Characterization of NK cells and extrathymic T cells generated in the liver of irradiated mice with a liver shield

We previously reported that c-kit⁺ stem cells which give rise to extrathymic T cells are present in the liver of adult mice. Further characterization of extrathymic T cells in the liver of adult mice is conducted here. When mice with a liver shield were lethally (9.5 Gy) irradiated, all mice survived. All tested organs showed a distribution pattern of hepatic lymphocytes on day 7. The distribution pattern in the liver was characterized by an abundance of NK (CD3^? IL-2Rβ⁺) and extrathymic T cells (CD3^int IL-2Rβ⁺) before and after irradiation. To determine their function, post-irradiation allogeneic bone marrow transplantation (BMT) was performed in mice with or without a liver shield. Allogeneic BM cells were rejected in mice with a liver shield and specific activation of CD8⁺ CD3^int IL-2Rβ⁺ cells was induced. At that time, potent cytotoxicity of liver mononuclear cells (MNC) against allogeneic thymocytes was induced. Both NK1.1⁺ and NK1.1^? subsets of CD3^int cells expanded in these mice. An in vivo elimination experiment of the subsets indicated that the NK1.1⁺ subset of CD3^int cells (i.e. NK T cells) was much more associated with the rejection of allogeneic BM cells. However, even after the elimination of NK T cells, allogeneic BM cells were rejected. In this case, granulocytes expanded in parallel with NK1.1^? subsets. Granulocytes may also be associated with the rejection of allogeneic BM cells. These results suggest that the liver is an important haematopoietic organ even in adult life.     

一株铜绿假单胞菌中检出两种新的整合子

目的研究铜绿假单胞菌多重耐药的临床分离株RJ217中发现的两个新整合子的结构，并分析其在多重耐药性中的作用。方法用改良三相试验分析RJ217产β-内酰胺酶的情况，用常规和长片段PCR法扩增耐药基因和整合子，并对PCR产物进行序列分析。结果发现铜绿假单胞菌RJ217携带两个新的整合子，其中一个携带veb-I型超广谱β-内酰胺酶(ESBL)基因，这两个整合子的结构分别为IS10-like-veb-I-aadB-oxa10／aadA1和aadB-oxa10／aadA1。结论整合子介导的耐药基因在RJ217的多重耐药性中发挥了重要的作用。     

Activation of hepatic NKT cells and subsequent liver injury following administration of alpha-galactosylceramide

It has been established that alpha-galactosylceramide (alpha-GalCer), a glycolipid, is recognized by natural killer T (NKT) cells together with the monomorphic MHC-like antigen, CD1d, in mice and humans. In this study, we examined how NKT cells are modulated by in vivo administration of alpha-GalCer in mice. When 2 microg (or more)/mouse of alpha(-GalCer was injected i.p., the majority of NKT cells disappeared in the liver and spleen, possibly undergoing apoptosis, on day 1. At this time, NKT cytotoxicity seen in liver lymphocytes also disappeared. In parallel with this numerical and functional change of NKT cells, there was always concomitant hepatocyte damage, as shown by histology and elevated levels of transaminases. Subsequently, the number and function of NKT cells continued to increase from day 3 to day 7. The response seen in hepatic (and splenic) NKT cells did not occur in thymic NKT cells. All these phenomena induced in the liver did not appear in NKT-deficient mice such as beta2-microglobulin(-/-) and CD1d(-/-) mice. These results shed further light on the in vivo interaction between NKT cells and alpha-GalCer in mice.     

细胞松弛素B对内皮细胞损伤修复的影响

目的观察细胞松弛素B对内皮细胞损伤修复过程中微丝骨架系统的形态结构变化,研究阻断微丝功能对内皮细胞损伤修复的影响。方法以培养单层内皮细胞损伤模型,采用免疫荧光染色和3H-TdR掺入法,研究微丝功能对创面愈合及细胞增殖的影响。结果内皮细胞在损伤修复过程中伴随微丝特殊而有序的变化。用细胞松弛素B破坏微丝,可不同程度抑制创面的愈合及细胞增殖,并呈一定的时间-剂量依赖关系。结论微丝功能在促进内皮细胞修复过程中起重要作用,可通过直接或间接效应影响DNA合成,从而影响修复过程。     

CCK-8上调小鼠腹腔巨噬细胞B7.1和B7.2表达并增强其协同刺激活性

目的： 探讨八肽胆囊收缩素（CCK-8）对静息巨噬细胞B7.1和B7.2表达及其协同刺激功能的影响。方法：用CCK-8（10-12-10-6 mol/L）孵育小鼠腹腔巨噬细胞一定时间，采用流式细胞术分析细胞表面B7.1和B7.2含量的变化。用免疫磁珠从小鼠脾细胞分离CD4+T细胞，按4∶〖KG-*2〗1数量比与腹腔巨噬细胞（预先用CCK-8和/或抗B7.1抗体、抗B7.2抗体、CCK1R拮抗剂CR1409、CCK2R拮抗剂CR2945孵育24 h）共同体外培养，同时加入ConA 5 mg/L，采用［3H］掺入法测定CD4+T细胞增殖反映巨噬细胞的协同刺激活性。结果：CCK-8可上调静息巨噬细胞B7.1及B7.2的表达，并增强巨噬细胞的协同刺激活性。CCK-8的作用呈剂量依赖性，最大效应剂量是在10-9-10-7 mol/L之间。抗B7.2抗体可减轻CCK-8增强巨噬细胞协同刺激活性的作用，CR1409及CR2945均能逆转CCK-8的上述作用，且CR1409的作用较CR2945更明显。结论：CCK-8通过上调巨噬细胞B7.2表达而增强其协同刺激活性，该作用由CCK1R及CCK2R介导，其中CCK1R起主要介导作用。     

Increase in the proportion of granulated CD56+ T cells in patients with malignancy.

