Isolation and amino terminal sequencing of a novel melanoma-associated antigen

The biochemical characteristics are described for a melanoma-associated glycoprotein antigen, whose expression depends on stage of tumor progression and melanocytic differentiation. This antigen, identified using a monoclonal antibody which specifically stains melanoma cells in immunoperoxidase assay of fixed tissue sections, is synthesized as a 30,000-Da precursor and then processed to a 30,000- to 60,000-Da sialylated glycoprotein. Two-dimensional gel electrophoresis of the antigen resolved more than 20 forms, heterogeneous in both charge and molecular weight. The kinetics of post-translational processing, the sensitivity of processing to tunicamycin, and the molecular weight of the oligosaccharide chains indicate that the oligosaccharides are N-linked. Amino acid sequencing of the antigen purified by immunoaffinity chromatography and by high-pressure liquid chromatography or polyacrylamide gel electrophoresis allowed the assignment of the first 20 acids.

Metastatic uveal melanoma. Hepatic metastasis identified by hybridoma-secreted monoclonal antibody MAb8-1H

Monoclonal antibody MAb8-1H, which defines an ocular melanoma-associated antigen retained in fixed tissue, was used to demonstrate metastatic melanoma cells in liver biopsy specimens from five patients with primary choroidal melanoma. In all cases, the monoclonal antibody bound to tumor cells and not to normal hepatocytes. In one case, a well-delineated focus of tumor cells bound to MAb8-1H; in two cases, MAb8-1H appeared to delineate individual tumor cells that were difficult to categorize by conventional staining techniques. The liver biopsy specimens were almost completely replaced by tumor cells in the remaining two cases. This monoclonal antibody may be applicable to the diagnosis of metastatic uveal melanoma and to delineate micrometastasis.

Circulating tumor markers and assessment of response to intrahepatic chemotherapy of colon carcinoma

To assess the change in concentrations of circulating gastrointestinal cancer-associated antigens in response to therapy, we analyzed the sera of patients with hepatic metastasis from colorectal carcinoma who were treated with intrahepatic arterial chemotherapy. Serial serum samples were assessed for the tumor-associated antigens, carcinoembryonic antigen (CEA) and the gastrointestinal cancer antigen CA 19-9. Computed axial tomographic (CAT) scans were made to assess the size of the hepatic metastasis. In 9/10 of these patients the CEA predicted tumor response within 2-6 weeks after initiation of treatment, and in 7/10 the information was supported or more dramatically demonstrated by the CA 19-9. Combining data from both tumor markers may provide a more accurate assessment of the clinical response than one antigen alone. Recurrence of hepatic metastatic growth or extrahepatic tumor also was identified by elevation of one or both circulating tumor-associated antigens prior to other laboratory or clinical evidence of tumor growth.

Monoclonal antibody to a highly glycosylated protein reacts in fixed tissue with melanoma and other tumors

A highly glycosylated protein with a molecular weight of 30,000 to 60,000 and a protein core of 20,000 daltons has been identified by antimelanoma monoclonal antibodies. The antigenicity of this melanoma-associated glycoprotein (MAG) was not destroyed in fixed paraffin-embedded melanoma tissue, and was present in malignant cells of cutaneous superficial spreading melanomas in skin (31/33) and in half of all metastatic melanomas examined (5/10). The antigen was not expressed by normal melanocytes. The strong reactivity of dysplastic nevi with the anti-MAG antibodies was comparable to that seen in radial growth phase melanoma. Antigen expression was much weaker in compound nevi where reactivity ranged from moderate in the junctional component and the upper dermis to absent at the base of the nevus.

Monoclonal antibody localization of A and B isoantigens in normal and malignant fixed human tissues

The expression of human blood group A and B isoantigens in normal and malignant tissues from stomach, colon, and pancreas was analyzed in an immunoperoxidase assay using monoclonal antibodies specific for these isoantigens. Appropriate isoantigen expression was demonstrated in the normal epithelium from the stomach, pancreas, and proximal but not distal colon of blood group A, AB, or B patients. Half of all gastric carcinomas and of proximal colon carcinomas showed complete loss of isoantigen, whereas the adjacent mucosa in these cases continued to express appropriate isoantigen. Isoantigen expression was completely lost in only 13% of pancreatic carcinomas tested. Neither A nor B isoantigen was detected in normal epithelium from the distal colon. By contrast, 85% of carcinomas derived from this site showed reexpression of isoantigen. Inappropriate expression of A isoantigen was detected in pancreatic carcinomas (2/5) but not in gastric or colon carcinomas (0/21). Inappropriate expression of B substance was not detected in any tissue (0/38). Interestingly, differential binding of antibodies to Type 1 versus Type 2 and/or difucosyl versus monofucosyl blood group B substances was manifested by differences in intensity of staining for endothelium and red blood cells.

