Conventional tumour markers such as CEA and alpha-fetoprotein are used to monitor treatment and detect recurrence'`of malignancy. These tumour markers also show a non-specific reactivity in benign diseases' and sometimes in even normal individuals.6À ttempts have been made to search for monoclonal antibodies which might be used as tumour markers. CA 19-9, an antigenic determinant defined by murine monoclonal antibody 1116NS19-9, was generated by somatic hybridisation of the mouse myeloma cell line and splenocytes from a mouse

Interleukin 5 (IL-5) is a glycosylated polypeptide that acts as a key factor for B-cell growth and differentiation. We demonstrated previously that there are two classes (high and low affinity) of IL-5 receptors on murine chronic B-cell leukemic cells (BCL,. Treatment of surface-bound radiolabeled IL-5 with bivalent crosslinkers identified a polypeptide of Mr 92,500. In this study, we analyzed characteristics of high-affinity IL-5 receptors on IL-5-dependent early B-cell lines (T-88 and T88-M), mouse myeloma cells The T-cell-replacing factor (TRF) was defined as a B-cell differentiation factor (1-5) and was considered to be important in the T-cell/B-cell interaction for B-cell triggering (6, 7). TRF produced by a murine T-cell hybridoma (B151K12) stimulates activated B cells or neoplastic B-cell lines, such as chronic B-cell leukemia (BCL1), to differentiate into immunoglobulin-secreting cells (3,8), to promote their DNA synthesis (B-cell growth factor II activity) (9), and to induce increased expression of interleukin 2 (IL-2) receptors (10-12). Murine TRF has been purified to homogeneity and a monoclonal antibody to TRF has been developed (13). With the cloning and expression of the genes encoding murine and human TRF, it has been demonstrated conclusively that multiple activities of B151-TRF are mediated by a single molecule (14-16). Based on diverse activities of TRF in various target cells, TRF or B-cell growth factor II is now called interleukin 5 (IL-5) (14).Because IL-5 has an important role in the growth and differentiation of not only B cells but also T cells and eosinophils (17)(18)(19), the nature of receptor for IL-5 on the cell surface is of great interest. The availability of a purified recombinant IL-S has made it possible to search for a specific receptor for IL-5. To initially characterize the membrane IL-5 receptors, we used BCL1-B20 cells, a murine chronic B-cell leukemic cell line, that differentiates into IgMsecreting cells in response to IL-5. Using radiolabeled murine IL-5, we demonstrated that BCL1-B20 cells bear two types of IL-5 receptors with high (Kd = 66 pM) and low (Kd = 12 nM) affinities for . We also reported that cell-bound IL-5 is associated with a membrane protein of Mr 46,500. It is not clear, however, whether the high-affinity binding sites consist only of a Mr 46,500 protein.In this report, we will describe that under conditions favoring the interaction of IL-5 with the high-affinity receptor, two major 35S-labeled IL-5 crosslinked protein bands of Mr 92,500 and Mr 160,000 are detected not only on lipopolysaccharide (LPS)-stimulated BCL1-B20 cells but also on proliferating IL-5-dependent cell lines that have sufficient numbers of high-affinity receptor for IL-5. Characterization of the IL-5 receptor, both at the functional and structural levels, should give us insight into the diverse biological activities of IL-5 on various target cells. MATERUILS AND METHODS CellLines. An IL-5-responsive BCL1-B20 line was isolated as described (20) by limiting dilution culture of ...

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This study concerns the definition of carcinoma of the gastric cardia. The topography of the esophagogastric mucosal junction (mucosal EGJ) was investigated with an endoscope in 182 patients who were free of hiatal hernias, ulcers, and neoplasms in the esophagus and stomach. The relationship between the EGJ and the cardiac gland area was then examined histologically in 56 resected specimens containing intact EGJs and cardia gland areas. Furthermore the cancerous center was determined; the shortest distance between the cancerous center and the EGJ and the amount of esophageal invasion were measured in 102 resected carcinomas located close to the junction; the carcinomas contained the EGJ and were good enough for pathohistological examination. The EGJ was located 0.5 - 1.0 cm proximal to the His angle (the gastric cardia) in radiological and endoscopic examinations. Histologically the cardiac gland area was found to straddle the EGJ at a range of about 1 cm proximal and 2 cm distal to the junction. Among the upper stomach carcinomas, most of the tumors (87.5%) whose center was located within 2 cm from the EGJ invaded the esophagus. In conclusion, carcinoma of the gastric cardia is defined as a lesion with its center located within 1 cm proximal and 2 cm distal to the EGJ.

T cell-replacing factor (TRF)/IL-5 is a glycosylated polypeptide that acts as a key factor for B cell growth and differentiation. Since IL-5 action is probably mediated by specific cell surface receptor(s), we have characterized the binding of IL-5 to cells using biosynthetically [35S]methionine-labeled IL-5 and 125I-IL-5 that had been prepared using Bolton-Hunter reagent. The radiolabeled IL-5 binds specifically to BCL1-B20 (in vitro line) (a murine chronic B cell leukemic cell line previously shown to differentiate into IgM-secreting cells in response to IL-5) within 10 min at 37 degrees C. There are two classes of binding sites with high affinity (Kd = 66 pM) and low affinity (Kd = 12 nM) for IL-5 and an average number of binding sites for high affinity and for low affinity were 400 and 7,500 per cell, respectively. The specificity of binding of radiolabeled IL-5 has been confirmed by demonstrating that only unlabeled IL-5 and anti-IL-5 mAb but not by IL-1, IL-2, IL-3, IFN-gamma, and GM-CSF inhibit radiolabeled IL-5 binding to BCL1-B20 cells. Treatment of surface-bound radiolabeled IL-5 with bivalent crosslinkers identified a membrane polypeptide of Mr 46,500 to which IL-5 is crosslinked. A variety of cell types have been surveyed for the capacity to bind specifically radiolabeled IL-5 with high affinity. BCL1 cells MOPC104E (murine myeloma cell line) expressed IL-5-R, whereas BAL. 17 and L10 A (B cell lymphoma) did not. T cell line, mastocytoma cell line, or macrophage tumor cell line did not display detectable levels of IL-5-R. were hardly detectable on normal resting B cells but were expressed on LPS-activated B cells, fitting the function of IL-5 that acts on activated B cells for their differentiation into Ig-secreting cells. Intriguingly, early B cell lines (J-87 and T-88) that grow in the presence of IL-5 expressed significant but low numbers of high-affinity binding sites for IL-5. The biological effects of IL-5 were mediated by high-affinity binding sites. The identification and characterization of IL-5-R should provide new insight into the apparent diverse biological activities of IL-5.