Dose and dose rate effects of whole-body proton-irradiation on lymphocyte blastogenesis and hematological variables: part II.

The goal of part II of this study was to evaluate functional characteristics of leukocytes and circulating blood cell parameters after whole-body proton irradiation at varying doses and at low- and high-dose-rates (LDR and HDR, respectively). C57BL/6 mice (n=51) were irradiated and euthanized at 4 days post-exposure for assay. Significant radiation dose- (but not dose-rate-) dependent decreases were observed in splenocyte responses to T and B cell mitogens when compared to sham-irradiated controls (P<0.001). Spontaneous blastogenesis, also significantly dose-dependent, was increased in both blood and spleen (P<0.001). Red blood cell counts, hemoglobin concentration, and hematocrit were decreased in a dose-dependent manner (P<0.05), whereas thrombocyte numbers were only slightly affected. Comparison of proton- and gamma-irradiated groups (both receiving 3 Gy at HDR) showed a higher level of spontaneous blastogenesis in blood leukocytes and a lower splenocyte response to concanavalin A following proton irradiation (P<0.05). There were no dose rate effects. Collectively, the data demonstrate that the measurements in blood and spleen were largely dependent upon the total dose of proton radiation and that an 80-fold difference in the dose rate was not a significant factor. A difference, however, was found between protons and gamma-rays in the degree of change induced in some of the measurements.     

Genotoxic effects of high dose rate X‐ray and low dose rate gamma radiation in ApcMin/+ mice

Risk estimates for radiation‐induced cancer in humans are based on epidemiological data largely drawn from the Japanese atomic bomb survivor studies, which received an acute high dose rate (HDR) ionising radiation. Limited knowledge exists about the effects of chronic low dose rate (LDR) exposure, particularly with respect to the application of the dose and dose rate effectiveness factor. As part of a study to investigate the development of colon cancer following chronic LDR vs. acute HDR radiation, this study presents the results of genotoxic effects in blood of exposed mice. CBAB6 F1 Apc^+/+ (wild type) and Apc^Min/+ mice were chronically exposed to estimated whole body absorbed doses of 1.7 or 3.2 Gy ⁶⁰Co‐γ‐rays at a LDR (2.2 mGy h^?1) or acutely exposed to 2.6 Gy HDR X‐rays (1.3 Gy min^?1). Genotoxic endpoints assessed in blood included chromosomal damage (flow cytometry based micronuclei (MN) assay), mutation analyses (Pig‐a gene mutation assay), and levels of DNA lesions (Comet assay, single‐strand breaks (ssb), alkali labile sites (als), oxidized DNA bases). Ionising radiation (ca. 3 Gy) induced genotoxic effects dependent on the dose rate. Chromosomal aberrations (MN assay) increased 3‐ and 10‐fold after chronic LDR and acute HDR, respectively. Phenotypic mutation frequencies as well as DNA lesions (ssb/als) were modulated after acute HDR but not after chronic LDR. The Apc^Min/+ genotype did not influence the outcome in any of the investigated endpoints. The results herein will add to the scant data available on genotoxic effects following chronic LDR of ionising radiation. Environ. Mol. Mutagen. 58:560–569, 2017. © 2017 The Authors Environmental and Molecular Mutagenesis published by Wiley Periodicals, Inc. on behalf of Environmental Mutagen Society     

Absolute values of dendritic cell subsets in bone marrow,cord blood,and peripheral blood enumerated by a novel method

Dendritic cells (DCs) are pivotal in inducing immunity or alternatively downregulating immune reactivity. In humans, the opposing phenotypic subsets of CD11c(+)/CD123(-) "myeloid" DCs and CD123(+)/CD11c(-) "lymphoid" DCs have been proposed to orchestrate these immune responses. In this study we determined the absolute numbers of both subsets in three resting hematopoietic tissues by employing a novel flow cytometry method, eliminating processing steps and calculations based on mononuclear cell percentages. Internal bead standards along with the cells of interest were simultaneously acquired directly from unmanipulated whole blood specimens. We found significant differences (p < 0.001) between the mean absolute numbers of CD123(+)/CD11c(-) lymphoid DCs among the three sources, with the fewest present in peripheral blood (8.2/ micro l), about 50% more in cord blood (12.2/ micro l), and fivefold more in bone marrow (40.2/ micro l). Cord blood and bone marrow CD11c(+)/CD123(-) myeloid DC counts did not differ from each other (23.5/ micro l and 28.9/ micro l, respectively) but peripheral blood contained significantly fewer (15.5/ micro l, p = 0.006). CD11c(+)/CD123(-) DCs had significantly higher surface expression of HLA-DR (p < 0.001) in all three sources. To test for association with the DC subsets, T, B, and natural killer (NK) lymphocytes were also enumerated. In bone marrow only, significant correlations were found between the size of the CD123(+)/CD11c(-) lymphoid DC pool and NK cells (p = 0.0029) and B cells (p = 0.0033). These data support the hypothesis that a common CD123(+)/CD11c(-) DC, NK cell, and B cell progenitor is resident in marrow, and this cell may be identical to the common lymphoid progenitor previously described in mice and/or the human CD34(+)/Lin(-)/CD10(+) progenitor.     