Characterization of nerve growth factor receptor in neural crest tumors using monoclonal antibodies

The nerve growth factor (NGF) receptor was characterized by using a new series of anti-receptor monoclonal antibodies (MAbs). These MAbs (i) showed significantly greater reactivity with a melanoma cell line expressing higher levels of NGF receptor, (ii) inhibited the binding of 125I-labeled NGF to its receptor, and (iii) immunoprecipitated both metabolically labeled and 125I-labeled NGF affinity-labeled receptor. These experiments defined the receptor as a 75-kDa cell-surface protein. The NGF receptor was visualized by immunoperoxidase staining in tissue sections of human nevi, melanomas, neurofibromas, a pheochromocytoma, and peripheral nerves. Uniform staining of the cytoplasm suggests that, in addition to cell-surface NGF receptors, there is a population of intracellular receptors.

Efficient selection of human tumor growth-inhibiting monoclonal antibodies

A method is described for selection early after fusion for hybridomas that secrete IgG2a monoclonal antibodies (MAbs) with binding specificity for antigens on the human tumor cells used to immunize mice. By combining this preselection method with antibody-dependent macrophage-mediated cytotoxicity assays, it was possible to select those MAbs mediating a tumoricidal effect against tumor cells in culture and inhibiting the growth of tumor xenografts in nude mice. Two such MAbs, GA733 and CO441, inhibited the growth of colorectal carcinoma cells, and one of them (GA733) was effective even when administered 6 days after implantation of tumor cells. These results suggest the potential usefulness of the 2 MAbs in immunodiagnosis and immunotherapy of human tumors.

Immunoassay for melanoma-associated proteoglycan in the sera of patients using monoclonal and polyclonal antibodies

A melanoma-associated proteoglycan antigen is expressed by primary cutaneous and ocular melanomas, metastatic melanomas, nevus cells, some astrocytomas, and fetal fibroblasts, and it is shed into culture supernatant by both melanoma and nevus cells. The antigen is also expressed by tumor cells in vivo. Melanoma and nevus cells, but not normal melanocytes, were specifically stained by the immunoperoxidase procedure. The proteoglycan antigen, purified by immunoaffinity chromatography using a monoclonal antibody that specifically detects this antigen, was used to immunize rabbits. The resulting serum was tested by sequential immunoprecipitation and found to react with the same population of molecules detected by the anti-proteoglycan monoclonal antibodies. Furthermore, the reactivity patterns of the rabbit serum and of the monoclonal antibodies with a variety of tumor and normal cells were the same. Based on the these data, we conclude that the entire proteoglycan molecule is a melanoma-associated antigen. The monoclonal antibodies and immunoglobulin from the rabbit serum were tested in a double determinant immunoassay for the detection of antigen in a total of 339 sera from patients with various diseases. Elevated levels of circulating proteoglycan antigen were found in 76% of patients with a high metastatic melanoma tumor burden compared to 2% of healthy donors. A fraction (22%) of patients with light tumor burden or nonmelanoma neoplastic disease also had elevated levels of circulating proteoglycan antigen. The source of the antigen for the latter patients may be collagenous connective tissue which, as judged by immunoperoxidase staining, expresses the antigen in both normal and transformed tissues.

Production and characterization of monoclonal antibodies to peripheral and central nervous system myelin

Monoclonal antibodies against P0, myelin basic protein, or myelin-associated glycoprotein were generated by fusing mouse myeloma cells with spleen cells from BALB/c mice immunized with central and peripheral nervous system myelin proteins. The antibodies secreted were either IgG, IgM, or IgA. Clone C6B5 (iso-type IgM) secreted antibody(ies) that bound to both myelin basic protein and myelin-associated glycoprotein, although binding of antibody to myelin basic protein as detected by the immunoblot technique appeared to be much less than to the myelin-associated glycoprotein. Antibodies were characterized in solid-phase radioimmunoassay for their species cross-reaction, and histologically for the specificity of binding to myelin in central and peripheral nervous system tissues. These monoclonal reagents should prove valuable in studying CSF and myelin-producing cells, since in both cases the concentration of myelin proteins is low.

