonsyndromic hearing loss (ARNSHL) at the DFNB4 locus. The SLC26A4 mutations vary among different communities. Previous studies have shown that mutations in the SLC26A4 gene are responsible for the more common syndromic hereditary hearing loss in Iran. This study assesses the possibility of a founder mutation for Pendred syndrome in northwest Iran.Materials and methodsIn this study, we performed comprehensive clinical and genetic evaluations in two unrelated families from northwest Iran with nine members affected by hearing loss (HL). After testing short tandem repeat (STR) markers to confirm linkage to the SLC26A4 locus, we screened the SLC26A4 gene by Sanger sequencing of all 21 exons, exon–intron boundaries and the promoter region for any causative mutation. We identified the same causative mutation in these two families as we had detected earlier in two other Azeri families from northwest Iran. To investigate the possibility of a founder effect in these four families, we conducted haplotype analysis, and 14 single nucleotide polymorphisms (SNPs) throughout the SLC26A4 gene were genotyped.ResultsPatients in the two families showed the phenotype of Pendred syndrome. A known frameshift mutation (c.965insA, p.N322Fs7X) in exon 8 was identified in the two families, which was the same mutation that we detected previously in two other Azeri families. The results of haplotype analysis showed that all 15 patients from four families shared the founder mutation. Common haplotypes were not observed in noncarrier members.ConclusionsBased on the results of our two studies, the c.965insA mutation has only been described in Iranian families from northwest Iran, so there is evidence for a founder mutation originating in this part of Iran.     

Alcohol Modulation of Human Normal T-Cell Activation, Maturation, and Migration

We are interested in the characterization of the effects of alcohol on human T-cell activation, maturation, and migration, because this cell population is crucial in the initiation, regulation, and propagation of cellular immunity. We and others have described the effects of both acute and chronic exposure of human immune cells to ethanol (EtOH) in vitro. Herein, we briefly, review these reports and expand this body of literature with the inclusion of new data recently obtained in our laboratory. We confirm the blunting effects of EtOH on the production of interleukin-2 and mitogen proliferative response following T-cell mitogen stimulation, and on the expression of membrane markers of activation. We show that EtOH significantly alters the expression of the CD4 cell-associated marker of activation, CD26. We report the effect of EtOH on the expression of the homing receptor CD62L by CD4⁺ cells, and on their ability to adhere by a CD18-mediated process to a defined cellular substratum. Furthermore, we demonstrate the effects of EtOH and EtOH and 0-endor-phin pretreatment on the activation of CD4⁺ lymphocytes endowed with the homing receptor CD62L.     

Begelomab for severe refractory dermatomyositis: A case report

Rationale:Severe refractory idiopathic inflammatory myopathy (IIM) represents a challenge for the clinician. The lack of efficacy of available tools reflects our incomplete insight into the molecular events sustaining the inflammatory tissue damage in these patients. We present the first case of refractory IIM treated with anti-dipeptidyl peptidase-4 (DPP-4)/cluster of differentiation 26 (CD26) monoclonal antibody.Patient concerns:A 55-year old man presented with proximal muscle weakness, diffuse erythematous skin lesions which rapidly evolved into ulcerations, dysphagia and dysphonia.Diagnosis:Increased serum creatine kinase levels and histological findings at muscle and skin biopsies were compatible with the diagnosis of dermatomyositis (DM). Several lines of treatment failed to control the disease including steroids, mycophenolate mofetil, tacrolimus, intravenous immunoglobulins and rituximab. Despite therapy, the patient also had recurrent intestinal vasculitis causing bowel perforation. Concurrently, DPP-4/CD26 expression in the patient''s skin and skeletal muscle was observed.Interventions:The patient was treated with begelomab, a murine immunoglobulin G2b monoclonal antibody against DPP-4/CD26.Outcomes:Dysphagia, skin lesions and intestinal vasculitis resolved and the patient experienced a significant improvement of his quality of life.Conclusion:Blockade of DPP-4/CD26, which is expressed on T cells and mediates T cell activation and function, is safe and might be effective in patients with refractory DM.     

Double labelling of human umbilical cord mesenchymal stem cells with Gd‐DTPA and PKH26 and the influence on biological characteristics of hUCMSCs

The aim of this study was to determine whether double labelling of human umbilical cord mesenchymal stem cells (hUCMSCs) with gadolinium‐diethylene triamine penta‐acetic acid (Gd‐DTPA) and PKH26 influences their biological characteristics. A tissue adherence technique was used to separate and purify the hUCMSCs and flow cytometry was performed to detect the surface markers expressed on them. Gd‐DTPA and PKH26 were used to label the stem cells and MRI and fluorescence microscopy were used to detect the double‐labelled hUCMSCs. A MTT assay was used to delineate the growth curve. Transmission electron microscopy (TEM) and atomic force microscopy were used to demonstrate the ultrastructural features of the hUCMSCs. Flow cytometry showed that hUCMSCs highly expressed CD29, CD90, CD44 and CD105. No expression of CD31, CD34 and CD45 was detected. Very low expression of HLA‐DR and CD40 was detected. Atomic force microscopy showed these cells were long, spindle shaped, and the cytoplasm and nucleus had clear boundaries. After double labelling, TEM showed Gd particles aggregated in the cytoplasm in a cluster pattern. The proliferation activity, cell cycle, apoptosis and differentiation of the stem cells were not influenced by double labelling. Thus a tissue adherence technique is helpful to separate and purify hUCMSCs effectively; and Gd‐DTPA and PKH26 are promising tracers in the investigation of migration and distribution of hUCMSCs in vivo.