Use of an anti-CD200 antibody for prolonging the survival of allografts: a patent evaluation of WO2012106634A1

Pre-transplant CD200 and CD200R1 concentrations are associated with post-transplant events in kidney transplant recipients

CD200 is an immunoglobulin superfamily membrane protein that binds to a myeloid cell-specific receptor and induces inhibitory signaling. The aim of this study was to investigate the role of CD200 and its receptor (CD200R1) on kidney transplant (KTx) outcome. In a collective of 125 kidney recipients (University hospital, Heidelberg, Germany), CD200 and CD200R1 concentrations were evaluated immediately before transplantation. Recipient baseline and clinical characteristics and KTx outcome, including acute rejection (AR), acute tubular necrosis, delayed graft function, cytomegalovirus (CMV) and human polyomaviridae (BK) virus infections, and graft loss were evaluated during the first post-transplant year. The association of CD200 and CD200R1 concentrations and CD200R1/CD200 ratios with the outcome of KTx was investigated for the first time in a clinical setting in a prospective cohort. There was a positive association between pre-transplant CD200R1 concentrations and CMV (re)activation (P = .041). Also, increased CD200R1 concentration was associated with a longer duration of CMV infection (P = .049). Both the frequency of AR and levels of creatinine (3 and 6 months after KTx) were significantly higher in patients with an increased CD200R1/CD200 ratio (median: 126 vs 78, P = .008). Increased pre-transplant CD200R1/CD200 ratios predict immunocompetence and risk of AR, whereas high CD200R1 concentrations predict immunosuppression and high risk of severe CMV (re)activation after KTx.

Effects of Infliximab against Methotrexate Toxicity in Splenic Tissue via the Regulation of CD3, CD68, and C200R in Rats

Methotrexate (MTX), which has been used in clinical practice for approximately 70 years, is still widely employed in the treatment of rheumatoid arthritis (RA), psoriasis, and cancer. Although MTX toxicity causes nephrotoxicity, hepatotoxicity, bone marrow suppression, pulmonary fibrosis, and gastrointestinal damage, previous studies have not addressed splenic toxicity. This is the first study to examine the effectiveness of infliximab (INF) against MTX-induced toxicity in splenic tissues via the regulation of CD3, CD68, and C200R. We investigated the effects of MTX on macrophages and T lymphocytes in the spleen at the molecular level and examined the protective potential of the tumor necrosis factor (TNF)-α antagonist INF against MTX toxicity. Three groups of rats were set up. Group 1 received saline solution only, group 2 a single dose of MTX (20 mg/kg), and group 3 INF (7 mg/kg) before administration of a single dose of MTX (20 mg/kg). All injections were given intraperitoneally. Spleen tissues were removed 5 days after MTX administration and evaluated for CD3, CD68, and CD200R using immunohistochemical staining. Finally, the mean numerical density of CD3+, CD68+, and CD200R+ cells was estimated by a histopathologist using StereoInvestigator 8. MTX increased the numerical densities of CD3+, CD68+, and CD200R+ cells (p < 0.05). We also observed that INF reduced the numerical densities of these cells following MTX administration (p < 0.05). INF may, therefore, be a promising candidate for the prevention of the deleterious effects on spleen tissue of MTX, used in the treatment of RA and cancer.

High serum soluble CD200 levels in patients with autosomal dominant polycystic kidney disease

CD200 is a novel immune-effective molecule, existing in a cell membrane-bound form, as well as in a soluble form in serum, which performs to modulate inflammatory and acquired immune responses. Autosomal dominant polycystic kidney disease (ADPKD) is characterized by the development of large renal cysts and progressive loss of renal function. As defects in cell cycle arrest and apoptosis of renal tubular epithelial cells occur in ADPKD, we asked whether serum soluble CD200 might underlie and effect on ADPKD. Serum soluble CD200 levels were measured in 44 patients with ADPKD and 24 healthy volunteers. Concentrations of soluble CD200 in the serum samples were quantified using an ELISA kit. The mean serum soluble CD200 levels were higher in patients with ADPKD than in the control group (71.4±29.2 and 21.4±5.6 pg/mL, p<0.001). Positive correlation was detected between serum soluble CD200 levels and glomerular filtration rate (r=0.772, p<0.001), and serum albumin level (r=0.466, p=0.001). Negative correlation was detected between serum soluble CD200 levels and serum creatinine levels (r=-0.761, p<0.001), and C reactive protein levels (r=-0.364, p=0.015). In the ADPKD patients group, serum soluble CD200 levels were lower in patients with stage 5 chronic kidney disease (CKD) than in patients with stages 1-2 (p<0.001), 3 (p=0.005) and 4 CKD (p=0.006). Serum soluble CD200 levels were similar in patients with stages 1-2, 3, and 4 CKD (p>0.05). Our results show that patients with ADPKD have activated soluble CD200 levels which were related to renal function and inflammation.