Identification of melanoma-associated antigens using fixed tissue screening of antibodies

Early culture supernatants from hybridomas that were obtained through fusions of mouse myeloma cells with lymphocytes of melanoma-immunized mice were screened for their reactivity with a paraffin-embedded cell block of a melanoma cell line, using a biotin:avidin immunoperoxidase procedure. Eleven monoclonal antibodies were derived that define several new melanoma-associated antigens. The antigens include a neutral glycolipid, gangliosides, membrane-associated proteins, cytosolic proteins, and strongly secreted proteins. These antibodies, which detect antigens that withstand tissue fixation and embedding procedures, were tested for reactivity in fixed cell lines, as well as in melanoma biopsies. These antibodies may provide powerful tools in diagnostic studies of human malignant melanoma biopsy material.

Bactericidal effect of polymorphonuclear neutrophils on antibiotic-induced filaments of gram-negative bacilli

Exposure of strains of Escherichia coli to ampicillin and mezlocillin and of strains of Pseudomonas aeruginosa to azlocillin and cefsulodin caused the bacilli to elongate into filaments. The bacilli and their filaments were incubated with fresh human polymorphonuclear neutrophils (PMNs), and the phagocytic process was recorded by means of phase-contrast microscopy. The bactericidal effect of PMNs on both filaments and bacilli was quantitated by counts of colony-forming units. A single PMN phagocytized one or more filaments, some of which were as long as 90 micron and contained as many as 20 genomes. Two predominant patterns of phagocytosis of filaments were observed. When the ratio of bacteria to PMNs was low (0.2-1.8), the rate of killing was 62%-81%. When the ratio was higher (5-12), the rate of killing of both filaments and bacilli was lower. As an alternative to colony-forming units, cell mass was used as a gauge of phagocytic activity. The relative mass of killed filaments was considerably greater than that of killed bacilli; this finding indicated that filaments were much more susceptible than were bacilli to the bactericidal activity of PMNs.

Binding of murine immunoglobulin to human tissues after immunotherapy with anticolorectal carcinoma monoclonal antibody

An anticolorectal carcinoma antibody, 17-IA, that is of gamma 2a isotype and has been used in previous immunotherapy trials, binds to an antigen on most human colon tumors. This antigen is destroyed by the fixative and embedding procedures employed for routine histologic evaluation of tissues. It can be demonstrated by the avidin/biotin-labelled peroxidase complex (ABC) immunoperoxidase technique on briefly fixed, frozen sections of fresh human tissues. With this assay technique, the antibody is found to bind in vitro to both human colonic carcinoma and normal gastrointestinal epithelia. Tissues removed from patients having received the 17-IA antibody intravenously in an immunotherapy trial show bound antibody 1-2 after administration. This is no longer evident 3 weeks later though the antigen is present on the cell surface and is still capable of binding antibody in vitro.

Monoclonal antibody localization of Lewis antigens in fixed tissue

Monoclonal antibodies that bind specifically with Lewisa (Lea) and Lewisb (Leb) antigens were used in an immunoperoxidase assay to characterize Lewis (Le) antigenic profile of a variety of fixed tissues. Representative sections of normal and malignant tissue from the stomach, colon, pancreas, and kidney were examined and compared. Lea antigen was expressed more often in gastric adenocarcinomas (80%) than normal gastric mucosa (40%). In gastric tumors with concomitant expression of Le antigens, larger areas within an individual tumor expressed Lea antigen rather than Leb antigen. Expression of Leb antigen in normal colonic tissue was seen only in the proximal colon and not distal colon; colon carcinomas, on the other hand, expressed Leb antigen (64%) regardless of where the primary arose. Leb antigen was expressed in large pancreatic ducts (three of three) more often than Lea antigen (one of three); exclusive expression of Lea antigen was demonstrated in the proximal convoluted tubules of normal kidney (three of three) and in renal cell carcinomas (six of eight).

Peritoneal washing cytology. Uses and diagnostic criteria in gynecologic neoplasms

Review of a 20-month experience with 241 peritoneal washes performed on 191 patients showed that the use of these specimens has expanded greatly. Of the 19 patients with neoplastic cells in their peritoneal washing cytology specimens, 12 had primary ovarian neoplasms, 4 had primary uterine cervical neoplasms, 2 had primary endometrial neoplasms, and 1 had mammary carcinoma metastatic to the ovary. Gynecologic oncologists at this institution are now routinely obtaining peritoneal washing cytology specimens whenever there is intraabdominal surgery on patients known to have or suspected of having a pelvic neoplasm. The following criteria were found to be essential to the accurate evaluation of these specimens: (1) cells considered to be malignant should be present both singly and in groups and should be malignant by the usual cytologic criteria, (2) the patients must have or be known to have had a neoplasm whose cells are similar to those in the washing specimen, and (3) the cells considered to be neoplastic must be different from and not confused with reactive mesothelial cells. The last criterion is important because the peritoneal lavage traumatically removes mesothelium, which can appear atypical. These criteria make the cytologic interpretation of most peritoneal washing specimens straightforward; interesting diagnostic problems occur, however, including the evaluation of neoplasms of borderline malignancy, those "spilled" during surgery and second neoplasms found by peritoneal washing cytology.

