Tissue-specific expression of the tight junction proteins claudins and occludin in the rat salivary glands

Tight junctions (TJs) are essential features of endothelial barrier membranes and of fluid-secreting epithelial cells, such as in the salivary glands. Novel integral membrane proteins have been identified as components of TJs, namely claudins and occludin. The aim of the present study was to determine the distribution of occludin and claudins in the large salivary glands of the rat. The parotid, submandibular and sublingual salivary glands were harvested from adult Sprague-Dawley rats and cryostat sections were stained using immunoperoxidase and immunofluorescence methods. Claudin-1 was expressed in endothelial cells of microvessels and in short selected segments of the duct system. Claudin-3 was expressed principally in the acinar cells and intercalated ducts, while claudin-4 was principally expressed by the striated and interlobular ducts. Claudin-5 was specific to endothelial cells of microvessels. Occludin was ubiquitously detected in the duct system. Double labelling and confocal microscopy showed some co-localization of claudin-3 with claudin-4, and minimal co-localization of occludin with claudin-4, in the striated ducts. Claudin 2 was not detected in any of the salivary glands. The results indicate specificity of the chemical composition of tight junctions in the rat salivary glands, and may reflect different physiological roles for TJs in the glandular and duct epithelial cells, and in endothelial cells of salivary gland microvessels.     

Mutations of thyrotropin receptor gene

 Thyrotropin is the primary pituitary hor- mone which stimulates the growth and differentiation of thyroid cells. TSH binds a specific receptor present in the plasma membrane of thyroid cells and signals the G protein transducers, which activate different effec- tors, mainly adenyl cyclase and phospholipase C. The TSH receptor belongs to a broad class of receptors known as seven-loop receptors because they contain a long stretch of amino acids which cross the plasma membrane seven times. Mutations in the TSH receptor gene have been found in hyperfunctioning thyroid adenomas. These mutations are: (a) somatic (present only in the tumor), (b) dominant (only one copy of the gene is affected), and (c) lead to the constitutive activation of the cAMP signaling cascade. Most mutations which have been identified occur in the intracellular loop III and in the transmembrane domain VI. Germline mutations in the same regions of the receptor have been found in congenital nonautoimmune hyperthyroidism. In addition, germ line mutations have been described in the extracellular domain of the receptor leading to increased TSH levels. The clinical implications of these findings are discussed. Received: 15 January 1996 / Accepted: 8 March 1996     

Immunolocalization of extracellular matrix proteins and integrins in sarcoid lymph nodes

 To improve our understanding of the role of extracellular matrix (ECM) proteins and integrins during the processes of granuloma formation in sarcoidosis, we examined the distribution of ECM proteins and the expression of integrins in sarcoid lymph nodes by immunohistochemical methods. We also examined the expression of transforming growth factor-β1 (TGF-β1), which is one of major regulators for synthesis of ECM proteins. Most ECM proteins were detected in the periphery of the granulomas in a concentric pattern, and fibronectin was diffusely detected from an early to a regressive stage. Compared with normal lymph nodes, most β1-integrin subfamilies (α1, α4, α5 and α6) were more strongly expressed on lymphocytes around the granulomas. Epithelioid cells exhibited strong expression of the α5 molecule. Fibroblasts exhibited the expression of the α2 and α5 molecules surrounding ECM proteins. The α5β1 molecule had a distribution similar to that of fibronectin. TGF-β1 was detected in epithelioid cells throughout the various evolutional stages and its expression was especially marked in mature granulomas. Interaction of fibronectin and the α5β1 molecule may have an important role in the process of formation of sarcoid granuloma. The expression of TGF-β1 may be involved in the regression of sarcoid granuloma by initiating fibrosis and atrophy of epithelioid cells. Received: 2 December 1997 / Accepted: 19 February 1998     

Vaccination against meningococcus in complement-deficient individuals

Autoantibodies to CRP were reported previously in patients suffering from toxic oil syndrome. This syndrome resembles autoimmune diseases such as systemic lupus erythematosus (SLE) or systemic scleroderma. We therefore examined the prevalence of antibodies to CRP and other acute-phase proteins in autoimmune diseases, including SLE, subacute cutaneous lupus erythematosus (SCLE), systemic scleroderma (SSc), and primary biliary cirrhosis (PBC), as well as in bone marrow transplantation-induced chronic graft-versus-host disease and eosinophilia–myalgia syndrome. IgG antibodies to CRP were found in 78% of SLE and in 30% of SCLE patients, while 16% of patients with PBC were positive. In up to 45% of patients with SSc predominantly IgG antibodies to ceruloplasmin were detectable. Lack of systemic involvement as in discoid lupus erythematosus and localized scleroderma (morphea) correlated with low or absent antibody formation. However, no correlation was found between anti-acute-phase protein antibodies with liver disease or other organ involvement. Adsorption studies revealed that non-native epitopes on the CRP molecule, termed modified CRP, are the main target of antibodies. Chronic inflammatory tissue injury in systemic autoimmune disease might increase the presentation of cryptic epitopes of CRP to the threshold required for T cell activation.     