Immunophenotype of peripheral T lymphocytes, NK cells and expression of CD69 activation marker in patients with recurrent spontaneous abortions, during the mid-luteal phase

PROBLEM: Determination of subpopulations of T lymphocytes, natural killer (NK) and activation status, in peripheral blood during the mid-luteal phase from patients with unexplained recurrent spontaneous abortion (RSA). METHOD OF STUDY: Peripheral blood samples from non-pregnant women with RSA and normal multiparous were taken and evaluated for subpopulations of T lymphocytes: CD4, CD8, ('naive-like' and 'memory-like'), TCR receptor (alphabeta and gammadelta), activation status by CD69(+surface or intracellular)/CD3(+), and NK cells (CD16(+)/CD56(dim)/CD3(-), CD16(+)/CD56 (bright)/CD3(-), CD69(+surface or intracellular)/CD56(+)/CD3(-) cells). RESULTS: The evaluation of T lymphocytes only showed an increase in the expression of CD69 (surface and intracellular) in the RSA group. Additionally, we observed an increase in the total NK cells, CD56(+) NK cells percentages, CD56(dim) NK cells and CD69 NK cells in RSA group. CONCLUSION: These observations support the concept that immunological activation of T lymphocytes and NK cells could be involved in peripheral blood during the mid-luteal phase in patients with unexplained RSA.     

Immune potentiation after fractionated exposure to very low doses of ionizing radiation and/or caloric restriction in autoimmune-prone and normal C57Bl/6 mice

Very low doses of ionizing radiation can enhance immune responsiveness and extend life span in normal mice. Total lymphoid irradiation at relatively high doses of radiation can retard autoimmune disease in genetically susceptible mice, but may impair immune function. In order to determine whether fractionated low dose exposure would enhance immune response and retard lymphadenopathy in autoimmune-prone mice, groups of C57B1/6 lpr/lpr mice were sham irradiated, exposed 5 days/week for 4 weeks to 0.04 Gy/day (0.8 Gy cumulative dose), or to 0.1 Gy/day (2.0 Gy cumulative dose). After the radiation protocol, the mice were evaluated for splenic T cell proliferative capacity, T cell subset distribution, and total spleen cell numbers. The independent and additive effect of caloric restriction was additionally assessed since this intervention has been shown to increase immune responsiveness and retard disease progression in autoimmune-prone mice. The congenic C57B1/6 +/+ immunologically normal strain was evaluated in parallel as congenic control. The results indicated that mitogen-stimulated proliferation was up-regulated in both strains of mice after exposure to 0.04 Gy/day. The proliferative capacity was additively enhanced when radiation at this dose level was combined with caloric restriction. Exposure to 0.1 Gy/day resulted in further augmentation of proliferative response in the lpr/lpr mice, but was depressive in the +/+ mice. Although the proportions of the various T cell subpopulations were altered in both strains after exposure to LDR, the specific subset alterations were different within each strain. Additional experiments were subsequently performed to assess whether the thymus is required for LDR-induced immune potentiation. Thymectomy completely abrogated the LDR effect in the +/+ mice, suggesting that thymic processing and/or trafficking is adaptively altered with LDR in this strain. In contrast, augmentation in proliferative activity after LDR in the lpr/lpr mice was maintained, although attenuated, in thymectomized mice. Taken together, these results indicate that fractionated exposure to LDR augments the proliferative response of spleen cells in both autoimmune-prone and immunologically normal mice; however, within each strain, the mechanisms appear to be different.     

