Immunohistochemical localization of placental alkaline phosphatase, carcinoembryonic antigen, and cancer antigen 125 in normal and neoplastic human lung.

Human placental alkaline phosphatase (HPLAP), carcinoembryonic antigen (CEA), and cancer antigen 125 (CA 125) were localized immunohistochemically in paraffin sections of normal lung tissue from 16 patients, using monoclonal antibodies and an indirect avidin-biotin-peroxidase staining procedure. HPLAP and CEA were present in epithelial cells of respiratory bronchioli and alveolar type I pneumocytes. CEA was also observed in the tracheal, bronchial, and bronchiolar epithelium. CA 125 was present in the tracheal, bronchial, bronchiolar, and terminal bronchiolar epithelium; in the tracheal and bronchial glands; and in the pleural mesothelium. Normal and hyperplastic type II pneumocytes were negative for HPLAP, CEA, and CA 125 but were histochemically positive for nonspecific alkaline phosphatase. Fetal lung tissue between 11 and 15 weeks of gestation was negative for HPLAP, CEA, and CA 125. The fetal tracheal and bronchial epithelium, tracheal glands, and pleural mesothelium were positive for CA 125. For ten malignant pulmonary tumors investigated, HPLAP staining was observed in five, CEA in nine, and CA 125 in seven. The localization of HPLAP, CEA, and CA 125 in apparently normal constituents of all pulmonary specimens is in disagreement with the concept that the expression of these substances in the lung is indicative of abnormal cellular activity.

Cyclosporine nephrotoxicity: comparative cytochemical study of rat kidney and human allograft biopsies.

The aim of this study was to detect early renal changes in the rat. Female Wistar rats received oral doses of cyclosporine (12.5, 25 or 50 mg/kg daily). The duration of the experiment was 1, 2, and 3 weeks. Controls received the vehicle only (olive oil). The following alterations were seen by light microscopy: Hypertrophy of the juxtaglomerular apparatus (PAS stain). Cytoplasmic droplets of neutral fat (Oil Red 0) in clusters of cortical tubules, probably belonging to the same nephron. Both the above phenomena increased with dosage and duration of treatment and were absent in controls. In the fat containing tubulus (FCT) brush border staining (alkaline phosphatase) was decreased or absent. Since after PAS the brush border was visualized in many FCT, it is concluded that many FCT were proximal tubulus (PT) of which the brush border has been damaged. In FCT mitochondrial staining (Cytochrome oxidase activity) was strongly decreased or absent. Mean lysosomal volume (acid phosphatase and dipeptidase II) is increased in the PT; in some cyclosporine animals, lysosomes were enlarged, while in others they were comparable to controls. Electron microscopy showed in some PT cells an increased number of empty vacuoles and focal alteration of mitochondria. Normal mitochondria were present next to grossly altered mitochondria. Autophagocytosis of mitochondria was clearly present. The lysosomes appeared swollen and contained electron dense material, not organised in the typical 50 A pattern of myeloid figures. These morphological changes suggest a defect of mitochondrial metabolism, leading to lipid deposition in PT. The mitochondrial metabolism can be disturbed by a direct toxic effect of cyclosporine or indirectly via ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Enzyme immunoassay of human placental and germ-cell alkaline phosphatase in serum.

Placental alkaline phosphatase (placental ALP, PLAP) and germ-cell ALP (GCAP, also known as placental-like ALP), expressed in gonadal cancer tissues, are potential tumor markers. Four monoclonal antibodies, raised against PLAP and recognizing different epitopes, were selected to study the influence of the following variables on the accuracy of PLAP and GCAP measurement: phenotype, molecular form, and glycation pattern of PLAP and GCAP; incubation temperature; and interferences by serum during immunobinding. Nine GCAP phenotypes were identified, interacting with each antibody at a lower affinity than was seen for the more common PLAP phenotypes. Antibody affinity is higher for the free hydrophilic dimeric forms of PLAP and GCAP, and is not influenced by the degree of glycation. In serum or tissue extracts, measurement of PLAP or GCAP is most nearly accurate when immunoincubations are performed at 37 degrees C, with use of antibodies 327 and 7E8, respectively. In addition, correct measurements are achieved only when, during immunobinding, serum is incubated with an equal volume of deoxycholate (9 g/L final concentration).

Tumor markers in the human ovary and its neoplasms. A comparative immunohistochemical study.

