Thymic Rejuvenation: Are We There Yet?

Vaccination is an appealing form of immunotherapy for frail senior patients. However, several studies have shown that in contrast to younger adults, older patients do not effectively respond to vaccines. This phenomenon is greatly attributed to immunosenescence, a hallmark of aging defined by a general decline in immunity caused by thymic involution. Historically, the study of thymic involution brought to attention several factors and components involved in thymopoiesis, as contributors to the phenomena. Depicting the underlying cause(s) of the dramatic changes in the production and properties of the naïve T-cell pool in the event of acute thymic injury or due to inovulation can therefore, help focus the efforts on the best strategy to reverse or overcome these hurdles. Here, we discuss some of the well-studied approaches for rejuvenating the thymus, and introduce interleukin-(IL) 21 as the most recent thymo-stimulatory agent in the field

A MCP1 fusokine with CCR2-specific tumoricidal activity

<p>Abstract</p> <p>Background</p> <p>The CCL2 chemokine is involved in promoting cancer angiogenesis, proliferation and metastasis by malignancies that express CCR2 receptor. Thus the CCL2/CCR2 axis is an attractive molecular target for anticancer drug development.</p> <p>Methods</p> <p>We have generated a novel fusion protein using GMCSF and an N-terminal truncated version of MCP1/CCL2 (6-76) [hereafter GMME1] and investigated its utility as a CCR2-specific tumoricidal agent.</p> <p>Results</p> <p>We found that distinct to full length CCL2 or its N-truncated derivative (CCL2 5-76), GMME1 bound to CCR2 on mouse lymphoma EG7, human multiple myeloma cell line U266, or murine and human medulloblastoma cell lines, and led to their death by apoptosis. We demonstrated that GMME1 specifically blocked CCR2-associated STAT3 phosphorylation and up-regulated pro-apoptotic BAX. Furthermore, GMME1 significantly inhibited EG7 tumor growth in C57BL/6 mice, and induced apoptosis of primary myeloma cells from patients.</p> <p>Conclusion</p> <p>Our data demonstrate that GMME1 is a fusokine with a potent, CCR2 receptor-mediated pro-apoptotic effect on tumor cells and could be exploited as a novel biological therapy for CCR2⁺malignancies including lymphoid and central nervous system malignancies.</p

Fusokine design as novel therapeutic strategy for immunosuppression

The societal burden of autoimmune diseases and donor organ transplant rejection in developed countries reflects the lack of effective immune suppressive drugs. The main objective of my thesis was to develop novel fusion proteins targeting receptors linked to autoimmunity; strategies that will allow the suppression of autoreactive cells while sparing resting lymphocytes. Interleukin (IL) 15 has been demonstrated to exert its effects mainly on activated T-cells triggered via their T-cell receptor (TCR). Since we found that the fusion of granulocyte-macrophage colony stimulating factor (GMCSF) to IL15 - aka GIFT15 - paradoxically leads to aberrant signalling downstream of the IL15R and blocks interferon (IFN)-gamma secretion in a mixed lymphocyte reaction (MLR), we hypothesized to use this fusokine in proof-of-principle cell transplantation models and shown that GIFT15 can indeed block the rejection of allogeneic and xenogeneic cells in immunocompetent mice. Additionally, we found that ex vivo GIFT15 treatment of mouse splenocytes lead to the generation of regulatory B-cells (Bregs). These Bregs express high levels of MHCII, IL10 and are capable to block antigen (Ag)-presentation in vitro as third party bystander cells. Moreover, a single injection of these GIFT15-generated Bregs in mice with pre-developed experimental autoimmune encephalomyelitis (EAE) leads to long lasting remission of disease.Along those lines, we also found that mesenchymal stromal cells (MSCs) lead to the paracrine conversion of CCL2 to an antagonist form capable of specifically inhibiting plasma cells and activated Th17 cells. This mechanistic insight informed the design of a second class of suppression fusokine. Namely, the fusing of antagonist CCL2 to GMCSF - aka GMME1. We tested its potential use in autoimmune diseases such as EAE and rheumatoid arthritis (RA). We demonstrated that GMME1 leads to asymmetrical signalling and inhibition of plasma cells as well as Th17 EAE/RA-reactive CD4 T-cells. The net outcome of these pharmacological effects is the selective depletion of CCR2-reactive T-cells as demonstrated both in vitro and in vivo.Overall, our data support the use of our fusion proteins as part of a powerful and specific immunosuppressive strategy either as directly injectable protein biopharmaceuticals or through the ex vivo generation of autologous Bregs in the case of GIFT15