CD8+ T cell activation and differentiation in allergic asthma and the impact of cytomegalovirus serological status

Allergic asthma is a chronic inflammatory T helper 2 (Th2)-associated disease. There is evidence that the atopic milieu affects the development of CD8(+) T cells in patients. We therefore analysed activation and differentiation states of CD8(+) T cells in asymptomatic patients regarding the cytomegalovirus serological status. Memory CD8(+) T cells (CCR5(high)CD3(+)CD8(+)), memory/effector cells (CD27(+)CD28(-)CD3(+)CD8(+)), effector cells (CD27(-)CD28(-)CD3(+)CD8(+)) and activated CD8(+) T cells (CD11b(+)CD3(+)CD8(+)) were identified by flow cytometry in peripheral blood of 19 (seven cytomegalovirus (CMV)(+)/12 CMV(-)) patients with allergic asthma (AA) and 21 (seven CMV(+)/14 CMV(-)) healthy controls (HC). Effector and activated CD8(+) T cells were significantly elevated in CMV(+) HC compared to CMV(-) HC. There was a non-significant trend for reduced percentages of effector CD8(+) T cells in CMV(+) AA (median: 10.4%, range: 4.4-33.8%) compared to CMV(+) HC (median: 23.1%, range: 10.7-54.1%; P = 0.128) and in CMV(-) AA (median: 4.1%, range: 0.6-13.4%) compared to CMV(-) HC (median: 5.7%, range: 0.2-17.0%; P = 0.085). Activated CD8(+) T cells were reduced significantly in CMV(+) AA (median: 17.0%, range: 6.0-29.4%) compared to CMV(+) HC (median: 40.4%, range: 18.9-67.0%; P = 0.004) and showed a non-significant trend in CMV(-) AA (median: 15.0%, range: 2.9-24.0%) compared to CMV(-) HC (median: 20.2%, range: 5.8-71.0%; P = 0.060). Activated CD8(+) T cells are significantly reduced in CMV(+) patients with allergic asthma. Furthermore, a trend for an impaired terminal CD8(+) T cell differentiation is observed in CMV(+) and CMV(-) patients with asthma.     

Distribution of lymphocyte subsets in healthy human immunodeficiency virus-negative adult Ethiopians from two geographic locales.

Immunological values for 562 factory workers from Wonji, Ethiopia, a sugar estate 114 km southeast of the capital city, Addis Ababa, Ethiopia, were compared to values for 218 subjects from Akaki, Ethiopia, a suburb of Addis Ababa, for whom partial data were previously published. The following markers were measured: lymphocytes, T cells, B cells, NK cells, CD4(+) T cells, and CD8(+) T cells. A more in depth comparison was also made between Akaki and Wonji subjects. For this purpose, various differentiation and activation marker (CD45RA, CD27, HLA-DR, and CD38) expressions on CD4(+) and CD8(+) T cells were studied in 60 male, human immunodeficiency virus-negative subjects (30 from each site). Data were also compared with Dutch blood donor control values. The results confirmed that Ethiopians have significantly decreased CD4(+) T-cell counts and highly activated immune status, independent of the geographic locale studied. They also showed that male subjects from Akaki have significantly higher CD8(+) T-cell counts, resulting in a proportional increase in each of the CD8(+) T-cell compartments studied: na?ve (CD45RA(+)CD27(+)), memory (CD45RA(-)CD27(+)), cytotoxic effector (CD45RA(+)CD27(-)), memory/effector (CD45RA(-)CD27(-)), activated (HLA-DR(+)CD38(+)), and resting (HLA-DR(-)CD38(-)). No expansion of a specific functional subset was observed. Endemic infection or higher immune activation is thus not a likely cause of the higher CD8 counts in the Akaki subjects. The data confirm and extend earlier observations and suggest that, although most lymphocyte subsets are comparable between the two geographical locales, there are also differences. Thus, care should be taken in extrapolating immunological reference values from one population group to another.     

