No abstract

Clinical translation of cell therapies requires strategies that can manufacture cells efficiently and economically. One promising way to reproducibly expand T cells for cancer therapy is by attaching the stimuli for T cells onto artificial substrates with high surface area. Here, we show that a carbon nanotube-polymer composite can act as an artificial antigen-presenting cell to efficiently expand the number of T cells isolated from mice. We attach antigens onto bundled carbon nanotubes and combined this complex with polymer nanoparticles containing magnetite and the T-cell growth factor interleukin-2 (IL-2). The number of T cells obtained was comparable to clinical standards using a thousand-fold less soluble IL-2. T cells obtained from this expansion were able to delay tumour growth in a murine model for melanoma. Our results show that this composite is a useful platform for generating large numbers of cytotoxic T cells for cancer immunotherapy.

Objective To explore the role of immune dysregulation in antibiotic-refractory Lyme arthritis, the phenotype, frequency and function of CD4+ Teff and Treg cells were compared in patients with antibiotic-responsive or antibiotic-refractory arthritis. In the latter condition, infection-induced autoimmunity is thought to have a pathogenic role. Methods Matched peripheral blood (PB) and synovial fluid (SF) samples from 15 patients with antibiotic-responsive arthritis were compared with those from 16 patients with antibiotic-refractory arthritis using flow cytometry, suppression and cytokine assays. Results Critical differences between the 2 patient groups were found in the SF CD4+CD25hi+ populations, a subset of cells usually composed of FOXP3-positive Treg cells. In patients with antibiotic-refractory arthritis, this cell population often had fewer FOXP3-positive cells, and greater frequencies of FOXP3-negative (Teff) compared to patients with antibiotic-responsive arthritis. Moreover, in the refractory group, CD4+CD25hi+ cells had significantly greater expression of GITR and OX-40, two co-receptors that augment T cell function. Suppression assays showed that CD4+CD25hi+ cells in patients with refractory arthritis did not effectively suppress proliferation of CD4+CD25− cells, or secretion of IFN-γ or TNF-α, whereas those from patients with responsive arthritis did. Finally, in the refractory group, higher ratios of CD25hi+FOXP3−/CD25hi+FOXP3+ cells correlated directly with longer post-treatment durations of arthritis. Conclusion Patients with antibiotic-refractory Lyme arthritis often had lower frequencies of Treg, higher expression of activation co-receptors, and less effective inhibition of pro-inflammatory cytokines. This suggests that immune responses in these patients were excessively amplified leading to immune dysregulation and refractory arthritis.

The mechanisms whereby immune therapies affect progression of Type 1 diabetes (T1D) are not well understood. Teplizumab, an FcR non-binding anti-CD3 mAb, has shown efficacy in multiple randomized clinical trials. We previously reported an increase in the frequency of circulating CD8+ central memory (CD8CM) T cells in clinical responders, but the generalizability of this finding and the molecular effects of teplizumab on these T cells have not been evaluated. We analyzed data from 2 randomized clinical studies of teplizumab in patients with new and recent onset T1D. At the conclusion of therapy clinical responders showed a significant reduction in circulating CD4+ effector memory (CD4EM) T cells. Afterwards, there was an increase in the frequency and absolute number of CD8CM T cells. In vitro, teplizumab expanded CD8CM T cells by proliferation and conversion of non-CM T cells. Nanostring analysis of gene expression of CD8CM T cells from responders and non-responders vs placebo-treated control subjects identified decreases in expression of genes associated with immune activation and increases in expression of genes associated with T cell differentiation and regulation. We conclude that CD8CM T cells with decreased activation and regulatory gene expression are associated with clinical responses to teplizumab in patients with T1D.

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Alternative splicing results in multiple protein isoforms derived from a single gene. The magnitude of this process ranges from a complete loss of function to gain of new function. We examined, as a paradigm, alternative splicing of the non-redundant human cytokine, interleukin-7 (IL-7). We show that extensive IL-7 splicing in human tissues of different histology, including MTB þ granuloma lesions, transformed tissue and tumor cell lines. IL-7 splice variants were expressed as recombinant proteins. A differentially spliced IL-7 isoform, lacking exon 5, leads to STAT-5 phosphorylation in CD4 þ and CD8 þ T cells, promotes thymocyte maturation and T-cell survival. Human tumor lesions show aberrant IL-7 isoform expression, as compared with the autologous, non-transformed tissue. Alternatively spliced cytokines, such as IL-7, represent candidates for diagnostics and therapeutic interventions.

Alternative splicing of pre-mRNA increases proteomic diversity, a crucial mechanism in defining tissue identity. We demonstrate differentially spliced interleukin (IL)-7 in distinct anatomic areas in the adult, in developing human brains and in normal human neuronal progenitor (NHNP) cells. IL-7c (c, the canonical form spanning all six exons) or its variants IL-7d5, d4 or d4/5 were cloned and expressed as recombinant proteins. IL-7 and splice variants were able to shift the differentiation of NHNP cells as compared with the diluent control (Po0.01) defined by anti-b (III)-tubulin and glial fibrillary acidic protein expression, with different degrees (IL-7c4d4/54IL-7d5); IL-7d4 exhibited a significantly weaker potency. Differentiation was confirmed by transcriptome analysis of IL-7c-stimulated neural NHNP cells, resulting in 58 differentially expressed genes; some of these are involved in neural differentiation, for example, the developmentally regulated transcription factor krü ppel-like factor 12, musashi 2, a translational regulator of cell fate or the sonic hedgehog receptor patch 1. This suggests that IL-7 influences neural development at a molecular level by participating in human brain architecture through glia cell formation: a paradigm that alternative splicing in cytokines, for example, for IL-7, has a physiological role in human organ development and progenitor cell differentiation.

Interleukin‐7‐receptor‐signaling plays a pivotal role in T‐cell development and maintenance of T‐cell memory. We studied IL‐7Rα (CD127) expression in PBMCs obtained from patients with breast cancer and examined IL‐7 receptor‐mediated downstream effects defined by STAT5 phosphorylation (p‐STAT5). Reduced numbers of IL‐7Rα‐positive cells were identified in CD4+ T‐cells as well as in a CD8+ T‐cell subset defined by CD8α/α homodimer expression in patients with breast cancer. PBMCs obtained from healthy donors (n = 19) and from patients with breast cancer (n = 19) exhibited constitutive p‐STAT5 expression in the range of 0–6.4% in CD4+ T‐cells and 0–4% in CD8+ T‐cells. Stimulation with recombinant human IL‐7 for 15 min increased p‐STAT5 expression up to 36–97% in CD4+T‐cells and to 26–90% in CD8+T‐cells obtained from healthy control donors (n = 19). In contrast, PBMCs obtained from 13/19 patients with breast cancer did not respond to IL‐7 as defined by STAT5 phosphorylation, despite expression of IL‐7Rα on T‐lymphocytes. T‐cells were further characterized for IL‐ 2 and IFN‐γ production induced by PMA/Ionomycin. PBMCs from 9/19 patients with breast cancer showed decreased IL‐2 and IFN‐γ production combined with IL‐7‐signaling defects; PBMCs from 4 patients with breast cancer exhibited deficient IL‐7‐signaling, yet intact cytokine production. Reduced numbers of IL‐7Rα‐positive cells and nonresponsiveness to IL‐7, defined by lack of STAT5 phosphorylation, characterizes the immunological profile in T‐cells from patients with breast cancer. © 2007 Wiley‐Liss, Inc.