Radioimmunoimaging of human small cell lung carcinoma with I-131 tumor specific monoclonal antibody.

In this study, an IgM monoclonal antibody (MAb600D11) directed against human small cell lung cancer (NCI-H69) was radiolabeled with iodine-131, and the biodistribution and image quality of the radiolabeled antibody was evaluated. Radiolabeling was achieved in a solid-phase system consisting of 1,3,4,6-tetrachloro-3a,6a-diphenylglycoluril. Labeling efficiencies and protein purification were accomplished using gel exclusion chromatography while radioimmunoreactivity was determined using a solid-phase radioimmunoassay procedure. The biodistribution of I-131-labeled MAbs was determined in Sprague-Dawley rats up to 7 days after injection. Highest organ concentrations were observed in liver (3.91 +/- 0.47 (SD) and 0.17 +/- 0.04 (SD) mean percent injected dose at 1-7 days after injections) and in thyroid (5.33 +/- 0.71 (SD) and 5.32 +/- 2.01 (SD) mean percent injected dose at 1-7 days after injection). Nude mice, bearing either a small cell lung tumor (NCI-H69) or a nonspecific tumor (adenocarcinoma), were injected with 400-800 microCi of I-131 labeled monoclonal antibody. Optimum tumor visualization was observed 2-4 days after injection with tumor concentrations as high as 10.4% of the initial injected dose. The results demonstrated that radioimmunoimaging of human small cell lung carcinoma was feasible with the tumor-specific IgM I-131-labeled MAb.

Microsomal metabolism of the carcinogen, N-2-fluorenylacetamide, by the mammary gland and liver of female rats. I. Ring- and N-hydroxylations of N-2-fluorenylacetamide.

We determined ring- and N-hydroxylations of a systemic mammary gland carcinogen, N-2-fluorenylacetamide (2-FAA), by microsomal fractions of liver and mammary gland of female rats and the effects of in vivo and/or in vitro modifiers of these oxidations. Pretreatment of lactating rats with 3-methylcholanthrene (3-MC) or beta-naphthoflavone (beta-NF) and non-lactating (50-day old virgin) rats with beta-NF showed similar effects in that the formation of 3-, 5-, 7-, 9- and N-hydroxy-2-FAA by hepatic microsomes was increased manyfold and the formation of 1-hydroxy-2-FAA was induced. In mammary gland microsomes, the formation of 3-, 5- and 7-hydroxy-2-FAA was likewise increased, but of 9-hydroxy-2-FAA was unaffected. Only mammary microsomes of lactating rats had capacity for N-hydroxylation which was increased approximately 3 times by pretreatment of rats with 3-MC or beta-NF. All of the induced increases of metabolites of 2-FAA in hepatic and mammary microsomes were inhibited by 0.1 mM alpha-naphthoflavone (alpha-NF) in vitro. Pretreatment of non-lactating rats with phenobarbital increased only the formation of 7-hydroxy-2-FAA in hepatic microsomes which was further stimulated by alpha-NF in vitro. The latter also stimulated the formation of 7- and 9- hydroxy-2-FAA by hepatic microsomes of the uninduced rats, but had no effects in mammary microsomes, in which 9-hydroxy-2-FAA was a major metabolite. Hence, the data showed qualitative and quantitative differences between lactating and non-lactating rats in metabolism of 2-FAA by mammary microsomes which may result from differences in the levels (e.g., of cytochrome P-450) and activities of microsomal enzymes determined herein. In hepatic microsomes of these rats, differences in quantities of metabolites of 2-FAA (3-, 7-, 9- and N-hydroxy-2-FAA) were found in corn oil-treated rats only. The solvent (methanol or acetone) used for addition of 2-FAA to the incubation mixtures altered quantitatively the metabolite profiles in hepatic and mammary microsomes of 3-MC or beta-NF treated rats. The formations of 1- and 3- or 5- and 7-hydroxy-2-FAA were greater in the presence of acetone or methanol, respectively. The results of this study suggest that the formation of phenolic and N-hydroxy metabolites of 2-FAA in both hepatic and mammary microsomes of lactating rats is catalyzed by similar form(s) of cytochrome P-450 induced by pretreatment with 3-MC or beta-NF.(ABSTRACT TRUNCATED AT 400 WORDS)

Immunohistochemical localization of the immunodominant differentiation antigen lacto-N-fucopentaose III in normal adult and fetal tissues.

Monoclonal antibodies were produced by immunizing rats with human small cell lung carcinoma (SCLC) cell lines. Monoclonal antibodies 600D11 and 624A12 were found to be directed against the ceramide pentasaccharide that contains the lacto-N-fucopentaose III (LNFP III) sequence of sugars, an isomer of the Lewis A blood group antigen. LNFP III is an immunodominant antigen whose reactivity is maintained in formalin-fixed paraffin-embedded sections (PS). LNFP III has been recognized in a number of human tumors including: SCLC; adenocarcinomas of the breast, gastrointestinal tract, genitourinary tract, and lung; renal cell carcinoma; neuroblastoma; and myelogenous leukemia. We now report the normal adult and fetal tissue distribution of the LNFP III antigen by immunoperoxidase staining on PS utilizing 600D11 and 624A12. Binding was demonstrated in bronchial epithelium and bronchial glands; squamous epithelium of the esophagus; gastric crypts, duodenal enterocytes and Brunners glands; argentaffin cells; jejunal and colonic goblet cells; pancreatic acinar cells; salivary glands; endocervical and exocervical cells; skin epidermis; myelinated motor fibers; cells of the adrenal medulla and anterior pituitary gland; polymorphonuclear leukocytes (PMNs); tissue macrophages and renal proximal tubules and loops of Henle. Staining was localized to cell membranes and within the cytoplasm, with greatest intensity at the apical and basal portions of the cells. These staining patterns were noted in adult and neonatal tissues, and initial expression could be traced to approximately the second trimester of fetal development. Knowledge of the normal tissue distribution of this immunodominant antigenic determinant may offer insight into its structural and functional role in benign and malignant tissues.