在小鼠异基因骨髓细胞移植中超抗原SEB诱导的耐受特征

目的:研究在异基因骨髓细胞移植中葡萄球菌肠毒素B(SEB)诱导的耐受强度和细胞学特征。方法:选用C57BL/J小鼠作为受体,BALB/c小鼠作为供体。所有受体小鼠在接受6×107骨髓细胞前均接受6.0Gy60Coγ射线的照射,随机分成3组:组1为只接受6.0Gy60Coγ射线照射的对照组(照射对照组,RI);组2为照射后注射生理盐水(移植对照组,Tran.);组3为照射后注射60μgSEB(SEB组)。180d后由组2和组3实验鼠获得两组C57BL/L-BALB/c嵌合体小鼠。用流式细胞术分析移植后30~180d受体小鼠体内CD4 T、CD8 T、CD3 /NK1.1 NKT淋巴细胞亚群的数量和MHCH-2Kb、H-2Kd抗原表达的百分率,用MLR方法测定嵌合体小鼠淋巴细胞对ConA和异源性抗原的反应性。结果:(1)接受大剂量骨髓细胞移植后,注射SEB和注射生理盐水的两组小鼠均可存活180d以上,SEB组小鼠呈现出BALB/c供体小鼠的颜色特征(白色);Tran.组小鼠呈现出其灰白色。(2)SEB组嵌合体小鼠对ConA的反应性明显低于RI组和Tran.组;对异源性抗原的应答高于Tran.组。(3)SEB组小鼠外周血中CD4 T细胞的数量在移植后30~60d明显下降,随后增加;CD8 T细胞的数量不变。CD3 /NK1.1 NKT细胞的数量,从接受移植后30d开始增加,随着时间的延长而递增,到180d达到5.71%。存活180d的嵌合体小鼠,体内供体小鼠特有的MHCH-2Kd抗原的表达率高达80.95%,自体MHCH-2Kb抗原表达的百分率只占1.45%。(4)与SEB组相反,Tran.组小鼠CD8 T细胞的数量持续下降;CD3 /NK1.1 NKT细胞的数量的增加只在移植后180d上升达到5.07%。结论:在异基因骨髓细胞移植中,SEB诱导的耐受性比单纯骨髓移植诱导的耐受性强。SEB诱导的耐受性与移植早期特异性CD4 T细胞数量的减少和NKT细胞数的持续增加有关。反应性的降低表现为T细胞对ConA反应性的下降。     

Presence of restricted killer immunoglobulin-like receptor repertoire and monoclonal T-cell receptor gamma rearrangement as evidence of mixed NK/T-cell differentiation in a subset of sinonasal lymphomas

Most sinonasal lymphomas have a restricted killer immunoglobulin-like receptor (KIR) repertoire without a monoclonal T-cell receptor-gamma (TCR-gamma) rearrangement, implying an NK lineage. However, the lineage assignment of sinonasal lymphoma with a monoclonal TCR-gamma rearrangement is unclear because of its mixed NK/T phenotype. The possibility of a mixed NK/T lineage arises with the discovery of T cells with NK features, such as KIR(+) T cells or Valpha24(+) NKT cells. The former might transform into a T-cell lymphoma with both a monoclonal TCR-gamma rearrangement and a restricted KIR repertoire; the latter might give rise to a T-cell lymphoma with a monoclonal Valpha24 rearrangement and possibly a restricted KIR repertoire. To identify such mixed-lineage lymphomas, we undertook a survey of 15 consecutive sinonasal lymphomas and found six with both a restricted KIR repertoire and a monoclonal TCR-gamma rearrangement, consistent with KIR(+) T-cell lymphomas. Among these six cases, four female CD56(-)/CD44(-)/CD8(-)/CD45RO(+)/CD45RA(-) cases constituted a distinct group with a better prognosis than the rest of the male cases of sinonasal lymphomas. None of the six cases had a monoclonal Valpha24 repertoire, thus excluding a derivation from NKT cells. The predominance of KIR(+) T cells that normally function in chronic viral infections over Valpha24(+) NKT cells that typically recognize glycolipid antigens is consistent with the known association of Epstein-Barr virus infection with sinonasal lymphoma. The demonstration of mixed lineage in a mature lymphoid neoplasm is unusual and echoes the World Health Organization classification that placed NK-cell and T-cell lymphomas in a mixed group.     

