Immunology

ENGINEERING A SINGLE CHAIN ANTIBODY-BASED BIOLOGIC ARMED WTH AN APOPTOTIC EXECUTOR

by Scott Tarone

Published in 'Technological Innovations in Life Sciences'

Tumor specific antigens (TSAs) escape detection, thus allowing the tumor to grow unimpeded. The authors of this... more Tumor specific antigens (TSAs) escape detection, thus allowing the tumor to grow unimpeded. The authors of this article propose that TSA targeted therapeutics are within reach and will be: (i) able to penetrate cells via a universal entry point; (ii) able to specifically bind to a TSA; and (iii) in response to the binding event trigger a cellular response, preferably leading to the death of the tumor cell. From an engineering standpoint, the authors argue that this can be accomplished by assembling three components in a logical way such that the detection of a Tumor Specific Antigen within a cell leads to the induction of a desired downstream event; apoptosis.

Cholinergic signalling in gut immunity

by Shobhit Dhawan

Life Sciences

The gut immune system shares many signalling molecules and receptors with the autonomic nervous system. A good example... more The gut immune system shares many signalling molecules and receptors with the autonomic nervous system. A good example is the vagal neurotransmitter acetylcholine (ACh), for which many immune cell types express cholinergic receptors (AChR). In the last decade the vagal nerve has emerged as an integral part of an immune-regulation network via its release of ACh; a system coined “the cholinergic anti-inflammatory reflex”. The perspective of cholinergic immune regulation in the gut mucosa has been widened by the recent discovery of populations of ACh producing immune cells in the spleen and other organs. As such, ACh, classically referred to as neurotransmitter, may serve a much broader function as bi-directional signalling molecule between neurons and non-neuronal cell types of the immune system.

SUPPORT FOR THE IMMUNOCOMPETENCE HANDICAP HYPOTHESIS IN THE WILD: HORMONAL MANIPULATION DECREASES SURVIVAL IN SICK DAMSELFLIES

by Roberto Munguia-Steyer

Daniel M. González-Tokman, Roberto Munguía-Steyer, Isaac González-Santoyo, Fernanda S. Baena-Díaz, Alex Córdoba-Aguilar. Evolution. DOI: 10.1111/j.1558-5646.2012.01678.x

The immunocompetence handicap hypothesis (ICHH) states that hormones enhance sexual trait expression but impair... more The immunocompetence handicap hypothesis (ICHH) states that hormones enhance sexual trait expression but impair immunity. Previous tests of the ICHH have been hampered by experimental design problems. Here we report on an experimental test of the ICHH that includes manipulations of both hormones and infections in males of the territorial damselfly, Hetaerina americana, with accurate survival measurements. We conducted a fully factorial experiment subjecting each individual to one of three topical treatments: methoprene (a juvenile hormone analog), acetone, or control, and one of three injection treatments: bacteria, PBS, or control. We measured survival of manipulated males in both the wild and in captivity. As predicted, survival was most heavily impaired in methoprene-bacteria males than in the other groups in the wild, and no survival differences emerged in captive animals. This result confirms that survival is one cost an animal pays for increased hormonal levels. This corroborates theoretical predictions of the ICHH.

Intracellular IL-10 detection in T cells by flowcytometry: The use of protein transport inhibitors revisited

by Joost Smolders

Anne-Hilde Muris, Jan Damoiseaux, Joost Smolders, Jan Willem Cohen Tervaert, Raymond Hupperts, Mariëlle Thewissen. Journal of Immunological Methods 2012.

In the past two decades, interleukin-10 (IL-10) has gained much attention as an important regulatory cytokine involved... more In the past two decades, interleukin-10 (IL-10) has gained much attention as an important regulatory cytokine involved in self-tolerance. Functional assessment of IL-10 producing immune cells is traditionally done by stimulation and measurement of cytokine production by flowcytometry. Thereby a protein transport inhibitor like monensin is used to accumulate the cytokine of interest intracellularly. In this study we elaborated on the monensin effect on cytokine detection and focused on IL-10 detection in human T cells.

Peripheral blood mononuclear cells (PBMC) of 32 study subjects were isolated and stimulated with PMA/ionomycin, in the absence and presence of monensin, and stained intracellularly for IFN-γ, IL-4, IL-10 and IL-17A.

Our results re-established that detection of IFN-γ+ and IL-4+ T cells benefited from the presence of monensin during stimulation. However, stimulation in the presence of monensin yielded lower proportions of IL-10+ T cells (0.45% (0.28–0.80) versus 0.80% (0.50–1.50) of CD4+ T cells, p < 0.01), although monensin addition did result in an increased MFI (2431 (1273–4959) versus 1928 (1147–3760), p < 0.01). Detectable fractions of IL-17A+ CD4+ T cells were not affected by monensin. A shorter incubation time, but not lower monensin concentrations, was effective in improving the detection of IL-10+ T cells. We found a strong correlation between the fraction of IL-10+ CD4+ T cells in the presence and absence of monensin (R = 0.80 p < 0.01). Next to this, also the detection of IL-10+ NK-T cells and IL-10+ monocytes, but not IL-10+ B cells, is impaired in the presence of monensin.

