A novel activity on thymocytes cells exerted by the rattlesnake (Crotalus durissus cumanensis) venom / Nueva actividad de los timocitos estimulada por el veneno de la serpiente de cascabel (Crotalus durissus cumanensis)

Abstract. Introduction: The thymus is active mainly during the neonatal and pre-adolescent periods. Objective: To test naïve thymocytes proliferation and monocytes stimulation. Materials and methods: We collected fresh thymus tissue from neonate mice after surgery. Suspension cells were coated onto Ficoll-Hypaque support. The obtained cells (thymocytes) were cultured measuring the proliferation of naïve T cells stimulated by Crotalus durissus cumanensis (Cdc) venom at sub-lethal doses (20 ng). Then, we supplemented the wells with AlamarBlue™ and incubated them for 5 h to test their proliferation. Mononuclear cells from mice peripheral blood were collected and layered onto the support of the Ficoll-Hypaque solution. We added the thymocytes actively dividing (25 x 105 cells) from cultures stimulated with Cdc venom at 20 ng/well to cultured monocytes freshly obtained from the Ficoll-Hypaque separation. Both cell populations were incubated for 36 h until monocytes matured to macrophages. Results: The naïve thymocytes rapidly proliferated after stimulation with the Cdc venom (NTCdc) and these successively induced the maturation and function of monocytes progenitor cells to mature macrophages, which ingested Chinese ink. Conclusions: The naïve thymocytes proliferated by stimulation with the Cdc venom and subsequently the NT/Cdc induced the rapid maturation and function of monocytes progenitor cells becoming mature macrophages with their phenotypic characteristics.

Resumen. Introducción. El timo es activo principalmente durante los períodos neonatal y preadolescente. Objetivo. Probar la proliferación de los timocitos tempranos y la estimulación de monocitos que producen. Materiales y métodos. Se recogió tejido de timo fresco después de la cirugía de ratones recién nacidos. La suspensión de células se colocó sobre un soporte de Ficoll-Hypaque. Las células obtenidas (timocitos) se cultivaron y se midió la proliferación de células T vírgenes estimuladas por el veneno de Crotalus durissus cumanensis (Cdc) en dosis subletales (20 ng). A continuación, se agregó AlamarBlue™ a los pocillos y se incubaron durante 5 horas para evaluar la proliferación. Se recogieron células mononucleares de sangre periférica de ratones y se colocaron sobre un soporte de solución de Ficoll-Hypaque. Los timocitos que se dividieron activamente (25 x 105 células) a partir de los cultivos estimulados con veneno de Cdc (20 ng/pocillo) y se agregaron a los cultivos de monocitos recién obtenidos de la separación en la solución de Ficoll-Hypaque. Ambas poblaciones celulares se incubaron durante 36 horas hasta que los monocitos maduraron a macrófagos. Resultados Los timocitos tempranos experimentaron una rápida proliferación estimulada por el veneno de Cdc (NTCdc) y, posteriormente, indujeron la maduración y la función de las células progenitoras de monocitos, los cuales maduraron a macrófagos, que se tiñeron con tinta china. Conclusiones. Los timocitos tempranos proliferaron con la estimulación del veneno de Cdc y, posteriormente, el NT/Cdc indujo la maduración rápida y la función de las células progenitoras de monocitos, transformándose en macrófagos con sus características fenotípicas.

Alterations in thymocyte populations under conditions of endotoxin tolerance / 中华医学杂志(英文版)

