MAB19101 Sigma-AldrichAnti-Tenascin Antibody, clone DB7

The use of biopolymers in peribulbar injection for controlled drug delivery provides alternative options to eyedrops and intravitreal or surgical methods. Polymerizable biopolymers are especially likely to have a role because of their particular properties. In liquid form, they can be easily injected into the target site and, after polymerization, they provide a prolonged and controlled release of the drug. This study was undertaken to demonstrate the suitability of a thermopolymerizable biopolymer poloxamer (Lutrol F127) for peribulbar injections and controlled drug release.

Cryosections of epithelial, sarcomatoid, and biphasic malignant mesotheliomas (EMM, n = 11; SMM, n = 5; BMM, n = 6) of the pleura were immunostained with monoclonal antibodies to integrin subunits alpha 1-6 and v, and beta 1-4. Localization patterns were compared with those known to occur in pulmonary and other adenocarcinomas (PADC, ADC). EMM and the epithelial component of BMM (ecBMM) expressed alpha 1,3,5,6, and v and beta 1 and 4. SMM and the sarcomatoid elements of BMM (scBMM) reacted variably for alpha 1,3,5,6 and v, and beta1. Reactions for alpha3, found in all tumors, were strongest in EMM, ecBMM, and PADC. Our findings indicate that EMM and ecBMM parallel PADC and most ADC in their expression of alpha6 beta4, underscoring that this laminin integrin receptor is intimately associated with these neoplastic epithelial phenotypes. Also, our observations on alpha3 beta1 suggest that this cell-cell adhesion-mediating integrin is related to the epithelial phenotype. Notably, all malignant mesotheliomas (MM), including those with distinct glandular structures, expressed the alpha5 beta1 fibronectin receptor, thus paralleling most sarcomas and differing from PADC and most other ADC. We conclude that irrespective of architectural and cytologic variants, transformed mesothelial cells possess an integrin repertory that differs significantly from that of most ADC, including those of the lung. These findings set mesothelium apart from epithelia and may prove helpful as adjunct tools for the differential diagnosis between EMM and AD.

In this investigation, tenascin (Tn) expression was studied in 51 cases of different types of fibrotic lung disorders originating for years 1981 to 1995. Our aim was to test if accumulation of Tn at the site of lung injury in usual interstitial pneumonia (UIP) could correlate with the prognosis. Lung biopsies taken from 28 patients with UIP, six with desquamative interstitial pneumonia (DIP), six with sarcoidosis, five with extrinsic allergic bronchioloalveolitis, five with bronchiolitis obliterans organizing pneumonia (BOOP), and one with nonspecific interstitial pneumonia were studied for the expression of Tn by using an immunohistochemical technique. In addition to Tn immunohistochemistry, selected cases were also studied by immunoelectron microscopy and Western blotting. For prognostic studies in UIP the clinical follow-up information was obtained from the patient records. The expression of Tn was increased in each type of fibrosis, especially in UIP. In immunoelectron microscopy the most prominent labeling in UIP was found in association with collagen fibers and within the type 2 pneumocytes. Every studied case of UIP showed reactivity for a polypeptide of M(r) approximately equal to 200,000 by Western blotting. In patients with UIP, increased Tn expression, especially under metaplastic bronchiolar-type epithelium, was associated with a shortened survival time. Immunoelectron microscopic findings support the idea that Tn in UIP is synthesized by the regenerating epithelial rather than interstitial cells in response to pulmonary interstitial inflammation.

