Showing papers on "Receptor expression published in 1981"

Expression of epidermal and nerve growth factor receptors and soft agar growth factor production by human lung cancer cells.

Abstract: Seventeen well-characterized human lung cancer cell lines were examined for the presence of specific membrane receptors for epidermal growth factor (EGF) and nerve growth factor (NGF) as well as for the production of diffusible factors capable of stimulating soft agar growth. These cell lines represented all four major histological types of human lung cancer including small cell carcinoma of the lung (SCCL) and the three types of non-SCCL (epidermoid, large cell, and adenocarcinoma). The SCCL lines included three lines referred to as “converters” because they had lost SCCL morphological and biochemical properties during prolonged passage in vitro . Specific receptors for EGF and NGF were detected by measuring the binding of 125I-radiolabeled growth factor to the cell surface. These assays revealed that EGF receptors are found on five of six non-SCCL cell lines and are not found on any of the SCCL lines. In contrast, NGF binding was detected at low levels on three of eight SCCL lines and on all three SCCL converters but was not observed for non-SCCL lines. Thus, SCCL and SCCL converter cell lines are distinguished from non-SCCL by the pattern of membrane receptors for EGF and NGF. Such differences may ultimately prove useful as biological markers for the different histological types of lung cancer. Moreover, the majority of SCCL cells and all of the non-SCCL cells tested were found to produce diffusible growth factors which can stimulate soft agar growth of nontransformed normal rat kidney fibroblasts. Although some correlation between soft agar growth factor production and the absence of EGF receptors may exist for SCCL cells, the production of transforming growth factors appears to be a general property of human lung cancer cells in vitro and is independent of EGF receptor expression.

Detection of estrogen receptor in breast and endometrial carcinoma by the immunoperoxidase technique

Abstract: Paraffin-embedded tissues from 15 women with breast or endometrial carcinomas were analyzed in a study designed to explore the possible value and validity of an immunoperoxidase method for the detection of estrogen receptor in formalin-fixed paraffin-embedded tissue. Results were compared with biochemical assays for estrogen receptor performed on cytosols of fresh tissue from the same patients. There was complete correlation in nine of 15 (60%) of the tumors analyzed. Four cases (26.7%) were judged positive for estrogen binding sites by immunoperoxidase but were negative for estrogen receptor by biochemical assays; in two cases the converse was observed. The immunohistologic technique is relatively rapid and utilizes fixed paraffin sections of the same tissue that is used for standard histologic diagnosis. The provision of a permanent record that can be kept for future reference provides an advantage over immunofluorescence methods that have been advanced for the detection of estrogen receptors. The excellent morphology achieved permits an assessment of the staining of individual cells in relation to the usual histologic criteria employed in the diagnosis of breast and endometrial cancer. This stands in contrast to biochemical cytosol-based assays that take no account of variations in receptor expression by the tumor cells or variations in the proportion of the assayed material that is in fact neoplastic as distinct from supporting stroma and connective tissue.

The effect of complement in adherent immune complexes on Fc and C3 receptor expression in human monocytes.

Abstract: The effect of complement in surface-bound immune complexes on the expression of Fc and C3 receptors in membranes of adherent human monocytes was examined. Monocytes were isolated from mononuclear leucocyte preparations by adherence to substrates containing fibrin, fibrin with immune complexes (containing rabbit IgG antibodies), or fibrin with immune complexes and mouse complement. Fc or C3 receptors on the top or exposed surface of the monocytes were detected by rosette formation with sheep erythrocytes coated with IgG (EA) or IgM and complement (EAC). Monocytes adherent to surface-bound immune complexes exhibited an absence of EA rosette-forming ability without any change in EAC rosettes. This specific loss of Fc receptor function was induced more easily in freshly-isolated monocytes than in cells maintained in suspension culture for up to 7 days. The presence of complement in the immune complex substrates did not reverse the decrease in Fc receptors seen with freshly-isolated or cultured monocytes. Monocytes adherent to immune complexes and complement exhibited a decrease in C3 receptor function. This decrease was more readily induced in cells cultured for three days in the presence of serum than in freshly-isolated monocytes. Experiments performed with EAC or immune complex substrates relatively enriched in C3b or C3bi indicated that C3b in the substrate induced a decrease in monocyte C3b receptors and C3bi led to a decrease in C3bi receptors. No evidence was found for C3d receptors on the human monocytes although these receptors on a subpopulation of human lymphocytes appeared to be altered in a similar fashion.

Human macrophage function in cancer. Systemic and local changes detected by an assay for Fe receptor expression

Abstract: The activity of human peripheral blood monocytes and pulmonary alveolar macrophages was examined with a rosette assay that detects changes in Fc receptor expression. Compared with peripheral blood monocytes from normal subjects, the peripheral blood monocytes of patients with carcinoma of the lung were found to be activated in this respect. In contrast, compared with pulmonary alveolar macrophages from normal subjects, carcinomas exhibited depressed function in terms of receptor alveolar macrophages from lungs bearing primary expression. Trypsinization of macrophages to remove bound immunoglobulin indicated that this depression of receptor activity was not due to blocking of receptors by immunoglobulin or immune complexes. In an in vitro study the expression of Fc receptors by cultured macrophages was shown to be depressed by a heat-stable, low-molecular-weight material in supernatants of cultured carcinoma tissue from the lung, breast, and urinary bladder.

Seven murine cell lines with properties of macrophages.

Abstract: : Seven phagocytic murine cell lines established from cultures of thymic lymphomas closely resembled authentic mouse peritoneal macrophages in their morphology and phagocytic properties. They secreted lysozyme and contained large quantities of nonspecific esterase, beta-glucuronidase, acid phosphatase, and lysozyme. They lacked the surface antigens of thymic lymphocytes (Thy-1,2 antigen) or bursa-equivalent lymphocytes (immunoglobulin), but they expressed receptors for immunoglobulin and complement. Complement-mediated rosettes did not occur in the absence of divalent cations. Efficient phagocytosis of sheep erythrocytes required opsonization with rabbit IgG antibodies. Ia8 antigen was recent on all four H2D cell lines. Two of the cell lines can be readily cloned; we used these to demonstrate that variation in receptor expression and morphology was not due to the presence of multiple cell types. None of the cell lines was tumorigenic in nude mice or normal syngeneic mice. These macrophage-like cell lines provide well-characterized models which can be used to examine certain aspects of macrophage function under defined conditions without lymphoid cell admixture. (Author)

Expression of receptors for IgA in hairy-cell and other B-cell leukaemias.

Abstract: In six cases of both hairy-cell leukaemia (HCL) and chronic lymphocytic leukaemia (CLL) it was shown that the pathological cells express receptors for the Fc portion of IgA (RFc alpha). Many of the cells simultaneously expressed receptors for IgA, IgM and IgG, and blocking studies showed that these are distinct receptors. In contrast, the malignant cell of most of the various other B-cell leukaemias studied showed low levels of RFc alpha expression. The significance of the results is briefly discussed and it is suggested that receptor expression may be a marker of certain stages of B-cell development.