BACKGROUND@#Endotoxin tolerance (ET) is a protective phenomenon in which pre-treatment with a tolerance dose of lipopolysaccharide (LPS) leads to dramatically elevated survival. Accumulating evidence has shown that peripheral T cells contribute to the induction of ET. However, what happens to T cell development in the thymus under ET conditions remains unclear. The purpose of this study was to analyze the alterations in thymocyte populations (double-positive [DP] and single-positive [SP] cells) under ET conditions.@*METHODS@#Mice were intraperitoneally injected with LPS at a concentration of 5 mg/kg to establish an LPS tolerance model and were divided into two groups: a group examined 72 h after LPS injection (72-h group) and a group examined 8 days after LPS injection (8-day group). Injection of phosphate-buffered saline was used as a control (control group). Changes in thymus weight, cell counts, and morphology were detected in the three groups. Moreover, surface molecules such as CD4, CD8, CD44, CD69, and CD62L were analyzed using flow cytometry. Furthermore, proliferation, apoptosis, cytokine production, and extracellular signal-regulated kinase (ERK) pathway signaling were analyzed in thymocyte populations. The polymorphism and length of the T-cell receptor (TCR) β chain complementarity-determining region 3 (CDR3) were analyzed using capillary electrophoresis DNA laser scanning analysis (ABI 3730).@*RESULTS@#Thymus weight and cell counts were decreased in the early stage but recovered by the late stage in a murine model of LPS-induced ET. Moreover, the proportions of DP cells (control: 72.130 ± 4.074, 72-h: 10.600 ± 3.517, 8-day: 84.770 ± 2.228), CD4+ SP cells (control: 15.770 ± 4.419, 72-h: 44.670 ± 3.089, 8-day: 6.367 ± 0.513), and CD8+ SP cells (control: 7.000 ± 1.916, 72-h: 34.030 ± 3.850, 8-day: 5.133 ± 0.647) were obviously different at different stages of ET. The polymorphism and length of TCR β chain CDR3 also changed obviously, indicating the occurrence of TCR rearrangement and thymocyte diversification. Further analysis showed that the expression of surface molecules, including CD44, CD69, and CD62L, on thymocyte populations (DP and SP cells) were changed to different degrees. Finally, the proliferation, apoptosis, cytokine production, and ERK pathway signaling of thymocyte populations were changed significantly.@*CONCLUSION@#These data reveal that alterations in thymocyte populations might contribute to the establishment of ET.

CD24⁺ Cell Depletion Permits Effective Enrichment of Thymic iNKT Cells While Preserving Their Subset Composition

Invariant NKT (iNKT) cells are a small subset of thymus-generated T cells that produce cytokines to control both innate and adaptive immunity. Because of their very low frequency in the thymus, in-depth characterization of iNKT cells can be facilitated by their enrichment from total thymocytes. Magnetic-activated cell sorting (MACS) of glycolipid antigen-loaded CD1d-tetramer-binding cells is a commonly used method to enrich iNKT cells. Surprisingly, we found that this procedure also dramatically altered the subset composition of enriched iNKT cells. As such, NKT2 lineage cells that express large amounts of the transcription factor promyelocytic leukemia zinc finger were markedly over-represented, while NKT1 lineage cells expressing the transcription factor T-bet were significantly reduced. To overcome this limitation, here, we tested magnetic-activated depletion of CD24⁺ immature thymocytes as an alternative method to enrich iNKT cells. We found that the overall recovery in iNKT cell numbers did not differ between these 2 methods. However, enrichment by CD24⁺ cell depletion preserved the subset composition of iNKT cells in the thymus, and thus permitted accurate and reproducible analysis of thymic iNKT cells in further detail.

Polyclonal anti T-lymphocyte antibody therapy monitoring in kidney transplant recipients: comparison of CD3+ T cell and total lymphocyte counts / Monitoramento da terapia com anticorpo policlonal antilinfócitos T em transplantados renais: comparação da contagem de células T CD3+ e de linfócitos totais

ABSTRACT Objective: To investigate the correlation between total lymphocyte and CD3+ T cell counts in peripheral blood in renal transplant patients treated with anti-thymocyte globulin, and discuss related outcomes. Methods: A single-center, retrospective study involving 226 patients submitted to kidney transplant between 2008 and 2013, and treated with anti-thymocyte globulin for induction or treatment of cellular rejection. Doses were adjusted according to CD3+ T cell or total lymphocyte counts in peripheral blood. Results: A total of 664 paired samples were analyzed. The Spearman's correlation coefficient was 0.416 (p<0.001) for all samples combined; the overall Kappa coefficient was 0.267 (p<0.001). Diagnostic parameters estimated based on total lymphocyte counts were also calculated using the number of CD3+ T cells (gold standard), with a cut off of >20 cells/mm3. Conclusion: Total lymphocyte and CD3+ T cell counts in peripheral blood are not equivalent monitoring strategies in anti-thymocyte globulin therapy.