Lung CD200 Receptor Activation Abrogates Airway Hyperresponsiveness in Experimental Asthma

In allergic asthma, homeostatic pathways are dysregulated, which leads to an immune response toward normally innocuous antigens. The CD200-CD200 receptor pathway is a central regulator of inflammation, and CD200 expression was recently found to be down-regulated in circulating leukocytes of patients with asthma. Given the antiinflammatory properties of CD200, we investigated whether local delivery of recombinant CD200 (rCD200) could reinstate lung homeostasis in an experimental model of asthma. Brown Norway rats were sensitized with ovalbumin (OVA) and alum. rCD200 was intratracheally administered 24 hours before OVA challenge, and airway responsiveness to methacholine was measured 24 hours after the allergen challenge. Inflammation was also assessed by measuring cell recruitment and cytokine levels in bronchoalveolar lavages, as well as lung and draining lymph node accumulation of dendritic cells (DCs) and T cells. In sensitized rats, rCD200 abolished airway hyperresponsiveness, whereas the sham treatment had no effect. In addition, rCD200 strongly reduced OVA-induced lung accumulation of myeloid DCs, CD4(+) T cells, and T helper type 2 cells. This was associated with a strong reduction of OVA-induced IL-13 level and with an increase of IL-10 in supernatants of bronchoalveolar lavages. Lung eosinophilia and draining lymph node accumulation of myeloid DCs and T cells were not affected by rCD200. Overall, these data reveal that rCD200 can inhibit airway hyperresponsiveness in a model of asthma by a multistep mechanism associated with local alterations of the T cell response and the cytokine milieu.

Addressing the Inflammatory Response to Clinically Relevant Polymers by Manipulating the Host Response Using ITIM Domain-Containing Receptors

Tissue contacting surfaces of medical devices initiate a host inflammatory response, characterized by adsorption of blood proteins and inflammatory cells triggering the release of cytokines, reactive oxygen species (ROS) and reactive nitrogen species (RNS), in an attempt to clear or isolate the foreign object from the body. This normal host response contributes to device-associated pathophysiology and addressing device biocompatibility remains an unmet need. Although widespread attempts have been made to render the device surfaces unreactive, the establishment of a completely bioinert coating has been untenable and demonstrates the need to develop strategies based upon the molecular mechanisms that define the interaction between host cells and synthetic surfaces. In this review, we discuss a family of transmembrane receptors, known as immunoreceptor tyrosine-based inhibitory motif (ITIM)-containing receptors, which show promise as potential targets to address aberrant biocompatibility. These receptors repress the immune response and ensure that the intensity of an immune response is appropriate for the stimuli. Particular emphasis will be placed on the known ITIM-containing receptor, Signal Regulatory Protein Alpha (SIRPhα), and its cognate ligand CD47. In addition, this review will discuss the potential of other ITIM-containing proteins as targets for addressing the aberrant biocompatibility of polymeric biomaterials.

Placental mesenchymal stem cells of fetal and maternal origins demonstrate different therapeutic potentials

Introduction

Therapeutic potentials of mesenchymal stem cells (MSCs) from different sources have been evaluated in pre-clinical and clinical settings. Although MSCs from different sources share MSC-specific characteristics and functions, inconsistent or controversial results of pre-clinical and clinical applications of such cells are frequently reported. This may be partially due to the fact that MSCs isolated from different origins may differentially express some functions not typical for MSCs, and hence have different therapeutic potentials. The aim of this study is to investigate the differences in human placental MSCs (P-MSCs) of fetal and maternal origins in the aspects of clinical importance.

Methods

P-MSCs of fetal and maternal origins isolated from normal term placentas were characterized for their typical phenotype as well as their expression of receptors and growth factors of clinic interests. P-MSCs that preferentially express hepatocyte growth factor (HGF) and CD200 were evaluated for their therapeutic potentials in models of angiogenesis and allogeneic skin transplantation, in comparison with their HGF and CD200 negative partners.

Results

Although all P-MSCs express typical MSC phenotype, fetal but not maternal P-MSCs express high levels of CD200 and HGF. Compared with HGF and CD200 negative P-MSCs, HGF and CD200 positive cells demonstrated significantly high potentials in promoting angiogenesis in vitro and increasing immunosuppressive function in vivo. These therapeutic potentials were at least in part due to their differences in HGF and CD200 expression, respectively.

Conclusions

We conclude that MSC origins may have significant impact on the therapeutic potentials of such cells, and should be taken into consideration in clinical applications.