Gamma interferon production by hepatic NK T cells during Escherichia coli infection is resistant to the inhibitory effects of oxidative stress

The reductive-oxidative status of tissues regulates the expression of many inflammatory genes that are induced during gram-negative bacterial infections. The cytokine gamma interferon (IFN-gamma) is a potent stimulus for host inflammatory gene expression, and oxidative stress has been shown to inhibit its production in mice challenged with Escherichia coli bacteria. The objective of the present study was to characterize the cells that produced IFN-gamma in a mouse bacterial peritonitis model and determine the effects of oxidative stress on their activation. The liver contained large numbers of IFN-gamma-expressing lymphocytes following challenge with viable E. coli bacteria. The surface phenotypes of IFN-gamma-expressing hepatic lymphocytes were those of natural killer (NK) cells (NK1.1(+) CD3(-)), conventional T cells (NK1.1(-) CD3(+)), and NK T cells (NK1.1(+) CD3(+)). Treating mice with diethyl maleate to deplete tissue thiols significantly impaired IFN-gamma production by NK cells, conventional T cells, and CD1d-restricted NK T cells in response to E. coli challenge. However, IFN-gamma expression by a subset of NK T cells, which did not bind alpha-galactosylceramide-CD1d tetramers, was resistant to the inhibitory effects of tissue oxidative stress. Stress-resistant IFN-gamma-expressing cells were also predominantly CD8(+) and bore gamma delta T-cell antigen receptors. The residual IFN-gamma response by NK T cells may explain previous reports of hepatic gene expression following gram-negative bacterial challenge in thiol-depleted mice. The finding also demonstrates that innate immune cells differ significantly in their responses to altered tissue redox status.     

Biological and methodological variation of lymphocyte subsets in blood of human adults

Although lymphocyte populations are often monitored over time, information about the biological variation over time is limited. Three-colour-flow cytometry was used to investigate the biological and methodological variation of lymphocyte populations in blood. Fifteen healthy individuals (11 females and 4 males) were longitudinally monitored for 2-8 years. Blood samples were drawn monthly when possible. In total, 493 observations were included. Absolute counts and proportions were determined for T-cells (CD3(+)), T-helper cells (CD3(+) CD4(+)), cytolytic T-cells (CD3(+) CD8(+)), B-cells (CD3(-) CD19(+)) and NK-cells (CD3(-) CD16(+)/56(+)). As to variation over the year, ANOVA testing showed only a minor monthly variation for absolute counts of the CD8(+) population (p<0.05) for October compared with June and July, whereas no significant differences were found for the other populations or in the proportions of lymphocyte subsets. Although lower than the longitudinal variation, the methodological variation, expressed as coefficient of variation (CV %), was in a similar range as the variation over time, indicating that the normal biological variation should not be overestimated, while the methodological inter-assay should be taken into consideration in longitudinal studies or monitoring of patients.     

Lymphoid organ development in rabbits: major lymphocyte subsets

Although rabbits represent an important animal model, little is known about the lymphoid organ development in this species. In the present study, lymphocyte subsets in peripheral blood, spleen, mesenteric and popliteal lymph nodes in newborn and 2-, 4-, 6- and 8-week old and adult were characterized. Lymphocyte subsets were detected using flow cytometry and monoclonal antibodies against rabbit CD4, CD8, T-cell-specific antigen and cross-reactive antibody against B-cell antigen CD79alpha. In neonates, lower numbers of T cells were detected in both peripheral blood and spleen than in mesenteric lymph nodes. In comparison with other compartments, CD79alpha(+) cells prevailed in the spleen. Post-natal development was characterized by a decreased CD4(+)/CD8(+) ratio due to increasing frequency of CD8(+) lymphocytes in all organs but mesenteric lymph nodes, where it was due to decreased numbers of CD4(+) lymphocytes. Another significant feature was the increase of B cells in peripheral blood and mesenteric lymph nodes.     

Lymphocyte subset differences in patients with chronic fatigue syndrome, multiple sclerosis and major depression

Chronic fatigue syndrome (CFS) is a heterogeneous disorder of unknown aetiology characterized by debilitating fatigue, along with other symptoms, for at least 6 months. Many studies demonstrate probable involvement of the central and autonomic nervous system, as well as a state of generalized immune activation and selective immune dysfunction in patients with CFS. The aim of this study was to compare the lymphocyte subsets of patients with chronic fatigue syndrome to those of patients with major depression and multiple sclerosis as well as those of healthy control subjects. No differences were found in total numbers of T cells, B cells or natural killer (NK) cells. However, differences were found in T, B and NK cell subsets. Patients with major depression had significantly fewer resting T (CD3(+)/CD25(-)) cells than the other groups. Patients with major depression also had significantly more CD20(+)/CD5(+) B cells, a subset associated with the production of autoantibodies. Compared to patients with multiple sclerosis, patients with CFS had greater numbers of CD16(+)/CD3(-) NK cells. Further study will be required to determine whether these alterations in lymphocyte subsets are directly involved in the pathophysiology of these disorders, or are secondary effects of the causal agent(s).     