RESUMO Objetivo: Investigar a correlação entre a contagem de linfócitos totais e células T CD3+ no sangue periférico em receptores de transplante renal submetidos a tratamento com globulina antitimocitária, e discutir resultados relacionados. Métodos: Estudo retrospectivo de centro único envolvendo 226 pacientes submetidos a transplante renal entre 2008 e 2013 e tratados com globulina antitimocitária, para fins de indução ou tratamento de rejeição celular. As doses foram ajustadas de acordo com a contagem de células T CD3+ ou linfócitos totais no sangue periférico. Resultados: No total, 664 amostras pareadas foram analisadas. O coeficiente de correlação de Spearman para as amostras em geral foi de 0,416 (p<0,001) e o coeficiente Kappa, de 0,267 (p<0,001). Os parâmetros diagnósticos estimados com base na contagem de linfócitos totais foram recalculados, empregando-se o número de células T CD3+ (padrão-ouro) e adotando-se o ponto de corte >20 células/mm3. Conclusão: A contagem de linfócitos totais no sangue periférico não substitui a contagem de células T CD3+ enquanto estratégia de monitorização da terapia à base de globulina antitimocitária.

T Cell's Sense of Self: a Role of Self-Recognition in Shaping Functional Competence of Naïve T Cells

Post-thymic naïve T cells constitute a key cellular arm of adaptive immunity, with a well-known characteristic of the specificity and robustness of responses to cognate foreign antigens which is presented as a form of antigen-derived peptides bound to major histocompatibility complex (MHC) molecules by antigen-presenting cells (APCs). In a steady state, however, these cells are resting, quiescent in their activity, but must keep full ranges of functional integrity to mount rapid and robust immunity to cope with various infectious pathogens at any time and space. Such unique property of resting naïve T cells is not acquired in a default manner but rather requires an active mechanism. Although our understanding of exactly how this process occurs and what factors are involved remains incomplete, a particular role of self-recognition by T cells has grown greatly in recent years. In this brief review, we discuss recent data on how the interaction of T cells with self-peptide MHC ligands regulates their functional responsiveness and propose that variable strength of self-reactivity imposes distinctly different levels of functional competence and heterogeneity.

Growth hormone in the presence of laminin modulates interaction of human thymic epithelial cells and thymocytes in vitro

BACKGROUND: Several evidences indicate that hormones and neuropeptides function as immunomodulators. Among these, growth hormone (GH) is known to act on the thymic microenvironment, supporting its role in thymocyte differentiation. The aim of this study was to evaluate the effect of GH on human thymocytes and thymic epithelial cells (TEC) in the presence of laminin. RESULTS: GH increased thymocyte adhesion on BSA-coated and further on laminin-coated surfaces. The number of migrating cells in laminin-coated membrane was higher in GH-treated thymocyte group. In both results, VLA-6 expression on thymocytes was constant. Also, treatment with GH enhanced laminin production by TEC after 24 h in culture. However, VLA-6 integrin expression on TEC remained unchanged. Finally, TEC/thymocyte co-culture model demonstrated that GH elevated absolute number of double-negative (CD4-CD8-) and single-positive CD4+ and CD8+ thymocytes. A decrease in cell number was noted in double-positive (CD4+CD8+) thymocytes. CONCLUSIONS: The results of this study demonstrate that GH is capable of enhancing the migratory capacity of human thymocytes in the presence of laminin and promotes modulation of thymocyte subsets after co-culture with TEC.

The Anti-apoptotic Effect of Ghrelin on Restraint Stress-Induced Thymus Atrophy in Mice

Thymic atrophy is a complication that results from exposure to many environmental stressors, disease treatments, and microbial challenges. Such acute stress-associated thymic loss can have a dramatic impact on the host's ability to replenish the necessary naïve T cell output to reconstitute the peripheral T cell numbers and repertoire to respond to new antigenic challenges. We have previously reported that treatment with the orexigenic hormone ghrelin results in an increase in the number and proliferation of thymocytes after dexamethasone challenge, suggesting a role for ghrelin in restraint stress-induced thymic involution and cell apoptosis and its potential use as a thymostimulatory agent. In an effort to understand how ghrelin suppresses thymic T cell apoptosis, we have examined the various signaling pathways induced by receptor-specific ghrelin stimulation using a restraint stress mouse model. In this model, stress-induced apoptosis in thymocytes was effectively blocked by ghrelin. Western blot analysis demonstrated that ghrelin prevents the cleavage of pro-apoptotic proteins such as Bim, Caspase-3, and PARP. In addition, ghrelin stimulation activates the Akt and Mitogen-activated protein kinases (MAPK) signaling pathways in a time/dose-dependent manner. Moreover, we also revealed the involvement of the FoxO3a pathway in the phosphorylation of Akt and ERK1/2. Together, these findings suggest that ghrelin inhibits apoptosis by modulating the stress-induced apoptotic signal pathway in the restraint-induced thymic apoptosis.

