Search

Monoclonal antibody (MCA) 44-3A6 detects a cell-surface transmembrane phosphoprotein frequently expressed by pulmonary adenocarcinoma (AC) and associated with glandular differentiation. This antibody has been found to have utility in assessing routine formalin fixed paraffin-embedded pulmonary neoplasms, as well as the cytopathological evaluation of sputum and bronchial brushings. Recently, it has been shown to be useful in cytological diagnosis of pleural effusions. This study is directed at evaluating its effectiveness in detecting immunoreactive neoplastic cells in body fluids (BF) arising in other tissues. A retrospective cohort of 57 cases was studied, consisting of 36 pleural, 19 ascitic, and 2 pericardial BF. After evaluation of Papanicolaou-stained slides, the BF specimens were immunostained with MCA 44-3A6 using the avidin-biotin-peroxidase complex (ABC) method. In 29 cases, tissue sections of the primary tumors, were also available for immunostaining with MCA 44-3A6. Results showed that 39/42 (93%) of AC BF cases were positive and 28/42 (66%) stained intensely (3-4+) with 75-100% of the AC cells staining in each case. All of the 18 benign and non-AC malignant BF were negative. The staining patterns in the tissue sections of the 29 cases that had corresponding BF samples were similar. We conclude from this study that the MCA 44-3A6 (1) is useful in detecting cells consistent with AC in BF; (2) does not stain inflammatory cells or reactive mesothelial cells, thus helping distinguish reactive from malignant BF; and (3) frequency and pattern of expression in BF parallels its expression in tissue specimens. This study confirms that this MCA is a useful adjunct tool in the cytopathological evaluation of BF.

Double-stranded RNA (dsRNA)-dependent protein kinase (p68) has been shown to be induced by alpha-interferon (IFN-alpha) in mammalian cells. It binds to dsRNA, and is believed to be a factor in the control of both cellular and viral protein synthesis. This report describes the use of a new monoclonal antibody (MAb) TJ4C4, to monitor levels of p68 in a patient with AIDS-associated Kaposi's sarcoma. Using a novel immunoperoxidase/iron staining method, we examined formalin-fixed, paraffin-embedded biopsies prior to, and 4 months after the initiation of IFN therapy. Immunostaining showed low levels (1+ staining) of p68 in the pretreatment tissue, whereas a marked increase (4+ staining) was noted during interferon treatment. This staining suggests an increased level of intracellular p68 expression. This patient has subsequently remained on IFN-alpha therapy and is alive with no evidence of Kaposi's sarcoma, 6 1/2 years after diagnosis. The use of MAb TJ4C4 will greatly facilitate the study of p68 kinase in clinical tissues, and may provide a way to monitor the effects of IFN therapy.

In this report we describe the expression of the adenocarcinoma associated antigen recognized by the monoclonal antibody 44-3A6, in various tissues during normal human fetal development. Conventional, formalin-fixed and paraffin-embedded sections of normal organs were examined from fetuses ranging from 9 to 42 weeks of gestation. Immunohistochemical localization of antigen-antibody complexes was accomplished using the avidin-biotin complex (ABC) method using horseradish peroxidase. The monoclonal antibody (MAb) 44-3A6 detects a cell surface 40 kD protein which is frequently expressed by adenocarcinomas and by select normal glandular tissues. Detectable expression of this protein was seen at different time periods during fetal development depending on the tissue. This expression was confined to a relatively small range of cell types and tissues; immunostaining was noted in select epithelial cells of the aerodigestive tract, exocrine pancreas, neural tissues, renal tubules, and transitional urothelium, as well as in other tissues. This immunostaining generally, but not invariably, corresponded with patterns previously reported in benign and/or malignant neoplasms of adult tissues. In most instances, once expression occurred within a tissue, it continued through gestation. These data show that this tumor associated gene product is differentially expressed in a broad range of normal developing human fetal tissues.