HIV-1 Nef protein expression in human CD34+ progenitors impairs the differentiation of an early T/NK cell precursor

HIV-1 impairs the production of T cells, through mechanisms that are still unknown. Here, we investigated the effect of the expression of HIV-1 Nef on the T-cell potential of human hematopoietic CD34(+) precursors. Those progenitors were transduced by using lentiviral vectors expressing Nef and cultured on OP9-DL1 cells allowing the differentiation of T cell from human hematopoietic precursors. We demonstrate that Nef impairs the generation of a CD3epsilon(+)CD5(+) CD1a(+) precursor stage that has initiated a D-J rearrangement of the TCRbeta locus. Onward stages of T-cell development were also affected with a quantitative reduction of CD4(+) intraCD3epsilon(+) Immature single positive cells (ISP), Double Positive (DP) CD4(+)CD8(+) TCRalphabeta T cells and CD56(+) NK cells. But B cell production was not affected. Limiting dilution analyses demonstrated a significant reduction in the frequency of T/NK progenitors among Nef-expressing CD34(+) cells. Altogether, these data demonstrate that Nef interferes with the differentiation of a primitive lymphoid human precursor with a T/NK potential.     

Expansion of monocyte-like cells expressing natural killer cell-associated antigens in response to low-dose total lymphoid irradiation

We have previously shown that total lymphoid irradiation conditioning of baboons before renal transplantation is a potent immunosuppressive strategy, resulting in quiescent T cell function and increased NK cell activity. This paper shows that proportion of cells expressing NK- associated antigens, which expand during and after total lymphoid irradiation, includes large, granular cells expressing surface antigens associated with monocytes. NK cells and monocytes from peripheral blood were detected and quantified using an array of fluorescent-labelled monoclonal antibodies and flow cytometry. During and after exposure to total lymphoid irradiation there was an increase in the frequency of large, granular CD11b(+) and CD16(+), CD56(+), CD16(+) CD38(+) cells and absolute numbers of CD14(+)CD11b(+) and CD14(+) CD16(+) mononuclear cells. This suggested that expansion of a unique population of CD14(+) monocytes, co-expressing CD16 and CD11b antigens, normally found on NK cells. Consequently, the significant increase in CD14(+) CD16(+) cells demonstrates that CD16(+) cells do not solely define NK cells in the mononuclear cell fraction isolated during and after this form of radioconditioning.     

CD41+/CD45+ cells without acetylcholinesterase activity are immature and a major megakaryocytic population in murine bone marrow

Murine megakaryocytes (MKs) are defined by CD41/CD61 expression and acetylcholinesterase (AChE) activity; however, their stages of differentiation in bone marrow (BM) have not been fully elucidated. In murine lineage-negative (Lin(-))/CD45(+) BM cells, we found CD41(+) MKs without AChE activity (AChE(-)) except for CD41(++) MKs with AChE activity (AChE(+)), in which CD61 expression was similar to their CD41 level. Lin(-)/CD41(+)/CD45(+)/AChE(-) MKs could differentiate into AChE(+), with an accompanying increase in CD41/CD61 during in vitro culture. Both proplatelet formation (PPF) and platelet (PLT) production for Lin(-)/CD41(+)/CD45(+)/AChE(-) MKs were observed later than for Lin(-)/CD41(++)/CD45(+)/AChE(+) MKs, whereas MK progenitors were scarcely detected in both subpopulations. GeneChip and semiquantitative polymerase chain reaction analyses revealed that the Lin(-)/CD41(+)/CD45(+)/AChE(-) MKs are assigned at the stage between the progenitor and PPF preparation phases in respect to the many MK/PLT-specific gene expressions, including beta1-tubulin. In normal mice, the number of Lin(-)/CD41(+)/CD45(+)/AChE(-) MKs was 100 times higher than that of AChE(+) MKs in BM. When MK destruction and consequent thrombocytopenia were caused by an antitumor agent, mitomycin-C, Lin(-)/CD41(+)/CD45(+)/AChE(-) MKs led to an increase in AChE(+) MKs and subsequent PLT recovery with interleukin-11 administration. It was concluded that MKs in murine BM at least in part consist of immature Lin(-)/CD41(+)/CD45(+)/AChE(-) MKs and more differentiated Lin(-)/CD41(++)/CD45(+)/AChE(+) MKs. Immature Lin(-)/CD41(+)/CD45(+)/AChE(-) MKs are a major MK population compared with AChE(+) MKs in BM and play an important role in rapid PLT recovery in vivo.     