Modulação da expressão gênica no timo: uma perspectiva integrativa da regulação gênica no desenvolvimento de timócitos e involução tímica decorrente de infecção / Gene expression modulation in thymus: an integrative perspective of the gene regulation during thymocyte development and thymic involution due to infection

O timo é um órgão linfoide primário no qual ocorre o desenvolvimento de células T. Distúrbios nesse processo podem levar a doenças diversas inclusive à autoimunidade. [...] Nesse sentido, essa tese aborda os aspectos moleculares envolvidos na linfopoiese T sob a perspectiva das células progenitoras e das TEC. Nosso estudod e meta-análise utilizando microarranjos de timócitos em estágios de desenvolvimento definidos pela expressão de moléculas CD4 e CD8 permitiu a identificação de 14 agrupamentos gênicos,os quais se relacionam intimamente às etapas do desenvolvimento dessas células. A modulaçãodesses genes está vinculada à sinalização via receptor de células T (TCR) e pode sercorrelacionada com a afinidade pelo complexo formado entre peptídeo e o complexo principal dehistocompatibilidade (MHC). Destacam-se ainda, vias de sinalização relacionadas a outrosreceptores de superfície, evidenciando a importância dos estímulos externos no desenvolvimentode células T. Através da integração de dados, nós identificamos as vias e moléculas com maiorimpacto para a diferenciação de timócitos, bem como complementamos a compreensão de comoos eventos envolvidos nesse processo se organizam temporalmente, apresentando umaperspectiva global das ondas de modulação gênica. Já em outra perspectiva, estudamos aregulação gênica em TEC comparando células corticais e medulares, mas também focamos nainvolução tímica, uma resposta natural a diversas fontes de estresse e ao envelhecimento.Nessa tese, esse fenômeno foi estudado em modelos experimentais de fase aguda da doençade Chagas, pois existem evidências de que as alterações no timo durante a fase aguda podemser responsáveis pelo desfecho da doença anos mais tarde...

The thymus is a primary lymphoid organ, where the T cell development takes place. Disturbanceson this process can lead to a diversity of diseases, including autoimmunity. [...] In this sense, this thesis addresses the molecular aspects involved on Tlymphopoiesis under the progenitor cells and TEC perspective. Our meta-analysis study usingmicroarrays of thymocytes sorted based on the developmental stages defined by the CD4 andCD8 expression allowed to identify 14 gene clusters, which are closely related to thedevelopmental stages of these cells. Those genes modulation is linked to the T cell receptor(TCR) signaling pathway and it can be related to the TCR affinity for the complex formed betweenthe peptide and the major histocompatibility complex (MHC). Moreover, other signaling pathwaysrelated to surface receptors stand out, highlighting the importance of external stimuli on the T celldevelopment. Through data integration, we identify pathways and molecules that have morerelevant impact on the thymocyte differentiation, as well as, we improved the comprehension onhow the events are organized temporally, providing a global perspective on the gene modulationwaves. In another perspective, we have studied the gene regulation on TEC by comparingcortical and medullary cells, but also focused on thymic involution, a natural response to varioussources of stress and aging. In this thesis, this phenomenon was studied using Chagas' diseaseacute phase experimental model because there are evidences showing that the thymic alterationsduring the acute phase can be responsible for the disease outcome years later...

Selection of Thymocytes Expressing Transgenic TCR Specific for a Minor Histocompatibility Antigen, H60

Minor histocompatibility antigens are MHC-bound peptides and contribute to the generation of allo-responses after allogeneic transplantation. H60 is a dominant minor H antigen that induces a strong CD8 T-cell response in MHC-matched allogeneic transplantation settings. Here, we report establishment of a TCR transgenic mouse line named J15, wherein T cells express TCRs specific for H60 in complex with H-2K(b), and different fates of the thymocytes expressing J15 TCRs in various thymic antigenic environments. Thymocytes expressing the J15 TCRs were positively selected and differentiated into CD8+ single positive (SP) cells in the thymus of C57BL/6 mice, wherein the cognate antigen H60 is not expressed. However, thymocytes were negatively selected in thymus tissue where H60 was transgenically expressed under the control of the actin promoter, with double-positive stages of cells being deleted. Despite the ability of the H60H peptide (LTFHYRNL) variant to induce cytotoxic activity from H60-specific CTL lines at ~50% of the activity induced by normal H60 peptides (LTFNYRNL), J15-expressing thymocytes were positively selected in the thymus where the variant H60H was transgenically expressed. These results demonstrate that a single amino-acid change in the H60 epitope peptide influences the fate of thymocytes expressing the cognate TCR.