Tenascin (Tn) is an extracellular matrix glycoprotein transiently expressed in epithelial-mesenchymal interaction areas during embryogenesis. Tn is expressed in a limited manner in adult tissues but emerges during wound healing and tumorigenesis. We have studied Tn expression by immunohistochemistry in 137 small node-negative breast cancers treated with breast-conserving surgery and post-operative radiotherapy during 1985-1989. None of the patients had undergone any adjuvant hormonal therapy or chemotherapy. Stromal Tn expression itself could not predict distant metastasis. However, Tn staining in the area of the invasion border seemed to be a strong predictor of distant metastasis, with an estimated 5-year metastasis-free survival (MFS) of 85% in Tn-positive cases compared to 98% in Tn-negative ones. The prognostic impact of Tn in the invasion border on MFS was stronger than that of tumour size and grade. This staining appears to be a useful adjunct for the estimation of breast-cancer metastasis.

An enzyme immunoassay was developed for quantification of tenascin in biologic samples. An enzyme conjugate prepared by coupling peroxidase to a well-characterized, affinity-purified monoclonal antibody EB2 to human tenascin was used as principal reagent. The assay comprises 96-well microtitration strip plates with immobilized monoclonal antibody DB7 to human tenascin. By using a novel monoclonal antibody suppressing human-anti-mouse-factor, MAK33, in the sample buffer, the specificity of the test could be improved. The method has a minimum detectable sensitivity of 1.5 ng tenascin and permits determination of tenascin in various biologic samples. The coefficients of variation within run and between run ranged from 0.9% to 5.0%. The average tenascin concentration in normal plasma was 0.97 mg/L (n = 200) and in serum 0.73 mg/L (n = 200). The tenascin concentrations were also determined in samples of urine, bile, amniotic fluid, seminal fluid, cerebrospinal fluid, bronchoalveolar lavage (BAL) fluid, and pleural fluid showing general applicability of the assay. The method permits the determination of tenascin in samples of different body fluids from various diseases, including cancer, showing increased amounts of the protein at the tissue level.

The expression of tenascin was assessed immunohistochemically. In normal oral mucosa, immunoreactivity for tenascin was seen either as a delicate line underlining the epithelium or in the stromal papillae. In oral lichen planus, a marked enhancement of tenascin immunoreactivity in the lamina propria was associated with focal infiltrates of inflammatory cells and seemed to reflect the intensity of inflammation. In lichenoid reactions in which only a sparse inflammatory infiltrate was present a band-like tenascin reactivity was seen. Oral psoriform reactions and chronic hyperplastic candidosis showed a prominent tenascin reaction in the connective tissue papillae among infiltrates of inflammatory cells. The results show that tenascin content is increased in oral mucocutaneous diseases and related lesions and that the abundance of tenascin reflects the intensity of the inflammatory reaction.

AIMS: To determine the distribution of tenascin in normal and pathological bone marrow. METHODS: 48 different bone marrow lesions were studied immunohistochemically using a monoclonal antibody to tenascin. RESULTS: Tenascin immunoreactivity was found in lesions with increased fibrosis and high numbers of reticular fibres. The strongest immunoreactivity was found in myelofibrosis. Bone marrow from acute and chronic myeloid and lymphatic leukaemias showed weak or moderate immunoreactivity. In hyperplasias inconsistent reticular tenascin immunoreactivity was found; in normal bone marrow, only a few scattered positive fibres were occasionally seen. CONCLUSIONS: Tenascin was generally observed in conditions in which megakaryocytic hyperplasia was a feature. This is in line with the notion that tenascin synthesis in bone marrow fibroblasts is stimulated by TGF-beta which is synthesised by the megakaryocytic lineage. Tenascin also contains EGF-like repeats. It might therefore function as a growth promoter and in this way could also stimulate synthesis of other matrix components. On the other hand, tenascin could function as an adhesive molecule to some cells of the bone marrow. The presence of tenascin in many pathological states of the bone marrow suggests that it may have a role in their pathogenesis and that it also could be a potential marker of disease.

