A Role of T Cell Receptor Specificity in the Thymic Regulatory T Cell Development

The development of regulatory T: Treg) cells is essential for the maintenance of immune tolerance and homeostasis. In the thymus, TCR-specificity to self-antigen appears to be a primary determinant for Treg cell lineage commitment, imprinting both self and foreign antigens in the peripheral Treg cell population to provide dominant tolerance. The degree of T cell self-reactivity considered dangerous by the immune system, thereby requiring thymic education to prevent autoimmunity, is unknown. Here, I analyzed a panel of TCRs with a broad range of reactivity to ovalbumin: OVA323-339) in the RIP-mOVA self-antigen model for their ability to induce mechanisms of thymic tolerance. Thymic Treg cell generation in vivo was directly correlated with reactivity to OVA-peptide in a broad ~1,000-fold range, and its developmental niche size was unexpectedly dependent on TCR affinity. The threshold for Treg cell differentiation was almost 100-fold lower than that required for eliciting thymic negative selection and peripheral T cell responses. Thus, these data suggest that Treg cell differentiation is a default outcome of self-antigen encounter for CD4+ thymocytes, and that thymic tolerance mechanisms are tuned to limit the escape of self-reactive effectors without Treg cell chaperones into the periphery. In addition, in the study of developmental stage of Treg cells, I demonstrated that differentiation of most Treg cells occurs at immature CD4SP subset, suggesting that medullary APCs may facilitate maturation of thymocyte after positive selection for efficient induction of Foxp3. In summary, this study suggest that Treg cell development is driven by self-antigen encounter of CD4SP cells, and TCR reactivity for self-antigen plays an instructive role in Treg cell differentiation, thereby thymic tolerance mechanisms prevent autoimmunity by restraining the escape of self-reactive effector T cells into the periphery

Cognitive and behavioral effects of lamotrigine and carbamazepine monotherapy in patients with newly diagnosed or untreated partial epilepsy

AbstractPurposeIn this prospective study, we compared the long-term cognitive and behavioral effects of lamotrigine (LTG) and carbamazepine (CBZ) in patients with newly diagnosed or untreated partial epilepsy.MethodsThis was a multicenter, open-label, randomized study that compared monotherapy with LTG and CBZ in newly diagnosed or untreated patients with partial epilepsy. We employed an 8-week titration period and a 40-week maintenance period. Neuropsychological tests, Symptom Check List-90, and QOLIE-31 were assessed at baseline, 16 weeks, and 48 weeks after drug treatment. A group-by-time interaction was the primary outcome measure and was analyzed by use of the linear mixed model.ResultsA total of 110 patients were eligible and 73 completed the 48-week study (LTG, n=39; CBZ, n=34). Among the cognitive tests, significant group-by-time interaction was identified only in phonemic fluency of Controlled Oral Word Association Task (p=0.0032) and Stroop Color–Word Interference (p=0.0283), with a significant better performance for LTG group. All other neuropsychological tests included did not show significant group-by-time interactions. Among the subscales of Symptom Check List-90, significant group-by-time interactions were identified in Obsessive-Compulsive (p=0.0005), Paranoid Ideation (p=0.0454), Global Severity Index (p=0.0194), and Positive Symptom Total (p=0.0197), with a significant improvement for CBZ group. QOLIE-31 did not show significant group-by-time interactions.ConclusionOur data suggest that epilepsy patients on LTG have better performance on phonemic fluency and the task of Stroop Color–Word Interference than do patients on CBZ, whereas patients on CBZ had more favorable behavioral effects on two subscales and two global scores of Symptom Check List-90 than did patients on LTG

An ITAM-signaling pathway controls cross-presentation of particulate but not soluble antigens in dendritic cells

Dendritic cells (DC) possess a unique capacity for presenting exogenous antigen on major histocompatibility class I, a process that is referred to as cross-presentation, which serves a critical role in microbial and tumor immunity. During cross-presentation, antigens derived from pathogen-infected or tumor cells are internalized and processed by DCs for presentation to cytotoxic T lymphocytes (CTLs). We demonstrate that a signaling pathway initiated by the immunoreceptor tyrosine–based activation motif (ITAM)–containing adaptors DAP12 and FcRγ utilizes the Vav family of Rho guanine nucleotide exchange factors (GEFs) for processing and cross-presentation of particulate, but not soluble, antigens by DCs. Notably, this novel pathway is crucial for processing and presentation of particulate antigens, such as those associated with Listeria monocytogenes bacteria, yet it is not required for antigen uptake. Mechanistically, we provide evidence that in DCs, Vav GEFs are essential to link ITAM-dependent receptors with the activation of the NOX2 complex and production of reactive oxygen species (ROS), which regulate phagosomal pH and processing of particulate antigens for cross-presentation. Importantly, we show that genetic disruption of the DAP12/FcRγ–Vav pathway leads to antigen presentation defects that are more profound than in DCs lacking NOX2, suggesting that ITAM signaling also controls cross-presentation in a ROS-independent manner

Successful Chemotherapy Following Autologous Stem Cell Transplantation in Multiple Myeloma and Multi-organ Dysfunction with Infiltration of Eosinophils: A Case Report

Eosinophils are derived from hematopoietic stem cells. Peripheral blood eosinophilia is defined as an absolute eosinophil count of ≥0.5×109/L. Eosinophilia is classified into primary or clonal eosinophilia, secondary eosinophilia, and idiopathic categories including idiopathic hypereosinophilic syndrome. Both hematopoietic and solid neoplasms may be associated with peripheral blood eosinophilia, but multiple myeloma is rarely associated with eosinophilia. We now report the case of a 31-year-old man with multiple myeloma associated with marked eosinophilia who developed multiple organ dysfunction with infiltration of eosinophils. He recovered after treatment with chemotherapy followed by autologous stem cell transplantation

Quadruple 9-mer-based protein binding microarray with DsRed fusion protein

<p>Abstract</p> <p>Background</p> <p>The interaction between a transcription factor and DNA motif (<it>cis</it>-acting element) is an important regulatory step in gene regulation. Comprehensive genome-wide methods have been developed to characterize protein-DNA interactions. Recently, the universal protein binding microarray (PBM) was introduced to determine if a DNA motif interacts with proteins in a genome-wide manner.</p> <p>Results</p> <p>We facilitated the PBM technology using a DsRed fluorescent protein and a concatenated sequence of oligonucleotides. The PBM was designed in such a way that target probes were synthesized as quadruples of all possible 9-mer combinations, permitting unequivocal interpretation of the <it>cis</it>-acting elements. The complimentary DNA strands of the features were synthesized with a primer and DNA polymerase on microarray slides. Proteins were labeled via N-terminal fusion with DsRed fluorescent protein, which circumvents the need for a multi-step incubation. The PBM presented herein confirmed the well-known DNA binding sequences of Cbf1 and CBF1/DREB1B, and it was also applied to elucidate the unidentified <it>cis</it>-acting element of the OsNAC6 rice transcription factor.</p> <p>Conclusion</p> <p>Our method demonstrated PBM can be conveniently performed by adopting: (1) quadruple 9-mers may increase protein-DNA binding interactions in the microarray, and (2) a one-step incubation shortens the wash and hybridization steps. This technology will facilitate greater understanding of genome-wide interactions between proteins and DNA.</p