Analyses of the TCR repertoire of MHC class II-restricted innate CD4+ T cells

Analysis of the T-cell receptor (TCR) repertoire of innate CD4+ T cells selected by major histocompatibility complex (MHC) class II-dependent thymocyte-thymocyte (T-T) interaction (T-T CD4+ T cells) is essential for predicting the characteristics of the antigens that bind to these T cells and for distinguishing T-T CD4+ T cells from other types of innate T cells. Using the TCRmini Tg mouse model, we show that the repertoire of TCRalpha chains in T-T CD4+ T cells was extremely diverse, in contrast to the repertoires previously described for other types of innate T cells. The TCRalpha chain sequences significantly overlapped between T-T CD4+ T cells and conventional CD4+ T cells in the thymus and spleen. However, the diversity of the TCRalpha repertoire of T-T CD4+ T cells seemed to be restricted compared with that of conventional CD4+ T cells. Interestingly, the frequency of the parental OT-II TCRalpha chains was significantly reduced in the process of T-T interaction. This diverse and shifted repertoire in T-T CD4+ T cells has biological relevance in terms of defense against diverse pathogens and a possible regulatory role during peripheral T-T interaction.

The Role of Dendritic Cells in Central Tolerance

Dendritic cells (DCs) play a significant role in establishing self-tolerance through their ability to present self-antigens to developing T cells in the thymus. DCs are predominantly localized in the medullary region of thymus and present a broad range of self-antigens, which include tissue-restricted antigens expressed and transferred from medullary thymic epithelial cells, circulating antigens directly captured by thymic DCs through coticomedullary junction blood vessels, and peripheral tissue antigens captured and transported by peripheral tissue DCs homing to the thymus. When antigen-presenting DCs make a high affinity interaction with antigen-specific thymocytes, this interaction drives the interacting thymocytes to death, a process often referred to as negative selection, which fundamentally blocks the self-reactive thymocytes from differentiating into mature T cells. Alternatively, the interacting thymocytes differentiate into the regulatory T (Treg) cells, a distinct T cell subset with potent immune suppressive activities. The specific mechanisms by which thymic DCs differentiate Treg cells have been proposed by several laboratories. Here, we review the literatures that elucidate the contribution of thymic DCs to negative selection and Treg cell differentiation, and discusses its potential mechanisms and future directions.

Fibronectin modulates thymocyte-thymic epithelial cell interactions following Trypanosoma cruzi infection

Developing thymocytes interact with thymic epithelial cells (TECs) through cell-cell interactions, TEC-derived secretory moieties and extracellular matrix (ECM)-mediated interactions. These physiological interactions are crucial for normal thymocyte differentiation, but can be disrupted in pathological situations. Indeed, there is severe thymic atrophy in animals acutely infected with Trypanosoma cruzi due to CD4+CD8+ thymocyte depletion secondary to caspase-mediated apoptosis, together with changes in ECM deposition and thymocyte migration. We studied an in vitro model of TEC infection by T. cruzi and found that infected TEC cultures show a reduced number of cells, which was likely associated with decreased proliferative capacity, but not with increased cell death, as demonstrated by bromodeoxyuridine and annexin-V labelling. The infected TEC cultures exhibited increased expression of fibronectin (FN), laminin (LM) and type IV collagen. Importantly, treatment with FN increased the relative number of infected cells, whereas treatment with anti-FN or anti-LM antibodies resulted in lower infection rates. Consistent with these data, we observed increased thymocyte adhesion to infected TEC cultures. Overall, these results suggest that ECM molecules, particularly FN, facilitate infection of the thymic epithelium and that the consequent enhancement of ECM expression might be associated with changes in TEC-thymocyte interactions.