The distribution of tenascin immunoreactivity was analyzed in nonneoplastic lung tissue, benign lung tumors, and different types of lung carcinomas. In nonneoplastic lung tissue, tenascin could be observed in the basement membranes of the bronchial epithelium and endothelial cells, smooth muscle cells, and bronchial cartilage. Strong tenascin immunoreactivity was seen in the stroma of all the carcinomas of various histologic types. The staining intensity was stronger in the stroma of squamous cell carcinomas than in the stroma of the other types of lung carcinomas. In 10 of 27 squamous cell carcinomas, a granular intracytoplasmic reactivity could also be observed in a subpopulation of tumor cells. Similar intracytoplasmic reactivity was observed in 2 of 27 adenocarcinomas and in both adenosquamous carcinomas. In other types of lung tumors, individual cells did not have intracytoplasmic tenascin, except for one case of leiomyoma, which showed a weak, linear, intracytoplasmic tenascin reactivity. In lung hamartomas, tenascin could be seen in the cartilaginous component of the tumor and in the areas of basement membranes of the bronchial epithelium. In the carcinoid tumors, the stroma displayed a faint positivity for tenascin. These results show that tenascin is widely expressed in the stroma of lung carcinomas. A proportion of lung carcinomas also expressed intracytoplasmic tenascin immunoreactivity, suggesting that tumor cells may be able to synthesize tenascin. In the lung, tenascin positivity is not, however, restricted to malignant neoplasms, as evidenced by the presence of tenascin in nonneoplastic lung parenchyma and in some benign lung tumors.

We studied by immunohistochemistry the distribution of tenascin with the monoclonal antibody 100EB2, and compared it with that of laminin in breast tissue samples from fetal, adult resting, lactating, and aging parenchyma, variants of fibrocystic disease, fibroadenomas, cystosarcoma phylloides, and ductal and lobular carcinomas. Monoclonal antibodies were applied to cryosections by the avidin-biotin-complex method; selected samples were studied by double immunofluorescence, and by Western blot analysis. In adult resting and aging breasts, tenascin immunoreactivity was noted in the periductal and periacinar stromal regions as thin irregular bands; in the lactating breast, broader periductal bands were observed. In these samples, laminin immunoreactivity was a single continuous line around ducts, acini, and vessels. In fetal breasts, tenascin appeared as thick periductal bands, whereas laminin remained as a delicate single line. In FCD, tenascin increased around ducts showing hyperplasia, papillomas and apocrine metaplasia, whereas laminin retained its delicate linear pattern. Similar patterns were seen in fibroadenomas and cystosarcoma phylloides with variable tenascin reactivity in the stroma beyond the ducts. Tenascin immunoreactivity was markedly increased around ducts containing in situ carcinoma appearing as broad bands, whereas that of laminin showed a linear, frequently discontinuous appearance. Prominent stromal tenascin immunoreactivity was seen in infiltrating ductal and lobular carcinomas, whereas laminin was virtually absent save for scattered lines. The abundance of tenascin in the carcinomatous stroma contrasted with its scarcity in the non-neoplastic stromal regions. By Western blotting, both chains of tenascin with molecular weights 250,000 and 180,000 were shown in ductal and lobular carcinomas as well as in normal breast. Tenascin immunoreactivity was noted in the periepithelial stromal regions of adult resting and aging breast ducts and acini. The amount of tenascin was moderately enhanced in certain physiologic conditions (fetal growth, gestation), as well as hyperplasias, dysplasias (fibrocystic disease) and benign tumors, whereas it was markedly enhanced in intraductal and infiltrating carcinomas. During fetal mammary development, adult physiologic and pathologic hyperplasias, and in carcinomas, the increasing tenascin reactivity contrasted with the stable or decreasing laminin reactivity.

Tenascin, a novel extracellular matrix protein, was demonstrated immunohistochemically in rabbit corneas that had healed after anterior keratectomy. Tenascin-like immunofluorescence (T-LI) appeared in the corneal stroma at the wound area only. The wound edge showed the most intense specific fluorescence. The corneal epithelium, in general, displayed a moderate T-LI. Wounding did not induce any change in epithelial T-LI or T-LI located in the stroma outside the wound.