Identification and characterization of lymphoid precursors in the murine intestinal epithelium.

Although in vivo evidence supports a role for the murine intestinal epithelium in the extrathymic generation of certain intraepithelial T lymphocytes (IEL), no intraepithelial cells with in vitro lymphoid progenitor potential have yet been demonstrated. Using reaggregate fetal thymic organ culture techniques, we show that a subset of CD3(-) cells isolated from the intestinal epithelium of young mice is capable of generating T cells (alpha beta and gamma delta) and NK1.1(+) cells in vitro. A novel IEL subset bearing a low level of CD45 was identified and found to comprise cells expressing highly immature lymphoid markers including CD34, c-kit, CD122, CD127 and high levels of CD16 and CD44. This subset represents 20-30% of intraepithelial CD45(+) cells from 4-week-old wild-type and nude mouse strains and contains cells with in vitro T cell differentiation capacity. The identification of such an early pluripotent precursor phenotype within the intestinal epithelium implies that the potential for T cell generation exists at this site, and suggests that extrathymic T cell generation may occur within the epithelium itself.     

两次随访的康复期SARS患者T细胞亚群及其相关活化分子的研究

目的 :探讨康复期SARS患者外周血T细胞亚群及其相关活化分子的变化。方法 ::对出院后的SARS患者 ,采用统一调查问卷及实验室检测进行随访研究。两次随访中 ,应用流式细胞仪检测了我院 70余例经中西医结合治疗的康复期SARS患者外周血中CD3 、CD4 、CD8 、CD8 CD2 8 、CD8 CD2 8-、CD3 CD2 5 、CD3 CD6 9 、CD3 HLA DR T细胞的百分率及CD4 /CD8 T细胞的比率的改变 ,并以描述性分析及t检验进行比较分析。结果 :两次随访中 ,CD3 、CD4 和CD8 CD2 8 T细胞的百分率 (均值 )及CD4 /CD8 T细胞的比率 ,均明显低于正常值 (P <0 .0 5 ) ,而CD8 CD2 8-T细胞的百分率则显著增高 (P <0 .0 1)。第 2次随访中 ,检测的CD3 、CD8 、CD3 CD2 5 、CD3 CD6 9 及CD3 HLA DR T细胞的百分率 (均值 ) ,及CD4 /CD8 T细胞的比率 ,与第 1次的相比较差异较显著 (P <0 .0 1) ,其余项目差异均不明显。结论 :随着康复期的延长 ,患者的免疫功能逐渐恢复 ,病毒对T细胞活化的影响逐渐减少。     

The interaction of the Wnt and Notch pathways modulates natural killer versus T cell differentiation

The Wnt and Notch signaling pathways have been independently shown to play a critical role in regulating hematopoietic cell fate decisions. We previously reported that induction of Notch signaling in human CD34(+)CD38(-) cord blood cells by culture with the Notch ligand Delta 1 resulted in more cells with T or natural killer (NK) lymphoid precursor phenotype. Here, we show that addition of Wnt3a to Delta 1 further increased the percentage of CD34(-)CD7(+) and CD34(-)CD7(+)cyCD3(+) cells with increased expression of CD3 epsilon and preT alpha. In contrast, culture with Wnt3a alone did not increase generation of CD34(-)CD7(+) precursors or expression of CD3 epsilon or preT alpha gene. Furthermore, Wnt3a increased the amount of activated Notch1, suggesting that Wnt modulates Notch signaling by affecting Notch protein levels. In contrast, addition of a Wnt signaling inhibitor to Delta 1 increased the percentage of CD56(+) NK cells. Overall, these results demonstrate that regulation of Notch signaling by the Wnt pathway plays a critical role in differentiation of precursors along the early T or NK differentiation pathways. Disclosure of potential conflicts of interest is found at the end of this article.