Evidence is presented for the existence of a unique T cell population which expressed one of the natural killer (NK) markers, CD56 antigen, in humans. Although such CD56+ T cells were a minor population in the peripheral blood (< 10%), they were abundant in the liver (up to 50%), which was recently demonstrated to be a major organ for extrathymic T cell differentiation in mice. As in the case of extrathymic T cells in mice, these CD56+ T cells in humans contained a higher proportion of gamma delta T cells than did CD56- T cells, contained double-negative CD4-8- cells, and had the morphology of large granular lymphocytes. This unique population of CD56+ T cells tended to be elevated in the blood and among tumour-infiltrating lymphocytes in patients with colorectal cancer, especially in advanced cases. These results raise the possibility that, as in mice, CD56+ T cells with extrathymic T cell properties may also be associated with tumour immunity in humans.     

先天性软骨发育不全成纤维细胞生长因子受体3基因1138位核苷酸点突变的检测

目的 验证成纤维细胞生长因子受体3(fibroblast growth factor receptor 3，FGFR3)跨膜区1138位核苷酸为先天性软骨发育不全突变热点及用变性梯度电泳方法筛查的效果。方法 对17例临床诊断为先天性软骨发育不全患者进行基因组DNA聚合酶链反应－限制性酶切片段长度多态性（polymerase chain reaction-restriction fragment length polymorphism,PCR-RFLP)分析，并用变性梯度凝胶电泳（denaturing gradient gel electrophoresis,DGGE)进行其它突变位点的筛查。结果 17例患者中14例RFLP检测显示能被Sfc I酶切，提示存在1138位核苷酸G→A的转换，且均为杂合子。17例用Msp I酶切均阴性，提示无G→C的颠换。DGGE方法的筛查中，酶切阳性的14例标本均显示存在杂合型突变。3例PCR－RFLP检测阴性的标本未显示突变位点，提示在该扩增区域确实不存在突变位点。结论 FGFR3跨膜区1138核苷酸G→A的突变是软骨发育不全的主要发病机理，DGGE可作为筛查某一区域基因突变的敏感而可靠的检测手段，尤其是对杂合子的检测。     

Identification and characterization of temperature-sensitive mild mutations in three Japanese patients with nonsevere forms of very-long-chain acyl-CoA dehydrogenase deficiency

Very-long-chain acyl-CoA dehydrogenase (VLCAD) deficiency is clinically classified into severe, intermediate, and myopathic forms. We identified mutations in three unrelated Japanese patients with VLCAD deficiency: two with the myopathic form and one with the intermediate form, all compound heterozygotes of K264E/M437V, A416T/1798delA, and P89S/IVS16-3delAA, respectively. We characterized four missense mutations, K264E, M437V, A416T, and P89S, by transisent expression analysis, using SV40-transformed fibroblasts derived from a VLCAD-null patient, as recipient cells. In transient expression of the wild-type VLCAD cDNA, VLCAD activity at 30 degrees C was higher than at 37 degrees C. Moreover, this temperature-sensitive character is more evident in all the mutant proteins tested than in wild type. Based on characterization of the five missense mutations identified in four Japanese patients, including data on one patient with the myopathic form previously reported, patients with the nonsevere forms (intermediate or myopathic forms) have missense mutations with residual activities in at least one allele. Expression analysis at 30 degrees C may be more useful for evaluating these missense mutations, compared with that at 37 degrees C.     

Existence of a small population of IL-2Rβhi TCRint cells in SCG and MRL-lpr/lpr mice which produce normal Fas mRNA and Fas molecules from the lpr gene

Mice carrying the lpr gene, SCG and MRL-lpr/lpr mice, were used to characterize the phenotype and lpr gene of abnormally proliferating T cells in these mice. A major population which expanded in these mice were T cells expressing intermediate (int) levels of T cell receptor (TCR) (and CD3) and the phenotype of interleukin-2 receptor (IL-2R)β^lo α^? (possibly abnormal TCR^int cells). The levels of TCR^hi cells of thymic origin (generated through the mainstream of T cell differentiation in the thymus) profoundly decreased after the onset of disease. However, a small population of normal TCR^int cells (i.e. IL-2Rβ^hi α^?) were also found to exist in all tested organs. For example, the majority of abnormal IL-2Rβ^lo TCR^int cells were CD4^?8^? CD2^?, while normal IL-2Rβ^hi TCR^int cells were a mixture of single-positive cells (mainly CD8⁺), CD4^?8^? cells and CD2⁺ cells. Moreover, normal TCR^int cells preferentially produced normal Fas mRNA and Fas molecules from the lpr gene. This phenomenon explains the leaky appearance of normal Fas mRNA and Fas molecules in mice carrying the lpr gene. It is suggested that a small population of IL-2Rβ^hiTCR^int cells are resistant to the lpr genetic abnormality.