In this report we describe the expression of the ras proto-oncogene p21 protein in various tissues during normal fetal development. Conventional, formalin fixed and paraffin-embedded sections of normal organs were examined from fetuses ranging 9 to 42 weeks of gestation. Immunohistochemical localization of ras p21 was accomplished using the broadly reactive, mouse monoclonal antibodies RAP-5 and Y13-259. The monoclonal antibody DWP, which is specific for a mutated form of ras p21 having a valine/cysteine at amino acid position 12, was also used. Detectable expression of the p21 protein was seen at different time periods during fetal development depending on the tissue. The expression of ras p21 (as detected by RAP-5 and Y13-259) was noted in a wide range of cell types and tissues; intense immunostaining was noted in epithelial cells of the gastrointestinal tract, exocrine and endocrine pancreas, renal tubules and transitional urotheliem, as well as in other tissues. This immunostaining generally, but not invariably, corresponded with patterns previously reported in benign and/or malignant neoplasms of adult tissues. In most instances ras p21 expression, when present, occurred during periods of rapid growth in given organ systems. However, some actively proliferating fetal tissues such as thymus and spleen, failed to express detectable ras p21 suggesting that factors other than cell cycle may influence its expression. No reactivity with DWP was noted in any of the tissues, suggesting that the mutated forms detected by this monoclonal antibody are not expressed during normal human embryogenesis. These data show that there is regulated expression, and broad distribution of this gene product in normal developing human fetal tissue.

A monoclonal antibody, 44-3A6, was raised against the human pulmonary adenocarcinoma cell line A549. This antibody recognizes a protein antigen at the cell surface, which is preserved after formalin fixation and paraffin embedding. Immunohistochemical staining of lung tissue with this antibody revealed diffuse immunoreactivity of type II pneumocytes. Bronchial epithelial cells were also focally immunoreactive. Immunostaining of various bronchopulmonary carcinomas demonstrated characteristic patterns of reactivity. All of the 42 adenocarcinomas and 18 carcinoids were strongly immunoreactive either diffusely or focally. The immunoreaction occurred at the cell membrane and/or in the cytoplasm. None of the 39 squamous cell carcinomas, 12 bronchioloalveolar carcinomas, and 30 small cell neuroendocrine carcinomas was immunostained. Ten intermediate cell neuroendocrine carcinomas and 8 well-differentiated neuroendocrine carcinomas were relatively weakly immunoreactive, while 7 and 2 of them were negative. Six adenosquamous carcinomas were focally positive in glandular and "basaloid" areas, whereas squamous areas were negative. Twenty-one large cell carcinomas were focally immunoreactive, while 6 were negative. It appears that MCA 44-3A6 is an effective marker for certain features of "glandular" differentiation, which may be present even in tumors lacking obvious glands, and that it may be useful for the differential diagnosis of various bronchopulmonary carcinomas.

The IgG1 monoclonal antibody, 44-3A6, was raised against the human lung adenocarcinoma cell line, A549. It has been shown to react with a 40,000 MW protein found on the cell surface, which is preserved in formalin-fixed paraffin-embedded tissues. A recent study of pulmonary carcinomas utilizing immunohistochemical methods showed exclusive binding to lung adenocarcinomas, subsets of neuroendocrine tumors, some carcinoids and a subset of large cell carcinomas. Reactivity was not seen in squamous cell carcinomas and small cell neuroendocrine carcinomas. In addition, melanomas, sarcomas and hematologic malignancies do not express this antigen. We now report on the reactivity pattern of 44-3A6 in adenocarcinomas of nonpulmonary primary sites and in normal adults organs. Strong diffuse staining of neoplastic cells in adenocarcinomas of the stomach, colon, pancreas, gallbladder and breast was noted. Adenocarcinomas arising in the endometrium, ovary, kidney, prostate, thyroid and liver were either negative or showed weak and/or focal reactivity. Strong staining patterns were even noted in adenocarcinomas which had an 'undifferentiated' component; i.e., lacking well-defined glandular elements. Immunoreactivity was noted in epithelial cells in several tissues from which these adenocarcinomas arose including the bronchial tract, stomach, small intestine, pancreas and colon, whereas epithelial cells from the endometrium, kidney, ovary, prostate and thyroid were negative or showed diffuse weak immunoreactivity. Our finding indicate that monoclonal antibody 44-3A6 recognizes an epithelial antigen on subsets of normal as well as transformed glandular epithelia. The differential pattern of expression of its target antigen probably reflects differences in tumor genesis and/or differentiation.

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.

This article describes a case of pleomorphic adenocarcinoma of the pancreas, metastatic to the adrenal glands and liver, that has unique cytological and histological features. Cytology demonstrated numerous mononuclear and multinucleated tumor giant cells as well as numerous osteoclast-like giant cells. These features were also seen in the histological sections, as were numerous clear cells. Electron microscopy demonstrated features suggesting an epithelial origin of the epulis cells. Prominent immunoreactivity with the monoclonal antibody (MCA) 44-3A6 of these cellular constituents was seen in the aspirate and in the tissue sections. These data provide further evidence to support the epithelial origin of these cellular components.