Anti-PDCD1 Monoclonal antibody, clone K206 [APC]

Objective: To elucidate the genetic predisposition of Rasmussen syndrome (RS). Methods: In 29 Japanese patients, we examined the genome sequences of cytotoxic T-lymphocyte-associated protein 4 (CTLA4), programmed cell-death 1 (PDCD1), and T-bet (TBX21) genes by direct sequencing, and evaluated the significance of SNPs (single nucleotide polymorphism) by comparison with Hap Map data. Results: In all patients, no disease-causative mutations were found in CTLA4, PDCD1, and T-bet. However, rs231775 SNP in exon 1 of CTLA4 showed significant positive genotypic (p = 0.0363) and allelic associations (p = 0.0137) with onset of RS compared with Japanese controls, as did rs231779 SNP in intron 1 of CTLA4 (p = 0.0467 and 0.0188, respectively). Also, rs2227982 SNP in exon 5 of PDCD1 showed significant positive genotypic and allelic associations with RS (p = 0.0145 and 0.0114, respectively). Poor cognitive outcome (IQ below 50) was found in 0% of wild type (C/C), 9% of heterologous (C/T) and 25% of homologous (T/T) genotype of rs2227982. Quadriplegia was found only in homologous (T/T) genotype, and hemiplegia was in heterologous (C/T) and homologous (T/T) genotype of rs2227982. No association between SNPs of T-bet and RS onset was found. Regarding SNPs in promoter regions (rs4794067 and rs17250932) of T-bet, however, IQ below 50 was found in 19% of wild type (TIT) and 0% of heterologous (TIC) genotype of rs4794067, and in 19% of wild type (TIT) and 0% of heterologous (TIC) genotype of rs17250932. Quadriplegic patients were found only in wild-type patients (rs4794067 and rs17250932). Conclusions: We identified three SNPs (rs231775, rs231779, rs2227982) as some of the SNPs associated with onset of Japanese RS. We need further studies in other populations to confirm these genetic predispositions in RS. (C) 2013 Elsevier B.V. All rights reserved.

Previously, we documented the role of the programmed death-1 (PD-1, also known as PDCD1) pathway in macrophage apoptosis and the downregulation of this signaling during infection by the intra-macrophage parasite Leishmania donovani. However, we also found that, during the late phase of infection, PD-1 expression was significantly increased without activating host cell apoptosis; here we show that inhibition of PD-1 led to markedly decreased parasite survival, along with increased production of TNF alpha, IL-12, reactive oxygen species (ROS) and nitric oxide (NO). Increased PD-1 led to inactivation of AKT proteins resulting in nuclear sequestration of FOXO-1. Transfecting infected cells with constitutively active FOXO-1 (CA-FOXO) led to increased cell death, thereby suggesting that nuclear FOXO-1 might be inactivated. Infection significantly induced the expression of SIRT1, which inactivated FOXO-1 through deacetylation, and its knockdown led to increased apoptosis. SIRT1 knockdown also significantly decreased parasite survival along with increased production of TNF alpha, ROS and NO. Administration of the SIRT1 inhibitor sirtinol (10 mg/kg body weight) in infected mice decreased spleen parasite burden and a synergistic effect was found with PD-1 inhibitor. Collectively, our study shows that Leishmania utilizes the SIRT1/FOXO-1 axis for differentially regulating PD-1 signaling and, although they are interconnected, both pathways independently contribute to intracellular parasite survival. This article has an associated First Person interview with the first author of the paper.