Thymic epithelial cell development and differentiation: cellular and molecular regulation

Thymic epithelial cells (TECs) are one of the most important components in thymic microenvironment supporting thymocyte development and maturation. TECs, composed of cortical and medullary TECs, are derived from a common bipotent progenitor, mediating thymocyte positive and negative selections. Multiple levels of signals including intracellular signaling networks and cell-cell interaction are required for TEC development and differentiation. Transcription factors Foxn1 and autoimmune regulator (Aire) are powerful regulators promoting TEC development and differentiation. Crosstalks with thymocytes and other stromal cells for extrinsic signals like RANKL, CD40L, lymphotoxin, fibroblast growth factor (FGF) and Wnt are also definitely required to establish a functional thymic microenvironment. In this review, we will summarize our current understanding about TEC development and differentiation, and its underlying multiple signal pathways.

Effect of glucocorticoids on surface IL-10 receptors and intracellular IL-10 in mouse splenocytes, thymocytes, monocytes, and dendritic cells: immunofluorescence, confocal microscopy, and electrophoresis study

Glucocorticoids are capable of stimulating the secretion of interleukin -10 [IL-10] by leukocytes. The probable role of glucocorticoids in the susceptibility of immune cells to IL-10 mediated actions has not yet been studied. In this study, we examine the expression of IL-10 and IL-10 receptors [IL-1OR] in mouse splenocytes, thymocytes, monocytes, and dendritic cells. In addition, we determined the effects of the glucocorticoid [methylprednisolone] on IL-10 secretion and IL-10R expression in the previous immune cells. Forty-eight male mice with the C57BL/6 genetic background were used. The animals were 10-12 weeks of age and were divided equally into two groups. The animals in group I were provided with a balanced standard diet and water ad libitum. The animals in group II were provided with a balanced standard diet and methylprednisolone [o.5mg/kg/day] in the drinking water daily for 7 days. The mice in groups I and II were sacrificed after 7 days and the spleen and thymun were removed to isolate the splenocytes and thymocytes. The blood was also aspirated to isolate monocytes. Group III included mice with the mouse dendritic cell line [JAWS II]. Cells of the mice in this group were divided into two subgroups. Group IIIa included the dendritic cells cultured in Iscove's modified Dulbecco's medium and group IIIb included the dendritic cells cultured in Iscove's modified Dulbecco's medium supplemented with methylprednisolone [2micro g/ml] for 6h. All the previous cells were processed for immunohistochemistry, western blotting, immunoassay analysis, and electrophoresis. All the cells examined showed an intense fluorescent surface expression of IL-10R as detected by the immunofluorescence technique. On using methylprednisolone, there were few and faint expressions of IL-1OR. The intracellular IL-10 molecules were few in the dendritic cells but after treatment with methylprednisolone, the IL-10 molecules were numerous and intense. Western blotting and electrophoresis techniques showed intense precipitation of IL-10 at 35 kDa and faint precipitation of IL-10R at 110kDa in all the cells examined after glucocorticoid treatment. There was also a highly significant [P<0.001] increase in the level of IL-10 in all the cells examined after using methylprednisolone as detected by immunoassay. Our findings could contribute toward understanding the immunomodulating mechanism of the action of glucocorticoids, which may result in greater therapeutic benefit in some diseases by enhancing the synthesis of the anti-inflammatory cytokine IL-10 and decreasing the expression of IL-1OR in some immune cells

Effects of huqi extractum on the viability and apoptosis in mouse thymic lymphocytes against 60Co radiation / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To explore the effects of Huqi Extractum (HQE) on the viability and apoptosis in mouse thymic lymphocytes against 60Co radiation.</p><p><b>METHODS</b>Thymic lymphocytes were isolated from 4 -8 weeks healthy male Kunming mice and primarily cultured. Then they were divided into the control group, the irradiation group, the low dose HQE group, the medium dose HQE group, and the high dose HQE group. Equal volume of serum free RPMI-1640 culture solution was added in the control group and the irradiation group, while equal volume of HQE solution (at the daily dose of 25, 50, and 100 mg/mL) was respectively added in the low, medium, and high dose HQE groups. Except the control group, those in the rest groups were exposed radiation at a single dose of 5 Gy gamma-ray. Changes of the thymic lymphocytes' viability were measured by MTT colorimetric assay at 12, 24, 36, and 48 h after radiation. The early apoptosis rate was detected using flow cytometry (FCM) after 10-h radiation. The apoptosis was detected using agarose gel electrophoresis to observe the DNA injury after 24-h radiation.</p><p><b>RESULTS</b>The viability level decreased more obviously in the irradiation group than in the control group at 24 -48 h after radiation (P < 0.01, P < 0.05). The average viability level was obviously higher in the low, medium, and high dose HQE groups than in the irradiation group (P < 0.05) in a dose dependent manner. The early apoptosis rate was obviously lower in the low, medium, and high dose HQE groups than in the irradiation group, with statistical difference shown in the high dose HQE group (P < 0.01). Typical DNA ladder fragments were found in the electrophoresis in all groups except the control group. But the DNA injury was comparatively milder in the low, medium, and high dose HQE groups, with more obvious effects shown in the high dose HQE group.</p><p><b>CONCLUSION</b>HQE showed protection for the viability of early thymic lymphocytes exposed to the 60CO radiation, and could lower the early apoptosis level.</p>