Arithmetic remediation and the learning disabled adolescent: fractions and interest level

This article suggests that work with fractions is a viable way to deal with fundamental computation deficiencies. Keeping in mind the mathematical “interest level” of beginning secondary students, the article proposes that learning disabled adolescents start remedial work with fractions. A fractions task analysis is provided along with specific suggestions for drill material.

Effect of Rifampin and Oxacillin on the Ultrastructure and Growth of Staphylococcus aureus

The minimal inhibitory concentrations (MICs) of rifampin for 12 strains of Staphylococcus aureus ranged from 0.005 microgram/ml to 0.02 microgram/ml, and the minimal antibiotic concentrations (i.e., those that inhibited growth by 90% in comparison with control values) ranged from one-fifth to one-half the MICs. Rifampin alone produced a 1-log (90%) decrease in the staphylococcal population after incubation for 6.5 hr, and the inhibitory effect after removal of the antibiotic lasted for 5 hr. Regardless of whether rifampin was used simultaneously with, before, or after exposure to oxacillin, the latter drug partially or totally prevented the overgrowth of rifampin-resistant staphylococci. The use of this combination in therapy is therefore justified. Staphylococci exposed to rifampin at concentrations equal to three or 20 times the MIC developed a cell wall that was four times thicker than normal and had a peripheral undulated dense layer. The cross walls were also two to 10 times thicker than normal but had a normal central dense zone. Exposure of staphylococci to oxacillin produced large cells with multiple cross walls that underwent autolysis when the organisms were transferred to drug-free medium. When exposure to oxacillin was preceded by exposure to rifampin, cells did not become enlarged. When the large cells produced by oxacillin were transferred to medium containing rifampin, the cross walls did not lyse.

Mild cervical dysplasia. Experience in a family planning clinic

To evaluate mild cervical dysplasia, the results of Papanicolaou smears were reviewed for a six-month period in an inner-city family planning program. Papanicolaou smear evidence of mild dysplasia was consistent with the biopsy diagnosis in most cases. A single Papanicolaou smear is not a reliable indication of condylomata, nor is a single normal Papanicolaou smear in this setting completely reassuring. Persistent mild dysplasia is an indicator of high risk for cervical dysplasia and cervical infection. Aggressive initial cervical surgery is not indicated, but close follow-up is required.

Phagocytosis of filaments of Escherichia coli produced with mezlocillin

The phagocytosis of filaments of Escherichia coli produced with mezlocillin differs from the phagocytosis of normal bacilli in that pseudopods are employed for bacilli, but the entire body of the polymorphonuclear cell (PMN) participates in the engulfment of a filament. A single PMN was observed phagocytizing one or more filaments 20-50 micron long. The mass of a filament is about ten times larger than the mass of a bacillus. When equal bacterial mass, one filament or 10 bacilli, is exposed to PMNs comparable bacterial killing results after 2-3 h of incubation.

Monoclonal antibodies derived from immunosuppressed mice grafted with human melanoma

Hybridoma cells producing monoclonal antibodies against tumor-shed antigens were generated by fusing mouse myeloma cells with spleen cells from immunosuppressed mice bearing human melanoma xenografts. Thirty-eight fusion experiments were performed at different stages of tumor growth. Hybridomas producing anti-melanoma antibodies were obtained from 12 spleens in mice bearing 1-4-week-old tumors but at later stages of tumor growth, no hybridomas whatsoever could be obtained. However, the sera of all mice tested showed anti-melanoma antibody binding reactivity at the time of fusion. Using radioimmunoassay (RIA) to select specific antibody secreting hybridoma cultures, the majority of cultures were found to produce antibodies which bound to both 3 M KCl melanoma extracts and melanoma culture supernatants. No stable cultures secreting membrane-reactive (live tumor cell targets) antibodies could be obtained. All of the monoclonal antibodies bound not only to melanoma target cell preparations, but also to preparations from tumors of other origins and only 3 did not bind to normal human fibroblasts. The crossreactivity pattern of binding was confirmed in immunoperoxidase (IP) assays by binding to human tissue sections. The immunosuppressed mouse bearing human tumor xenografts has proven a useful system for production of monoclonal antibodies against antigens shed by tumor cells.