This study shows that the effect of monensin on cytokine accumulation is time and cytokine dependent. Due to the use of monensin, previous research may have underestimated the number of IL-10+ leukocytes or may even have not been able to detect them at all. It is important to consider this for future research or when interpreting historical IL-10 data.

CANCER IMMUNO POSTER

by Tanmoy Bhaduri

Why are dendritic cells central to cancer immunotherapy?

by Camilo Colaco

BioHealthBase: informatics support in the elucidation of influenza virus host pathogen interactions and virulence.

by R. Burke Squires

Genetic deletion of dectin-1 does not affect the course of murine experimental colitis

by Shobhit Dhawan

BMC Gastroenterology

It is believed that inflammatory bowel diseases (IBD) result from an imbalance in the  intestinal immune response... more It is believed that inflammatory bowel diseases (IBD) result from an imbalance in the  intestinal immune response towards the luminal microbiome. Dectin-1 is a widely expressed  pattern recognition receptor that recognizes fungi and upon recognition it mediates cytokine  responses and skewing of the adaptive immune system. Hence, dectin-1 may be involved in  the pathogenesis of IBD.

EFECTO DE LOS EXTRACTOS DE ORGANOS HEMATOPOYETICOS DEL TIBURON NODRIZA, Ginglymostoma cirratum (BONNATERRE, 1788) EN UN CULTIVO in vitro DE CELULAS TUMORALES

by Leonardo Mantilla Aldana

Memorias X Seminario Nacional de Ciencias y Tecnologías del Mar. Octubre 28 – 31, 1996.

A preliminary study of the effects of the aquoses extracts of the nurse shark (Ginglymostoma cirratum) haematopoietic... more A preliminary study of the effects of the aquoses extracts of the nurse shark (Ginglymostoma cirratum) haematopoietic organs (liver, epigonadal organ, kidney, cartilage and plasma), on the culture of the tumorals cells producer of specific antibodies with the A blood group (hibridomas) was carried out. The experiments were complemented with a control of specifity using the liver and cartilage extracts of the skate Rhinobatos percellens. The monitoring of the growth and metabolism showed that the
epigonal organ extract caused apoptosis in the hibridomas, the liver extract and the plasma provoked cell necrosis and the other extracts as the liver and cartilage of the skate caused inhibition on the growth and cell metabolism.

Effect of ocean acidification on the immune response of the blue mussel, Mytilus edulis

by Ruth N. Bibby

Monitoring of Regulatory T Cell Frequencies and Expression of CTLA-4 on T Cells, before and after DC Vaccination, Can Predict Survival in GBM Patients

by Richard Jin

Brendan Fong, Richard Jin, Xiaoyan Wang, Michael Safaee, Dominique N. Lisiero, Isaac Yang, Gang Li, Linda M. Liau, Robert M. Prins

Purpose

Dendritic cell (DC) vaccines have recently emerged as an innovative therapeutic option for... more Purpose

Dendritic cell (DC) vaccines have recently emerged as an innovative therapeutic option for glioblastoma patients. To identify novel surrogates of anti-tumor immune responsiveness, we studied the dynamic expression of activation and inhibitory markers on peripheral blood lymphocyte (PBL) subsets in glioblastoma patients treated with DC vaccination at UCLA.

Experimental Design

Pre-treatment and post-treatment PBL from 24 patients enrolled in two Phase I clinical trials of dendritic cell immunotherapy were stained and analyzed using flow cytometry. A univariate Cox proportional hazards model was utilized to investigate the association between continuous immune monitoring variables and survival. Finally, the immune monitoring variables were dichotomized and a recursive partitioning survival tree was built to obtain cut-off values predictive of survival.

Results

The change in regulatory T cell (CD3+CD4+CD25+CD127low) frequency in PBL was significantly associated with survival (p = 0.0228; hazard ratio = 3.623) after DC vaccination. Furthermore, the dynamic expression of the negative co-stimulatory molecule, CTLA-4, was also significantly associated with survival on CD3+CD4+ T cells (p = 0.0191; hazard ratio = 2.840) and CD3+CD8+ T cells (p = 0.0273; hazard ratio = 2.690), while that of activation markers (CD25, CD69) was not. Finally, a recursive partitioning tree algorithm was utilized to dichotomize the post/pre fold change immune monitoring variables. The resultant cut-off values from these immune monitoring variables could effectively segregate these patients into groups with significantly different overall survival curves.

