Extracellular signal-regulated kinase (ERK) activation by the pre-T cell receptor in developing thymocytes in vivo

The first checkpoint in T cell development occurs between the CD4(-)CD8(-) and CD4(+)CD8(+) stages and is associated with formation of the pre-T cell receptor (TCR). The signaling mechanisms that drive this progression remain largely unknown. Here, we show that extracellular signal-regulated kinases (ERKs)-1/2 are activated upon engagement of the pre-TCR. Using a novel experimental system, we demonstrate that expression of the pre-TCR by developing thymocytes induces ERK-1/2 activation within the thymus. In addition, the activation of this pre-TCR signaling cascade is mediated through Lck. These findings directly link pre-TCR complex formation with specific downstream signaling components in vivo.     

Thymic Function and Output of Recent Thymic Emigrant T Cells During Intracranial Glioma Progression

One of the hallmarks of patients with glioblastoma multiforme (GBM) is profound lymphopenia mostly confined to the T cell lineage. A deficiency in the production of naïve T cells from the thymus could contribute to the lymphopenia seen in GBM patients. In this study we asked whether thymic function and the production of recent thymic emigrant (RTE) T cells from the thymus was influenced by intracranial (i.c.) glioma progression. We found significant thymic involution in animals with progressive i.c. gliomas. Involuted thymi from animals with progressive i.c. T9.F gliomas showed dramatic losses of CD4⁺CD8⁺ (DP) thymocytes. Microscopic analysis complemented those findings by demonstrating a reversal of the typical cortico-medullary structure. Significant increases in apoptosis accompanied the rapid loss of viable thymocytes, which was prevented in part by adrenalectomy, suggesting a dominant role for endogenous glucocorticoids. This thymic involution was also associated with a significant decrease in peripheral RTE T cells, reflecting the diminished thymic function. Finally, we found that CD8⁺ RTE T cells were enriched in progressively growing T9 gliomas, which points to an immunological role for RTE's in anti-glioma immunity. Our findings may shed light on the significance of thymic function for anti-glioma immunity and the response to immunotherapeutic treatment paradigms.     

Infantile hemangioendothelioma of the thymus with massive pleural effusion and Kasabach-Merritt syndrome: Histopathological, flow cytometrical analysis of the tumor

Infantile hemangioendothelioma of the thymus is a rare disease. We describe a patient who developed a large anterior mediastinal mass, severe thrombocytopenia and massive pleural effusion at 1 month of age. Glucocorticosteroid and irradiation therapy had no effect on either the tumor size or clinical symptoms and the tumor was resected subtotally. Three months after the subtotal resection, the remaining tumor had almost disappeared and the symptoms had resolved. The patient has now been well for 1 year after surgery without evidence of recurrence. The tumor tissue was characterized by prominent vascular endothelial proliferation intermixed with a normal thymic structure, producing a picture consistent with that of an infantile hemangioendothelioma in the thymus, lmmunohistochemically, the tumor cells showed positive staining for vimentin, factor VIII and CD34. The DNA stemline and proliferative activity were examined by flow cytometry, which revealed a diploid stemline with a low growth fraction. DNA content and cell cycle analyses of the tumor tissue may be useful for predicting the biological behavior of the tumor.     

丝裂霉素与DNA在固体石墨电极上的相互作用研究

应用循环伏安法(CV)研究了药物丝裂霉素(MC)与小牛胸腺DNA(ctDNA)在自制的浸蜡石墨电极上的相互作用。在Na2HPO4NaH2PO4溶液体系中,MC及MCctDNA反应物在电极上出现良好的还原-氧化峰。根据相应的电化学理论方程,由实验数据求得了MC及MCDNA反应复合物的自由扩散系数及反应的表观速率常数。结果表明,固体浸蜡石墨电极可方便、灵敏地用于研究丝裂霉素及与ctDNA相互作用的电化学特性并能用于求取相关参数。     

胸腺肽活性测定方法改进

目的:改进E玫瑰花环试验,用于测定胸腺肽注射液的免疫活性.方法:采用猪血淋巴细胞进行E玫瑰花环试验,以日达仙(Thymosinα1)为对照品,并对试验备件和细节进行分析.结果:对同一批样品进行2次重复试验的结果非常相近.结论:该方法可提高试验的重现性和灵敏度.     

大鼠胸腺内注射MBP诱导免疫耐受对手术SBI引起的脑神经功能缺陷和脑水肿作用研究

为探讨大鼠胸腺内注射髓鞘碱性蛋白(MBP)诱导免疫耐受对手术脑受损(SBI)引起的脑神经功能缺损和脑水肿的影响。选取SD大鼠随机分为假手术组、SBI模型组和MBP处理组,模型组胸腺注射等渗盐水,MBP处理组注射MBP,采用改良神经功能缺陷评分(MNSS)评价各组大鼠神经功能,检测各组大鼠脑水肿体积及血清炎性因子,PCR检测脑组织FasL mRNA表达。结果显示大鼠胸腺内注射MBP诱导免疫耐受,可改善SBI大鼠的脑神经功能缺陷和脑水肿,减轻炎性反应,说明MBP通过诱导免疫耐受,减轻脑受损大鼠的脑神经功能缺陷和脑水肿。     

Effects of growth hormone in enhancing thymic regrowth and T-cell reconstitution

Evaluation of: Napolitano LA, Schmidt D, Gotway MB et al. Growth hormone enhances thymic function in HIV-1-infected adults. J. Clin. Invest. 118, 1085–1098 (2008).

