Combined CD28 and 4-1BB Costimulation Potentiates Affinity-tuned Chimeric Antigen Receptor-engineered T Cells

Purpose: Targeting nonspecific, tumor-associated antigens (TAA) with chimeric antigen receptors (CAR) requires specific attention to restrict possible detrimental on-target/off-tumor effects. A reduced affinity may direct CAR-engineered T (CART) cells to tumor cells expressing high TAA levels while sparing low expressing normal tissues. However, decreasing the affinity of the CAR-target binding may compromise the overall antitumor effects. Here, we demonstrate the prime importance of the type of intracellular signaling on the function of lowaffinity CAR-T cells. Experimental Design: We used a series of single-chain variable fragments (scFv) with five different affinities targeting the same epitope of the multiple myeloma-associated CD38 antigen. The scFvs were incorporated in three different CAR costimulation designs and we evaluated the antitumor functionality and off-tumor toxicity of the generated CAR-T cells in vitro and in vivo. Results: We show that the inferior cytotoxicity and cytokine secretion mediated by CD38 CARs of very low-affinity (K d < 1.9 × 10 -6 mol/L) bearing a 4-1BB intracellular domain can be significantly improved when a CD28 costimulatory domain is used. Additional 4-1BB signaling mediated by the coexpression of 4-1BBL provided the CD28-based CD38 CAR-T cells with superior proliferative capacity, preservation of a central memory phenotype, and significantly improved in vivo antitumor function, while preserving their ability to discriminate target antigen density. Conclusions: A combinatorial costimulatory design allows the use of very low-affinity binding domains (K d < 1 mmol/L) for the construction of safe but also optimally effective CAR-T cells. Thus, very-low-affinity scFvs empowered by selected costimulatory elements can enhance the clinical potential of TAA-targeting CARs

Malaria Parasite-Mediated Alteration of Macrophage Function and Increased Iron Availability Predispose to Disseminated Nontyphoidal Salmonella Infection.

Disseminated infections with nontyphoidal Salmonella (NTS) are a significant cause of child mortality in sub-Saharan Africa. NTS infection in children is clinically associated with malaria, suggesting that malaria compromises the control of disseminated NTS infection. To study the mechanistic basis for increased NTS susceptibility, we utilized a model of concurrent infection with Salmonella enterica serotype Typhimurium and Plasmodium yoelii nigeriensis (P. yoelii). Underlying malaria blunted monocyte expression of Ly6C, a marker for inflammatory activation, and impaired recruitment of inflammatory cells to the liver. Hepatic mononuclear phagocytes expressed lower levels of inducible nitric oxide synthase, tumor necrosis factor alpha, and granulocyte-macrophage colony-stimulating factor and showed increased levels of production of interleukin-10 and heme oxygenase-1, indicating that the underlying malaria modifies the activation state and inflammatory response of mononuclear phagocytes to NTS. P. yoelii infection also increased intracellular iron levels in liver mononuclear cells, as evidenced by elevated levels of ferritin and by the rescue of an S Typhimurium tonB feoB mutant defective for iron uptake. In addition, concurrent P. yoelii infection partially rescued the systemic colonization defect of an S Typhimurium spiB mutant defective for type III secretion system 2 (T3SS-2), indicating that the ability of phagocytic cells to limit the spread of S Typhimurium is impaired during concurrent P. yoelii infection. These results show that concurrent malaria increases susceptibility to disseminated NTS infection by blunting macrophage bactericidal mechanisms and providing an essential nutrient that enhances bacterial growth

L'acide pipemidique dans la prophylaxie des cystites récidivantes chez la femme

SCOPUS: NotDefined.jinfo:eu-repo/semantics/publishe

Preclinical evaluation of invariant natural killer t cells modified with cd38 or bcma chimeric antigen receptors for multiple myeloma

Due to the CD1d restricted recognition of altered glycolipids, Vα24-invariant natural killer T (iNKT) cells are excellent tools for cancer immunotherapy with a significantly reduced risk for graft-versus-host disease when applied as off-the shelf-therapeutics across Human Leukocyte Antigen (HLA) barriers. To maximally harness their therapeutic potential for multiple myeloma (MM) treatment, we here armed iNKT cells with chimeric antigen receptors (CAR) directed against the MM-associated antigen CD38 and the plasma cell specific B cell maturation antigen (BCMA). We demonstrate that both CD38-and BCMA-CAR iNKT cells effectively eliminated MM cells in a CAR-dependent manner, without losing their T cell receptor (TCR)-mediated cytotoxic activity. Importantly, iNKT cells expressing either BCMA-CARs or affinity-optimized CD38-CARs spared nor-mal hematopoietic cells and displayed a Th1-like cytokine profile, indicating their therapeutic util-ity. While the costimulatory domain of CD38-CARs had no influence on the cytotoxic functions of iNKT cells, CARs containing the 4-1BB domain showed a better expansion capacity. Interestingly, when stimulated only via CD1d+ dendritic cells (DCs) loaded with α-galactosylceramide (α-GalCer), both CD38-and BCMA-CAR iNKT cells expanded well, without losing their CAR-or TCR-dependent cytotoxic activities. This suggests the possibility of developing an off-the-shelf therapy with CAR iNKT cells, which might even be boostable in vivo by administration α-GalCer pulsed DCs

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Off-tumor effect of inducible CD38-CAR T cells.