Conclusions

Our results suggest that monitoring the change in regulatory T cell frequencies and dynamic expression of the negative co-stimulatory molecules on peripheral blood T cells, before and after DC vaccination, may predict survival. The cut-off point generated from these data can be utilized in future prospective immunotherapy trials to further evaluate its predictive validity.

Evaluating the immunological response to hepatitis B vaccination in HIV-infected patients in clinical practice

by Guillermo Mena Pinilla

Immunogenicity and efficacy of codon optimized DNA vaccines encoding the F-protein of respiratory syncytial virus

by Nicola Ternette

The Ability of Murine Dendritic Cell Subsets to Direct T Helper Cell Differentiation is Dependent on Microbial Signals

by Alexander Edwards

Harrison, R.A., W. Wüster & R.D.G. Theakston (2003) The conserved structure of snake venom toxins confers extensive immunological cross-reactivity to toxin-specific antibody. Toxicon 41: 441-449.

by Wolfgang Wüster

Tick saliva induces regulatory dendritic cells: MAP-kinases and Toll-like receptor-2 expression as potential targets

by Fredy RS Gutierrez

Oliveira CJ, Carvalho WA, Garcia GR, Gutierrez FR, de Miranda Santos IK, Silva JS, Ferreira BR.
Department of Biochemistry and Immunology, School of Medicine of Ribeirão Preto, University of São Paulo, SP, Brazil.

Ticks (Acari: Ixodidae) are bloodsucking ectoparasitic arthropods of human and veterinary medical importance. Tick... more Ticks (Acari: Ixodidae) are bloodsucking ectoparasitic arthropods of human and veterinary medical importance. Tick saliva has been shown to contain a wide range of bioactive molecules with vasodilatory, antihemostatic, and immunomodulatory activities. We have previously demonstrated that saliva from Rhipicephalus sanguineus ticks inhibits the maturation of dendritic cells (DCs) stimulated with LPS. Here we examined the mechanism of this immune subversion, evaluating the effect of tick saliva on Toll-like receptor (TLR)-4 signalling pathway in bone marrow-derived DCs. We demonstrated that R. sanguineus tick saliva impairs maturation of DCs stimulated with LPS, a TLR-4 ligand, leading to increased production of interleukin (IL)-10 and reduced synthesis of IL-12p70 and TNF-alpha. The immunomodulatory effect of the tick saliva on the production of pro-inflammatory cytokines by DCs stimulated with LPS was associated with the observation that tick saliva inhibits the activation of the ERK 1/2 and p38 MAP kinases. These effects were independent of the expression of TLR-4 on the surface of DCs. Additionally, saliva-treated DCs also presented a similar pattern of cytokine modulation in response to other TLR ligands. Since the recent literature reports that several parasites evade immune responses through TLR-2-mediated production of IL-10, we evaluated the effect of tick saliva on the percentage of TLR-2(+) DCs stimulated with the TLR-2 ligand lipoteicoic acid (LTA). The data showed that the population of DCs expressing TLR-2 was significantly increased in DCs treated with LTA plus saliva. In addition, tick saliva alone increased the expression of TLR-2 in a dose- and time-dependent manner. Our data suggest that tick saliva induces regulatory DCs, which secrete IL-10 and low levels of IL-12 and TNF-alpha when stimulated by TLR ligands. Such regulatory DCs are associated with expression of TLR-2 and inhibition of ERK and p38, which promotes the production of IL-10 and thus down-modulates the host's immune response, possibly favouring susceptibility to tick infestations.

Efficient CRM197-mediated drug targeting to monocytes

by Nicolas Legrand

G.J. Schenk et al.; Journal of Controlled Release (2012)

Efficient delivery of drugs to specific cellular reservoirs is of particular importance for therapeutics that are not... more Efficient delivery of drugs to specific cellular reservoirs is of particular importance for therapeutics that are not able to pass cellular barriers and that may have unwanted side effects in off-target tissues. Heparin-binding epidermal growth factor (HB-EGF) is expressed on leukocytes and may be targeted for specific drug delivery using cross-reacting material (CRM)197, a non-toxic variant of diphtheria toxin and exogenous substrate for HB-EGF. We used fluorescently labeled CRM197 and CRM197-coated liposomes to investigate their potential use for drug delivery to leukocytes. We demonstrate that CRM197-guided systems are efficiently taken up by human leukocytes in vitro. CRM197 was also found to specifically target leukocytes in vivo in mice with components of the human immune system (HIS mice) and hamsters. Monocytes represent the most prominent subset of leukocytes that showed highly specific CRM197-mediated uptake. We therefore propose the application of CRM197 as a novel targeting approach in diseases that require the selective treatment of monocytes.