Methylmercury Exposure and Health Effects / 예방의학회지

Methylmercury is a hazardous substance that is of interest with regard to environmental health, as inorganic mercury circulating in the general environment is dissolved into freshwater and seawater, condensed through the food chain, ingested by humans, and consequently affects human health. Recently, there has been much interest and discussion regarding the toxicity of methylmercury, the correlation with fish and shellfish intake, and methods of long-term management of the human health effects of methylmercury. What effects chronic exposure to a low concentration of methylmercury has on human health remains controversial. Although the possibility of methylmercury poisoning the heart and blood vessel system, the reproductive system, and the immune system is continuously raised and discussed, and the carcinogenicity of methylmercury is also under discussion, a clear conclusion regarding the human health effects according to exposure level has not yet been drawn. The Joint FAO/WHO Expert Committee on Food Additives proposed to prepare additional fish and shellfish intake recommendations for consumers based on the quantified evaluation of the hazardousness of methylmercury contained in fish and shellfish, methylmercury management in the Korea has not yet caught up with this international trend. Currently, the methylmercury exposure level of Koreans is known to be very high. The starting point of methylmercury exposure management is inorganic mercury in the general environment, but food intake through methylation is the main exposure source. Along with efforts to reduce mercury in the general environment, food intake management should be undertaken to reduce the human exposure to methylmercury in Korea.

Effects and mechanisms of Cryptotanshinone on rats with adjuvant arthritis / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Cryptotanshinone (CT) is the major active constituent of Salvia miltiorrhiza Bunge. The present study was carried out to investigate the effects of CT on rats with adjuvant arthritis (AA).</p><p><b>METHODS</b>AA was induced by the metatarsal footpad injection with complete Freund's adjuvant in male Sprague-Dawley rats. The secondary inflammatory reaction was evaluated by hind paw swelling and the polyarthritis index. Activity of interleukin-1 (IL-1) was detected by the concanavalin A-induced thymocytes proliferation assay. The lymphocytes proliferation and IL-2 production were assayed by 3-(4,5-2dimethylthiazal-2yl)2,5-diphenyltetrazoliumbromide (MTT) and activated mouse splenocytes proliferation, respectively.</p><p><b>RESULTS</b>Intragastric administration of CT (50 and 100 mg/kg) significantly decreased secondary inflammatory reactions and increased the spleen and thymus index. There was a marked immunologic and inflammatory response in the AA model, which was accompanied by the decrease of thymocyte proliferation and IL-2 production as well as the increase of IL-1 production. CT apparently enhanced thymocyte proliferation and decreased IL-1 production in AA rats.</p><p><b>CONCLUSION</b>These results indicate that CT may exert its anti-inflammatory and immunoregulatory effects through inhibiting lymphocyte proliferation and production of pro-inflammatory mediators.</p>

Expression of IL-17A during Thymus Regeneration in the Rat / 체질인류학회지

IL-17A is a pro-inflammatroy cytokine secreted by activated T cells. The IL-17 family consist of IL-17A, IL-17B, IL-17C, IL-17D, IL-17E and IL-17F. IL-17A and IL-17F are produced primarily in activated T cells. In contrast, IL-17B, IL-17C, IL-17D and IL-17E are expressed in a wide assortment of tissues. Their functions partially overlap those of IL-17A, although they have not been as thoroughly investigated. The receptor for IL-17A (IL-17R) is widely expressed in a variety of tissues. IL-17A and IL-17E mRNAs were expressed in only EL4 cells. IL-17C mRNA expression was observed in the thymic subcapsular/cortex epithelial cells (SNEC), cortex or cortical reticular cells (CREC), medullary epithelial cells (MEC), medullary interdigitating-like cells (MDC), thymocytes and EL4 cells. However, IL-17C mRNA was not expressed in RAW 264.7 cells. Immunohistochemical study also demonstrated not only the presence of IL-17A mainly in the thymic epithelial cells, but also the upregulated expression of IL-17A in the thymic epithelial cells of the regenerating thymus. Thus, the results of the present study suggest that IL-17A expressed in the thymocytes and thymic epithelial cells could play an important role in the development of new T cells to replace T cells damaged by cyclophosphamide treatment during thymus regeneration.

