Foxp3+ T cells induce Perforin-Dependent Dendritic Cell Death in Tumor-Draining Lymph Nodes.

Regulatory T (Treg) cells limit the onset of effective antitumor immunity, through yet-ill-defined mechanisms. We showed the rejection of established ovalbumin (OVA)-expressing MCA101 tumors required both the adoptive transfer of OVA-specific CD8(+) T cell receptor transgenic T cells (OTI) and the neutralization of Foxp3(+) T cells. In tumor-draining lymph nodes, Foxp3(+) T cell neutralization induced a marked arrest in the migration of OTI T cells, increased numbers of dendritic cells (DCs), and enhanced OTI T cell priming. Using an in vitro cytotoxic assay and two-photon live microscopy after adoptive transfer of DCs, we demonstrated that Foxp3(+) T cells induced the death of DCs in tumor-draining lymph nodes, but not in the absence of tumor. DC death correlated with Foxp3(+) T cell-DC contacts, and it was tumor-antigen and perforin dependent. We conclude that Foxp3(+) T cell-dependent DC death in tumor-draining lymph nodes limits the onset of CD8(+) T cell responses.

CD207+ CD103+ dermal dendritic cells cross-present keratinocyte-derived antigens irrespective of the presence of Langerhans cells.

Recent studies have challenged the view that Langerhans cells (LCs) constitute the exclusive antigen-presenting cells of the skin and suggest that the dermal dendritic cell (DDC) network is exceedingly complex. Using knockin mice to track and ablate DCs expressing langerin (CD207), we discovered that the dermis contains five distinct DC subsets and identified their migratory counterparts in draining lymph nodes. Based on this refined classification, we demonstrated that the quantitatively minor CD207+ CD103+ DDC subset is endowed with the unique capability of cross-presenting antigens expressed by keratinocytes irrespective of the presence of LCs. We further showed that Y-Ae, an antibody that is widely used to monitor the formation of complexes involving I-Ab molecules and a peptide derived from the I-E alpha chain, recognizes mature skin DCs that express I-Ab molecules in the absence of I-E alpha. Knowledge of this extra reactivity is important because it could be, and already has been, mistakenly interpreted to support the view that antigen transfer can occur between LCs and DDCs. Collectively, these data revisit the transfer of antigen that occurs between keratinocytes and the five distinguishable skin DC subsets and stress the high degree of functional specialization that exists among them.

Loss of the LAT adaptor converts antigen-responsive T cells into pathogenic effectors that function independently of the T cell receptor.

Despite compromised T cell antigen receptor (TCR) signaling, mice in which tyrosine 136 of the adaptor linker for activation of T cells (LAT) was constitutively mutated (Lat(Y136F) mice) accumulate CD4(+) T cells that trigger autoimmunity and inflammation. Here we show that equipping postthymic CD4(+) T cells with LATY136F molecules or rendering them deficient in LAT molecules triggers a lymphoproliferative disorder dependent on prior TCR engagement. Therefore, such disorders required neither faulty thymic T cell maturation nor LATY136F molecules. Unexpectedly, in CD4(+) T cells recently deprived of LAT, the proximal triggering module of the TCR induced a spectrum of protein tyrosine phosphorylation that largely overlapped the one observed in the presence of LAT. The fact that such LAT-independent signals result in lymphoproliferative disorders with excessive cytokine production demonstrates that LAT constitutes a key negative regulator of the triggering module and of the LAT-independent branches of the TCR signaling cassette.