Stem cell factor consistently improves thymopoiesis after experimental transplantation of murine or human hematopoietic cells in immunodeficient mice

by Nicolas Legrand

E.J. Wils et al.; The Journal of Immunology (2011)

Deficient thymopoiesis is a pivotal determinant of impaired immune competence following hematopoietic stem cell... more Deficient thymopoiesis is a pivotal determinant of impaired immune competence following hematopoietic stem cell transplantation (HSCT). Stem cell factor (SCF) is essentially involved in early thymopoiesis. We evaluated whether SCF administration would improve recovery of thymopoiesis following HSCT in immunodeficient mice receiving: 1) bone marrow (BM) transplantation of congenic mice; or 2) human fetal liver HSCT in the human immune system mouse model. Following murine BM transplantation, SCF significantly enhanced thymopoiesis and peripheral T cell recovery in lymph nodes and spleen. SCF did not affect BM lymphoid progenitor recovery and/or expansion. Median thymic cellularity increased from 0.9 in PBS- to 266 × 10(4)/thymus in SCF-treated mice (p = 0.05). Following human HSCT in human immune system mice, higher thymic cellularity was observed in SCF-treated mice. Double-negative and early double-positive thymocyte subsets increased, but especially late double-positive, CD4 single-positive, and CD8 single-positive thymocyte subsets were significantly enhanced (p < 0.05). These results show that exogenous supply of SCF may significantly improve murine and human posttransplant thymopoiesis, for which the effect is probably exerted by directly promoting T cell development intrathymically rather than by enhanced entry of prethymically expanded lymphoid progenitors.

Autonomous and extrinsic regulation of thymopoiesis in human immune system (HIS) mice

by Nicolas Legrand

N.D. Huntington et al.; European Journal of Immunology (2011)

Human Immune System (HIS) mice represent a novel biotechnology platform to dissect human haematopoiesis and immune... more Human Immune System (HIS) mice represent a novel biotechnology platform to dissect human haematopoiesis and immune responses. However, the limited human T-cell development that is observed in HIS mice restricts its utility for these applications. Here, we address whether reduced thymopoiesis in HIS mice reflects an autonomous defect in T-cell precursors and/or a defect in the murine thymic niche. Human thymocyte precursors seed the mouse thymus and their reciprocal interactions with murine thymic epithelial cells (TECs) led to both T-cell and TEC maturation. The human thymocyte subsets observed in HIS mice demonstrated survival, proliferative and phenotypic characteristics of their normal human counterparts, suggesting that the intrinsic developmental program of human thymocytes unfolds normally in this xenograft setting. We observed that exogenous administration of human IL-15/IL-15Rα agonistic complexes induced the survival, proliferation and absolute numbers of immature human thymocyte subsets, without any obvious effect on cell-surface phenotype or TCR Vβ usage amongst the newly selected mature single-positive (SP) thymocytes. Finally, when IL-15 was administered early after stem cell transplantation, we noted accelerated thymopoiesis resulting in the more rapid appearance of peripheral naïve T cells. Our results highlight the functional capacity of murine thymic stroma cells in promoting human thymopoiesis in HIS mice but suggest that the "cross-talk" between murine thymic stroma and human haematopoietic precursors may be suboptimal. As IL-15 immunotherapy promotes early thymopoiesis, this novel approach could be used to reduce the period of T-cell immunodeficiency in the post-transplant clinical setting.

AF1q/MLLT11 regulates the emergence of human prothymocytes through cooperative interaction with the Notch signaling pathway

by Nicolas Legrand

A. Parcelier et al.; Blood (2011)

The mechanisms regulating the emergence of BM prothymocytes remain poorly characterized. Genome-wide transcriptome... more The mechanisms regulating the emergence of BM prothymocytes remain poorly characterized. Genome-wide transcriptome analyses looking for genes expressed in human prothymocytes led to the identification of AF1q/MLLT11 as a candidate gene conceivably involved in this process. Analysis of AF1q protein subcellular localization and intracellular trafficking showed that despite pronounced karyophily, it was subjected to constitutive nuclear export followed by ubiquitin-mediated degradation in the centrosomal area. Using in vitro assays based on either forced expression or shRNA-mediated silencing of AF1q, we provide evidence that the protein promotes T- over B-cell differentiation in multipotent hematopoietic progenitors. At the molecular level, AF1q confers to multipotent progenitors an increased susceptibility to Delta-like/Notch-mediated signaling. Consistent with these findings, enforced AF1q expression in humanized mice fosters the emergence of BM CD34(+)CD7(+) prothymocytes, enhances subsequent thymus colonization, and accelerates intrathymic T-cell development. In contrast, AF1q silencing provokes a global shift of BM lymphopoiesis toward the B-cell lineage, hinders prothymocyte development, inhibits thymus colonization, and leads to intrathymic accumulation of B cells. Our results indicate that AF1q cooperates with the Notch signaling pathway to foster the emergence of BM prothymocytes and drive subsequent intrathymic specification toward the T-cell lineage.