The incidence and histologic characteristics of the expression of placental alkaline phosphatase (PLAP) in ovarian tumors was compared with that of five other tumor antigens. Three monoclonal antibodies were used for the specific localization of PLAP. PLAP was present in some sex cord cells of the 13-16-week fetal ovary, probably germ cells. In normal ovaries, all antigens except carcinoembryonic antigen (CEA) were frequently found in inclusion cysts; the germinal epithelium was positive only for cancer antigen 125 (CA 125). The frequency and extent of PLAP expression in nonmucinous carcinomas was higher than observed for CA 19-9 and CEA, but was lower than for CA 125 and human milk fat globule antigen. Serous tumors had the highest PLAP expression, followed by endometrioid and poorly differentiated adenocarcinomas, and some other tumors. PLAP was predominantly membranous; its histologic distribution was in general heterogeneous. Different antibodies to PLAP gave different staining intensities in some tumors, but the staining patterns were always qualitatively identical.

Magnetic beads in suspension enable a rapid and sensitive immunodetection of human placental alkaline phosphatase.

The kinetics and efficiency of the interaction between placental alkaline phosphatase and a monoclonal antibody (laboratory number 327) were determined by immunoassay using microtitre plates or magnetic beads. While only up to 45% of placental alkaline phosphatase was bound to microwells precoated with this antibody, even after prolonged incubation, no less than 60% and 100% binding were reached using magnetic beads after 1 and 3 h incubations, respectively. High-molecular-mass placental alkaline phosphatase and complexed placental alkaline phosphatase forms were also completely bound to magnetic beads in the presence of deoxycholate (up to 9 g/l for serum samples). The assay sensitivity was improved up to 4-fold. In addition, 100% binding of the antigen was achieved during simultaneous incubation of magnetic beads, monoclonal antibody (125 micrograms/l), and placental alkaline phosphatase. This one-step enzymatic assay, based on magnetic beads, is an attractive alternative to the classic assay performed in microtitre plates, enabling rapid, precise, and sensitive antigen detection, and only necessitating a minimum of laboratory equipment.

Segment-specific localization of intestinal-type alkaline phosphatase in human kidney.

Specific monoclonal antibodies raised against human intestinal and human tissue-unspecific alkaline phosphatase (AP) were developed and were used to study the expression of these two isoenzymes in human renal tissue and their release into urine. Approximately 25% of the total AP content of renal tissue at the transition between cortex and medulla was of the intestinal type; the remainder was of the tissue-unspecific type (liver, bone, kidney AP). Immunoperoxidase staining using specific monoclonal antibodies against liver and intestinal AP revealed that the tissue-unspecific AP isoenzyme is present through-out the different segments of the proximal tubule, whereas intestinal-type AP is found exclusively in tubuloepithelial cells of the S3-segment of the proximal tubule. The intestinal-type enzyme obtained from the kidney had a similar heat stability and Km value, and similar immunologic and inhibitory (L-p-bromotetramisole; L-phenylalanine) characteristics compared to adult intestinal and fetal intestinal AP. Its electrophoretic mobility in agarose gel was intermediate between that of adult intestinal and fetal intestinal AP; after neuraminidase treatment it became indistinguishable from the adult intestinal isoenzyme. The intestinal-type AP found in the urine was not sensitive to neuraminidase and had a molecular weight significantly lower than the urinary tissue-unspecific AP isoenzyme. In conclusion, intestinal AP in the kidney is a specific marker for the brush border of the S3 segment of the proximal tubule, and this finding opens new perspectives in the cell biology of this particular part of the nephron.

Radiolocalisation and imaging of stably HPLAP-transfected MO4 tumours with monoclonal antibodies and fragments.

Immunotargeting of PLAP-expressing tumours was studied for two radioiodinated, highly specific anti-PLAP monoclonal antibodies, 7E8 and 17E3, differing 10-fold in affinity, as well as for 7E8 F(ab')2 fragments. An anti-CEA monoclonal antibody or anti-CD3 F(ab')2 fragments were used as controls. Specific and non-specific targeting was examined in nude mice simultaneously grafted with PLAP-positive tumours derived from MO4 1-4 cells, and CEA-positive tumours, derived from 5583-S cells. Results indicated that (1) MO4 1-4 tumours, with a stable expression of PLAP on the plasma membrane, represent a useful new in vivo model for immunodirected tumour targeting; (2) differences in antibody affinity for PLAP in vitro are not reflected in antibody avidity for tumour cells in vivo; and (3) excellent selective and specific localisation of the PLAP-positive tumours is achieved when 7E8 F(ab')2 fragments are used. The high tumour/blood ratios (10.7 +/- 3.9 at 46 h after injection) were due to a much faster blood clearance of 7E8 F(ab')2 fragments. At this time point, the mean tumour/non-tumour tissue ratio was as high as 34.5, and the mean specific localisation index was 29.0. As expected, the F(ab')2 fragments provided high tumour imaging efficiency on gamma camera recording. These data imply important potentials of the PLAP/anti-PLAP system for immunolocalisation and therapy in patients, but also emphasise that in vitro criteria alone are not reflected in in vivo tumour localisation capacities of antibodies.