Molecular diversity of the HLA-C gene identified in a Caucasian population

A DNA typing procedure, based on a two stage polymerase chain reaction-sequence-specific oligonucleotide probe (PCR-SSOP) typing strategy, has been developed and applied to DNA from 1000 healthy individuals from the Northern Ireland region. The two-stage procedure involves human leukocyte antigen (HLA-C) identification through the use of a medium resolution PCR-SSOP system, followed by four secondary group specific PCR-SSOP systems, to enable allele resolution. The PCR-SSOP systems were designed for the identification of HLA-Cw alleles with possible discrimination within exons 2 and 3 of the HLA-C gene, i.e., HLA-Cw*01-Cw*16. PCR-SSP tests were designed for the resolution of HLA-Cw*17 and -Cw*18 alleles. The systems can also be used independently of each other if selective allele resolution is required. HLA-Cw allele frequencies occuring within the Northern Ireland population have been compiled, along with estimations of HLA-B/Cw haplotype frequencies. (C) American Society for Histocompatibility and Immunogenetics, 2002. Published by Elsevier Science Inc.

Respiratory syncytial virus (RSV) vaccines - Two steps back for one leap forward

Respiratory viruses are among the most important causes of morbidity and mortality worldwide. From a vaccine viewpoint, such viruses may be divided into two principle groups-those where infection results in long-term immunity and whose continued survival requires constant mutation, and those where infection induces incomplete immunity and repeated infections are common, even with little or no mutation. Influenza virus and respiratory syncytial virus (RSV) typify the former and latter groups, respectively. Importantly, successful vaccines have been developed against influenza virus. However, this is not the case for RSV, despite many decades of research and several vaccine approaches. Similar to natural infection, the principle limitation of candidate RSV vaccines in humans is limited immunogenicity, characterised in part by short-term RSV-specific adaptive immunity. The specific reasons why natural RSV infection is insufficiently immunogenic in humans are unknown but circumvention of innate and adaptive immune responses are likely causes. Fundamental questions concerning RSV/host interactions remain to be addressed at both the innate and adaptive immune levels in humans in order to elucidate mechanisms of immune response circumvention. Taking the necessary steps back to generate such knowledge will provide the means to leap forward in our quest for a successful RSV vaccine. Recent developments relating to some of these questions are discussed. (C) 2007 Elsevier B.V. All rights reserved.

Does airways inflammation pre-exist before late onset wheeze in children?

Epidemiological studies show that some children develop wheezing after 3 yr of age which tends to persist. It is unknown how this starts or whether there is a period of asymptomatic inflammation. The aim of this study is to determine whether lower airway allergic inflammation pre-exists in late onset childhood wheeze (LOCW). Follow-up study of children below 5 yr who had a non-bronchoscopic bronchoalveolar lavage (BAL) performed during elective surgery. The children had acted as normal controls. A modified ISAAC questionnaire was sent out at least 7 yr following the initial BAL, and this was used to ascertain whether any children had subsequently developed wheezing or other atopic disease (eczema, allergic rhinitis). Cellular and cytokine data from the original BAL were compared between those who never wheezed (NW) and those who had developed LOCW. Eighty-one normal non-asthmatic children were recruited with a median age of 3.2 . Of the 65 children contactable, 9 (16.7%) had developed wheeze, 11 (18.5%) developed eczema and 14 (22.2%) developed hay fever. In five patients, wheeze symptoms developed mean 3.3- yr (range: 2–5 yr) post-BAL. Serum IgE and blood eosinophils were not different in the LOCW and NW, although the blood white cell count was lower in the LOCW group. The median BAL eosinophil % was significantly increased in the patients with LOCW (1.55%, IQR: 0.33 to 3.92) compared to the children who never wheezed, NW (0.1, IQR: 0.0 to 0.3, p = 0.01). No differences were detected for other cell types. There are no significant differences in BAL cytokine concentrations between children with LOCW and NW children. Before late onset childhood wheezing developed, we found evidence of elevated eosinophils in the airways. These data suggest pre-existent airways inflammation in childhood asthma some years before clinical presentation.