Characterization of Monoclonal Antibodies against Human Leukocyte Common Antigen (CD45)

BACKGROUND: The leukocyte common antigen (CD45) is a transmembrane-type protein tyrosine phosphatase that has five isoforms. METHODS: We generated seven murine mAbs against human CD45 by injecting cells from different origins, such as human thymocytes, PBMCs, and leukemic cell lines. By using various immunological methods including flow cytometry, immunohistochemistry, and immunoprecipitation, we evaluated the reactivity of those mAbs to CD45 of thymus as well as tonsil lysates. Furthermore, we transiently transfected COS-7 cells with each of gene constructs that express five human CD45 isoforms respectively, and examined the specificities of the mAbs against the transfected isoforms. RESULTS: In case of thymocytes, lymphocytes, and monocytes, all the seven mAbs demonstrated positive reactivities whereas none was reactive to erythrocytes and platelets. The majority of immune cells in formalin-fixed paraffin-embedded thymus and tonsil tissues displayed strong membranous immunoreactivity, and the main antigen was detected near 220 kDa in all cases. Among the mAbs, four mAbs (AP4, DN11, SHL-1, and P6) recognized a region commonly present in all the five isoforms. One mAb, YG27, recognized four isoforms (ABC, AB, BC, and O). Two mAbs, P1 and P14, recognized the isoforms that contain exon A encoded regions (ABC and AB). CONCLUSION: In this study, we confirmed that AP4, DN11, SHL-1, YG27 and P6, are mAbs reactive with the CD45 antigen whereas P1 and P14 are reactive with the CD45RA antigen.

Effect of G-CSF on murine thymocyte emigration and cell cycle alteration after a sublethal dose of irradiation / 中国实验血液学杂志

This study was aimed to investigate the effect of recombinant human granulocyte colony-stimulating factor(G-CSF) on murine thymocyte emigration and cell cycle alteration after a sublethal dose of gamma-irradiation. Female BALB/c mice were given 6.0 Gy γ-ray total body irradiation and then randomly divided into G-CSF and control groups. Mice in the G-CSF group were injected recombinant human G-CSF 100 µg/(kg·d) subcutaneously once daily for 14 consecutive days and mice in the control group were given the same volume of phosphate buffered solution. Thymocyte cycle alteration and the proportion of apoptosis cells were detected by flow cytometry within 72 hours after irradiation. Real-time PCR was used for detection and quantitation of murine T cell receptor rearrangement excision circles (sjTREC) of the thymic cells at 30 and 60 day after the irradiation. The results showed that at 6 hour after irradiation G-CSF could significantly increase the thymic cells in G(0)/G(1) phase, G-CSF vs control: (82.0 ± 5.0)% vs (75.9 ± 2.8)% (p < 0.05), and decrease the thymic cells in S phase, G-CSF vs control: (10.2 ± 4.8)% vs (15.7 ± 2.3)% (p < 0.05), but G-CSF seemed have no evident effects on the percentage of thymic cells in G(2)/M phase. G-CSF could also protect thymocytes from apoptosis at 6 hour and 12 hour after irradiation the percentages of apoptosis cells in G-CSF group were (11.5 ± 2.4)% and (15.5 ± 3.3)%, respectively, which were significantly lower than that of the control group (16.5 ± 2.2)% and (22.6 ± 0.7)%, respectively (p < 0.05). The sjTREC copy amount was conspicuously higher in G-CSF group than that in the control at 30 day after irradiation (p < 0.01), but the preponderance disappeared 60 days later. It is concluded that G-CSF has a positive effect on the thymic cell cycle alteration to protect thymocytes from apoptosis and enhance the recent thymocyte emigration, which may contribute to the central immune reconstitution after irradiation.