Monoclonal antibodies to human secretory "pregnancy-associated endometrial alpha 1-globulin," an insulin-like growth factor binding protein: characterization and use in radioimmunoassay, Western blots, and immunohistochemistry

Monoclonal antibodies were raised against pregnancy-associated endometrial alpha 1-globulin (alpha 1-PEG), a 32 KD insulin-like growth factor binding protein (IGF-BP), which represents a major secretory product of the human decidualized endometrium during pregnancy. This class of IGF-BP has been implicated in the modulation of action, inhibitory and stimulatory, of insulin-like growth factors. Immunization with the protein purified from pregnancy endometrium resulted after myeloma fusion in the isolation of six hybridoma clones and the antibodies produced were characterized. The Ka of the antibodies ranged between 4.75 x 10(9) M-1 and 0.7 x 10(8) M-1. In Western blots all monoclonal antibodies reacted with purified protein of molecular weight 32 KD and specifically detected this IGF-BP species in culture medium and cytosolic extracts of pregnancy endometrium and amniotic fluid. The monoclonal antibodies appear to define three epitope-bearing regions as evidenced by their reactivity to polypeptide fragments of the protein. After synthesis and secretion by tissue explants in vitro the protein is susceptible to cleavage into fragments possessing different monoclonal antibody-defined reactivity. Employing immunohistochemical techniques the protein was principally localized to decidual cells in tissue sections of pregnancy endometrium and solely to these cells after enzymic digestion of the tissue. The implications of these results are discussed with respect to potential role of IGF-BP in the action of IGF upon the IGF-1 receptor-bearing populations, including lymphocytes and trophoblast cells, D in the decidua.     

Influenza A virus-induced apoptosis is a multifactorial process: exploiting reverse genetics to elucidate the role of influenza A virus proteins in virus-induced apoptosis

Three influenza viruses, A/Puerto Rico/8/34-A/England/939/69 clone 7a (H3N2), A/Fiji/15899/83 (H1N1), and A/Victoria/3/75 (H3N2), induce different levels of apoptosis in vitro at equal moi; Clone 7a > A/Victoria > A/Fiji. Previous studies have shown that several viral proteins from clone 7a and A/Fiji, including PB2, NA, NS1, M1, and M2, induce apoptosis when expressed individually fused to the herpes simplex virus tegument protein, VP22. However, this did not reflect viral protein-protein-RNA interactions known to occur within infected cells. To explore the role of viral proteins in apoptosis under infection conditions, recombinant viruses with single or triple gene exchanges were generated using A/Victoria or clone 7a as the background virus. Inserting the A/Fiji NS or PB2 gene into A/Victoria or clone 7a significantly reduced the level of apoptosis compared to the parent virus while clone 7a PA or NP genes increased apoptosis. Inserting A/Fiji NA or HA or clone 7a NS, M, NA, or HA genes individually into A/Victoria had no significant effect on apoptosis. Surprisingly, inserting the M, NA, and HA genes of A/Fiji together into clone 7a reduced apoptosis, whereas inserting clone 7a M, NA, and HA together into A/Fiji increased apoptosis. These results suggest that no single virus protein induces apoptosis and that the combination of genes required may be strain specific, highlighting the difficulty of predicting the virulence of new strains that arise in nature. No support for the view that apoptosis is essential for high virus yields was obtained as high virus yields were obtained with viruses that induced both high and low levels of apoptosis.     

蛋白转导域介导BCR/ABL抗原对CML患者T细胞的活化作用

目的：研究蛋白转导域(PTD)介导的BCR／ABL抗原对慢性髓细胞白血病(CML)患者T细胞的特异性活化作用。方法：利用基因工程技术，将PTD基因与CML b3a2 bcr／abl基因融合并原核表达。将纯化的PTD—BCR／ABL融合蛋白与CML患者外周血单个核细胞(PBMC)体外共孵育，用流式细胞仪分别检测CD4^ 、CD8^ T细胞上活化抗原CD25的表达。结果：终浓度为100mg／L的PTD—BCR／ABL抗原体外刺激4d后，10例CML患者中，5例表现为CD8^ T细胞活化，2例表现为CD4^ T细胞活化，其中有1例CD8^ 和CD4^ T细胞同时活化；而作为对照的BCR／ABL抗原刺激组无一例表现为CD8^ 或CD4^ T细胞活化。结论：PTD能将外源性BCR／ABL抗原转导入抗原呈递细胞内，加工呈递后激活抗原特异性CD8^ 及CD4^ T细胞，为CML特异性CD8^ 、CD4^ T细胞的体外活化及细胞免疫治疗开辟一条新的途径。     

c-erbB-2、VEGF和组织蛋白酶D在胃癌中的表达及其相关性

目的：探讨癌基因c-erbB-2、血管内皮生长因子（VEGF）和组织蛋白酶D（Cath-D)在胃癌中的表达及其与胃癌生物学行为的关系。方法：采用免疫组织化学（S－P）法，检测了102例胃癌手术标本中c-erbB-2、VEGF及Cath-D的表达，同时观察了网状纤维分布与c-erbB-2、Cath-D之间的关系，并将检测结果与跟踪随访资料进行了综合分析。结果：102例胃癌组织中c-erbB-2表达阳性率为38.24%（39／102），与胃癌浸润深度（P＜0.05）、淋巴结转移（P＜0.05）密切相关；VEGF表达阳性率为50％（51／102），与胃癌浸润深度（P＜0.01）、生长方式（P＜0.01）、淋巴结转移（P＜0.01）密切相关；Cath-D表达阳性率为81.37%(83/102)，与胃癌浸润深度（P＜0.05）、生长方式（P＜0.05）、淋巴结转移（P＜0.05）及脉管内有无癌栓（P＜0.05）有关。对生存期分析显示：Cath-D、VEGF、c-erbB-2阳性患者预后差，5年生存率低于阴性表达患者。结论：c-erbB-2、VEGF及Cath-D与胃癌的生长、浸润、转移、预后有密切关系，可作为判断胃癌生物学行为和预后的重要指标。