Accum&trade; Technology: A Novel Conjugable Primer for Onco-Immunotherapy

Compromised activity is a common impediment for biologics requiring endosome trafficking into target cells. In cancer cells, antibody-drug conjugates (ADCs) are trapped in endosomes or subsequently pumped extracellularly, leading to a reduction in intracellular accumulation. In subsets of dendritic cells (DCs), endosome-engulfed antigens face non-specific proteolysis and collateral damage to epitope immunogenicity before proteasomal processing and subsequent surface presentation. To bypass these shortcomings, we devised Accum&trade;, a conjugable biotechnology harboring cholic acid (ChAc) and a nuclear localization signal (NLS) sequence for endosome escape and prompt nuclear targeting. Combined, these mechanisms culminate in enhanced intracellular accumulation and functionalization of coupled biologics. As proof-of-principle, we have biochemically characterized Accum, demonstrating its adaptability to ADCs or antigens in different cancer settings. Additionally, we have validated that endosome escape and nuclear routing are indispensable for effective intracellular accumulation and guaranteed target cell selectivity. Importantly, we have demonstrated that the unique mechanism of action of Accum translates into enhanced tumor cytotoxicity when coupled to ADCs, and durable therapeutic and prophylactic anti-cancer immunogenicity when coupled to tumor antigens. As more pre-clinical evidence accumulates, the adaptability, unique mechanism of action, and high therapeutic potency of Accum signal a promising transition into clinical investigations in the context of onco-immunotherapy

Bone marrow aspirate concentrate versus platelet-rich plasma for treating knee osteoarthritis: a one-year non-randomized retrospective comparative study

Abstract Background Knee osteoarthritis (OA) is a debilitating condition affecting human body biomechanics and quality of life. Current standard care for knee OA leads to trivial improvement and entails multiple adverse effects or complications. Recently, investigational cell therapies injected intra-articularly, such as bone marrow aspirate concentrate (BMAC) and platelet-rich plasma (PRP), have shown safety and therapeutic potency providing patients with pain relief. In the current retrospective comparative study, we investigated the differences in pain and functional improvements in patients with symptomatic knee OA receiving intra-articular injections of BMAC vs PRP. Methods Pain and functionality scores were measured at baseline and at different time points post-injection over 12 months, using 3 self-administered, clinically validated questionnaires: the visual analogue scale (VAS) for assessing pain intensity, the knee injury and osteoarthritis outcome score (KOOS) for evaluating functionality and knee-related quality of life, and the Western Ontario and McMaster Universities Arthritis Index (WOMAC) for evaluating physical function. The repeated-measures general linear model with Sidak test for pairwise comparisons was used to investigate the influence of the treatment on the score evolution within groups (between baseline and each time point) and between groups (overall). Results The BMAC group (n = 26 knees) significantly improved in VAS, KOOS, and WOMAC scores between baseline and 12 months (57.4, 75.88, and 73.95% mean score improvement, respectively). In contrast, the PRP group (n = 13 knees) witnessed nonsignificant improvement in all scores. BMAC, in comparison to PRP, induced significant improvement in outcomes by 29.38% on the VAS scale, 53.89% on the KOOS scale, and 51.71% on the WOMAC scale (P < .002, P < .01, P < .011, respectively). Conclusions Intra-articular autologous BMAC injections are safe, effective in treating pain, and ameliorate functionality in patients with symptomatic knee OA to a greater extent than PRP injections. Graphical abstract Intra-articular autologous BMAC therapy is safe and provides more relief to patients with symptomatic knee osteoarthritis compared to PRP therapy

Analysis of TCR diversity.

<p>A–B) Flow-cytometry analysis of 15 TCRVβ-chains using intrathymic CD4 (A) or CD8 (B) SP T cells. C–D) Similar flow-cytometry analyses were performed using spleen CD4 (A) or CD8 (B) SP T cells. For both analyses, T cells were derived from PBS- (dark blue), DEX/PBS- (blue) or DEX/rIL-21-treated mice (light blue). We tested 3 mice per group. Data shown are representative of 3 separate experiments.</p