Monoclonal antibody development for acrylamide-adducted human haemoglobin; A biomarker of dietary acrylamide exposure

The spontaneous formation of the neurotoxic carcinogen acrylamide in a wide range of cooked foods has recently been discovered, leading to dietary exposure estimates of 30.8 mu g of acrylamide day(-1) for an average 77 kg human male. This is considerably higher than the European legal limit of acrylamide in drinking water, which is approximately 0.2 mu g of acrylamide person(-1) day(-1). A recent study of 62,573 women over 11.3 years has observed an increased risk of postmenopausal endometrial and ovarian cancer (but not breast cancer) with increasing dietary acrylamide intake, demonstrating significant risk to human health. As individual acrylamide exposure is affected by dietary habits, cooking methods, and cigarette consumption; accurate extrapolation from estimated dietary exposure is extremely difficult. Quantifying biomarkers of acrylamide exposure therefore remains the most effective means of rapidly determining individual exposure to acrylamide, and correlating exposure with lifestyle choices. Current methodologies for the analysis of blood biomarkers of acrylamide are focused on expensive, slower chromatographic techniques such as GC and LC coupled to mass spectrometry. This paper describes the first successful development of two monoclonal antibodies specific to acrylamide-adducted haemoglobin (IC50 of 94 ng ml(-1) and 198 ng ml(-1)), that are suitable for use in a high-throughput biomarker immunoassay to determine individual acrylamide exposure. Further development of acrylamide-haemoglobin standards with defined levels of acrylamide adduction will enable a fully quantitative assay, and allow sensitivity comparisons with alternative chromatographic methods of analysis. (C) 2008 Elsevier B.V. All rights reserved.

Enhanced lymphocyte interferon (IFN)-γ responses in a PTEN mutation-negative Cowden disease kindred.

Identification of immune modifiers of inherited cancer syndromes may provide a rationale for preventive therapy. Cowden disease (CD) is a genetically heterogeneous inherited cancer syndrome that arises predominantly from germline phosphatase and tensin homologue deleted on chromosome 10 (PTEN) mutation and increased phosphoinositide 3-kinase/mammalian target of rapamycin (PI3K/mTOR) signalling. However, many patients with classic CD diagnostic features are mutation-negative for PTEN (PTEN M-Neg). Interferon (IFN)-gamma can modulate the PI3K/mTOR pathway, but its association with PTEN M-Neg CD remains unclear. This study assessed IFN-gamma secretion by multi-colour flow cytometry in a CD kindred that was mutation-negative for PTEN and other known susceptibility genes. Because IFN-gamma responses may be regulated by killer cell immunoglobulin-like receptors (KIR) and respective human leucocyte antigen (HLA) ligands, KIR/HLA genotypes were also assessed. Activating treatments induced greater IFN-gamma secretion in PTEN M-Neg CD peripheral blood lymphocytes versus healthy controls. Increased frequency of activating KIR genes, potentially activating KIR/HLA compound genotypes and reduced frequency of inhibitory genotypes, were found in the PTEN M-Neg CD kindred. Differences of IFN-gamma secretion were observed among PTEN M-Neg CD patients with distinct KIR/HLA compound genotypes. Taken together, these findings show enhanced lymphocyte secretion of IFN-gamma that may influence the PI3K/mTOR CD causal molecular pathway in a PTEN mutation-negative CD kindred.

Antibody-targeted nanoparticles for cancer therapy

In recent years, nanoparticulate-mediated drug delivery research has examined a full spectrum of nanoparticles that can be used in diagnostic and therapeutic cancer applications. A key aspect of this technology is in the potential to specifically target the nanoparticles to diseased cells using a range of molecules, in particular antibodies. Antibody-nanoparticle conjugates have the potential to elicit effective targeting and release of therapeutic targets at the disease site, while minimizing off-target side effects caused by dosing of normal tissues. This article provides an overview of various antibody-conjugated nanoparticle strategies, focusing on the rationale of cell-surface receptors targeted and their potential clinical application.

Ankle disease in juvenile idiopathic arthritis: ultrasound findings in clinically swollen ankles

The ankle joint is frequently involved in juvenile idiopathic arthritis (JIA), but it is unclear whether this is predominantly due to synovitis, tenosynovitis, or both. We performed clinic-based ultrasound examination to assess the prevalence of synovitis and tenosynovitis in children with JIA felt clinically to have active inflammatory disease of the ankle.