Age-induced atrophy of the thymus results in a compromised immune system characterized by a restricted T-cell receptor repertoire, skewed towards memory T cells and a global reduction in immune responsiveness. This has important clinical implications in immune recovery from lymphopenic states, for example, after cytoablative treatment for cancer therapy, in conditioning regimes for bone marrow transplants and severe viral infections, such as HIV. The paper from Napolitano et al. evaluates the use of growth hormone (GH) to regenerate the thymus and replenish the naive T-cell population for immune recovery in adult HIV patients, albeit those carrying a low viral load. This study – an extension of an earlier paper from the same group – provides important evidence that GH, at least when administered over a long period of time, enhances thymopoiesis and therefore facilitates CD4⁺ T-cell recovery in HIV-1-infected adults. Provided the side effects of GH treatment can be better controlled, these results could contribute towards developing strategies for a broader clinical use of GH in immune recovery.     

Radioprotective effects of black seed (Nigella sativa) oil against hemopoietic damage and immunosuppression in gamma-irradiated rats

Background and aim:?Sixty male Wistar rats, divided into 4 groups, 15 each, were designed as I-control rats, II-rats orally intubated with Nigella sativa oil (1?ml/kg b.wt./day) for 5 days/week, III-whole body gamma irradiated rats with the estimated LD50/30 (4 Gray) and IV-rats daily intubated with Nigella sativa oil then subjected to whole body gamma irradiation, to investigate the radioprotective potential of Nigella crude oil against hemopoietic adverse effects of gamma irradiation.

Results:?Irradiation resulted in significant reduction in hemolysin antibodies titers and delayed type hypersensitivity reaction of irradiated rats, in addition to significant leukopenia and significant decrease in plasma total protein and globulin concentrations and depletion of lymphoid follicles of spleen and thymus gland. Furthermore, there was a significant increase in malondialdehyde concentration with a significant decrease in plasma glutathione peroxidase, catalase and erythrocyte superoxide dismutase activities were recorded. Oral administration of Nigella sativa oil before irradiation considerably normalized all the above-mentioned criteria; and produced significant regeneration in spleen and thymus lymphoid follicles.

Conclusion:?Our results strongly recommend Nigella sativa oil as a promising natural radioprotective agent against immunosuppressive and oxidative effects of ionizing radiation.     

Apoptotic signal transduction and T cell tolerance

The healthy immune system makes use of a variety of surveillance mechanisms at different stages of lymphoid development to prevent the occurrence and expansion of potentially harmful autoreactive T cell clones. Disruption of these mechanisms may lead to inappropriate activation of T cells and the development of autoimmune and lymphoproliferative diseases [such as multiple sclerosis, rheumatoid arthritis, lupus erythematosus, diabetes and autoimmune lymphoproliferative syndrome (ALPS)]. Clonal deletion of T cells with high affinities for self-peptide-MHC via programmed cell death (apoptosis) is an essential mechanism leading to self-tolerance. Referred to as negative selection, central tolerance in the thymus serves as the first checkpoint for the developing T cell repertoire and involves the apoptotic elimination of potentially autoreactive T cells clones bearing high affinity T cell receptors (TCR) that recognize autoantigens presented by thymic epithelial cells. Autoreactive T cells that escape negative selection are held in check in the periphery by either functional inactivation (“anergy”) or extrathymic clonal deletion, both of which are dependent on the strength and frequency of the TCR signal and the costimulatory context, or by regulatory T cells. This review provides an overview of the different molecular executioners of cell death programs that are vital to intrathymic or extrathymic clonal deletion of T cells. Further, the potential involvement of various apoptotic signaling paradigms are discussed with respect to the genesis and pathophysiology of autoimmune disease.     

Alteration of serum thymus and activation‐regulated chemokine level during biologic therapy for psoriasis: Possibility as a marker reflecting favorable response to anti‐interleukin‐17A agents

Biologics show great efficacy in treating psoriasis, a chronic inflammatory skin disease. The high cost and side‐effects of biologics, dose‐reduction, elongation of administration interval and suspension are possible options. However, there has been no reliable biomarker we can use when we consider these moderations in therapy. This study was conducted to test the possibility of using serum thymus and activation‐regulated chemokine (TARC) level as an indicator for step down of biologic therapy. Serum TARC level was measured in 70 psoriatic patients at Asahikawa Medical University, and a correlation of TARC and severity of skin lesions was analyzed. Referring to serum TARC level, psoriatic patients can be divided into two groups. One is a population in which serum TARC level is positively correlated with severity of skin lesions, and the other is a population with low psoriatic severity and high TARC level. Serum TARC level was higher in the group that achieved PASI‐clear with biologics than in the group which did not achieve PASI‐clear. Among biologics, the group treated with secukinumab, an anti‐interleukin (IL)‐17A agent, showed significantly higher TARC level compared with the group treated with anti‐tumor necrosis factor agents. In certain populations achieving PASI‐clear, serum TARC level may be a potent marker reflecting better response to IL‐17A inhibitors, and in this case step down of treatment for psoriasis is possible.