<p>(A) Representative flow cytometry density plots of MM-BM with CD38⁺/CD138⁺ cells (MM) after treatment with inducible mock (+/- 1000 ng/ml DOX for 48 hours) and inducible high affinity (028) CD38-CAR T cells (- DOX or + 1000 ng/ml DOX for 48 hours and 0, 24 or 120 hours after DOX removal). (B) Pooled data obtained from the analysis of five MM patient bone marrow samples (patient 1–5, see for their phenotype data <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0197349#pone.0197349.s004" target="_blank">S4 Fig</a>) with ~20% MM cells (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0197349#pone.0197349.s004" target="_blank">S4 Fig</a>) were co-incubated with inducible high affinity (028) CD38-CAR T cells (E:T ratio 3:1) treated with DOX according to the schedule <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0197349#pone.0197349.g003" target="_blank">Fig 3A</a>. Shown are the mean CAR-dependent % lysis of MM (CD138⁺/CD38⁺ ; open squares) and % lysis of healthy non-MM cells (CD138^-/CD56^-/CD38^+/-; grey diamonds) by inducible CD38-CAR T cells. Incubated with DOX for 24 hours 1000 ng/ml (upper left), 48 hours 1000 ng/ml (upper right), 24 hours 10 ng/ml (lower left), 48 hours 10 ng/ml (lower right). Presented is the pooled data from 5 independent experiments. Error bars indicate the mean +/- SEM. (Pt 1–5, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0197349#pone.0197349.s004" target="_blank">S4 Fig</a>).</p

Induction and decay kinetics of CD38-CAR expression.

<p>(A) schematic overview of CAR induction and decay assay. Black bars indicate the DOX incubation times, gray bars indicate the period of decay after the removal of DOX. (B and C) Representative results of five independent experiments of mean fluorescent intensity (MFI) of the CAR measured by staining with soluble his-tagged CD38 after 6, 24 or 48 hours incubation with (B) 10 or 1000 ng/ml DOX or 6, 24, 48 or 120 hours after washing of DOX (C) (an MFI of 600, observed by Mock cells was considered background expression). (D) A MM patient bone marrow sample with 20% MM cells was co-incubated with inducible, high affinity (028), CD38-CAR T cells (E:T ratio 3:1) treated with DOX according to the schedule depicted in Fig 3A. are the CAR-dependent % lysis of CD138+/CD38+ MM cells (% lysed by CAR—% lysed by Mock). Presented is the representative data of n = 5. (E) Significant Pearson correlation of MFI of CAR expression as detected with soluble CD38 (sCD38) with % lysis of MM cells. High dose DOX R² = 0.60 and p = 0.012, low dose DOX R² = 0.61 and p = 0.015.</p

Off-tumor effect of inducible low affinity CD38-CAR T cells.

<p>MM patient bone marrow samples (n = 4) with ~20% MM cells were co-incubated with inducible low affinity (B1) CD38-CAR T cells (E:T ratio 3:1) treated with DOX according to the schedule <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0197349#pone.0197349.g003" target="_blank">Fig 3A</a>. Depicted are the average CAR-dependent lysis of MM cells (CD138⁺/CD38⁺ ; open squares) and lysis of healthy non-MM cells (CD138^-/CD56^-/CD38^+/- ; grey diamonds) by inducible CD38-CAR T cells. Incubated with DOX for 24 hours 1000 ng/ml (upper left), 48 hours 1000 ng/ml (upper right), 24 hours 10 ng/ml (lower left), 48 hours 10 ng/ml (lower right). Presented is the pooled data from 4 independent experiments. Error bars indicate the mean +/- SEM. (Pt 2–5, same pts as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0197349#pone.0197349.g004" target="_blank">Fig 4</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0197349#pone.0197349.s004" target="_blank">S4 Fig</a>).</p

DOX dose-dependent induction of CD38-CAR expression and anti-MM cytotoxicity.

<p>(A) Lysis of luciferase-transduced CD38⁺ MM cell lines UM9 and RPMI8226 after co-incubation with Mock and inducible, high affinity (028) CD38-CAR, after treatment with no or 1000 ng/ml DOX for 48 hours. Grey lines indicate the lysis by constitutively expressed high affinity (028) CD38-CAR T cells The BLI signal from surviving MM cells was measured after 16 hours using a luminometer and the percentage lysis was calculated as indicated in the material & methods. Presented is the pooled data from 2 independent experiments. Error bars indicate the mean +/- SD (B) Mean fluorescent intensity (MFI) of the CAR measured by staining with soluble CD38-his after 48 hours incubation with 0, 1, 10, 100 or 1000 ng/ml DOX, Presented is the pooled data from 2 independent experiments. Error bars indicate the mean +/- SD. (C) The cytotoxic activity of untreated or DOX treated inducible CD38-CAR T cells against luc+ MM cell line UM9 after 16 hours. Presented is the pooled data from 2 independent experiments. Error bars indicate the mean +/- SD. In all panels * indicates p value <0.05 and ** <0.01 using one-way analysis of variance and subsequent multiple comparison.</p

DOX induced CD38-CAR expression.

<p>(A) Schematic overview of constructs. The pRetroX-TRE3G vector with the P_TRE3GV inducible promoter controlling the transcription of Mock containing the marker LNGFR or the CD38-CAR (shown is high affinity scFv 028; the same vector design is also used for low affinity CARs A4 and B1), consisting of the single chain variable fragments, 4-1BB and CD3ζ and a LNGFR separated by a P2A sequence. These vectors were co-transduced with the pRetroX-TET-On 3G containing the transcription site for the transactivator protein rTta. (B) Representative flow cytometry density plots and histograms to determine CAR expression of the inducible CAR T cells, after 48 hours incubation with 0 or 1000 ng/ml DOX. The expression of the marker LNGFR was measured with an APC-conjugated antibody. CAR expression was measured by binding of his-tagged (HHHHHH) soluble CD38 (sCD38) protein to the ScFv domain, stained with PE-conjugated anti-His tag antibody.</p