A carcinoembryonic antigen (CEA) specific monoclonal hybridoma antibody that reacts only with high-molecular-weight CEA

Napsin A levels in epithelial lining fluid as a diagnostic biomarker of primary lung adenocarcinoma

BACKGROUND

It is crucial to develop novel diagnostic approaches for determining if peripheral lung nodules are malignant, as such nodules are frequently detected due to the increased use of chest computed tomography scans. To this end, we evaluated levels of napsin A in epithelial lining fluid (ELF), since napsin A has been reported to be an immunohistochemical biomarker for histological diagnosis of primary lung adenocarcinoma.

METHODS

In consecutive patients with indeterminate peripheral lung nodules, ELF samples were obtained using a bronchoscopic microsampling (BMS) technique. The levels of napsin A and carcinoembryonic antigen (CEA) in ELF at the nodule site were compared with those at the contralateral site. A final diagnosis of primary lung adenocarcinoma was established by surgical resection.

RESULTS

We performed BMS in 43 consecutive patients. Among patients with primary lung adenocarcinoma, the napsin A levels in ELF at the nodule site were markedly higher than those at the contralateral site, while there were no significant differences in CEA levels. Furthermore, in 18 patients who were undiagnosed by bronchoscopy and finally diagnosed by surgery, the napsin A levels in ELF at the nodule site were identically significantly higher than those at the contralateral site. In patients with non-adenocarcinoma, there were no differences in napsin A levels in ELF. The area under the receiver operator characteristic curve for identifying primary lung adenocarcinoma was 0.840 for napsin A and 0.542 for CEA.

CONCLUSION

Evaluation of napsin A levels in ELF may be useful for distinguishing primary lung adenocarcinoma.

Location of biomarkers and reagents within agarose beads of a programmable bio-nano-chip

The slow development of cost-effective medical microdevices with strong analytical performance characteristics is due to a lack of selective and efficient analyte capture and signaling. The recently developed programmable bio-nano-chip (PBNC) is a flexible detection device with analytical behavior rivaling established macroscopic methods. The PBNC system employs ≈300 μm-diameter bead sensors composed of agarose "nanonets" that populate a microelectromechanical support structure with integrated microfluidic elements. The beads are an efficient and selective protein-capture medium suitable for the analysis of complex fluid samples. Microscopy and computational studies probe the 3D interior of the beads. The relative contributions that the capture and detection of moieties, analyte size, and bead porosity make to signal distribution and intensity are reported. Agarose pore sizes ranging from 45 to 620 nm are examined and those near 140 nm provide optimal transport characteristics for rapid (<15 min) tests. The system exhibits efficient (99.5%) detection of bead-bound analyte along with low (≈2%) nonspecific immobilization of the detection probe for carcinoembryonic antigen assay. Furthermore, the role analyte dimensions play in signal distribution is explored, and enhanced methods for assay building that consider the unique features of biomarker size are offered.

Nano-bio-chips for high performance multiplexed protein detection: determinations of cancer biomarkers in serum and saliva using quantum dot bioconjugate labels

The integration of semiconductor nanoparticle quantum dots (QDs) into a modular, microfluidic biosensor for the multiplexed quantitation of three important cancer markers, carcinoembryonic antigen (CEA), cancer antigen 125 (CA125), and Her-2/Neu (C-erbB-2) was achieved. The functionality of the integrated sample processing, analyte capture and detection modalities was demonstrated using both serum and whole saliva specimens. Here, nano-bio-chips that employed a fluorescence transduction signal with QD-labeled detecting antibody were used in combination with antigen capture by a microporous agarose bead array supported within a microfluidics ensemble so as to complete the sandwich-type immunoassay. The utilization of QD probes in this miniaturized biosensor format resulted in signal amplification 30 times relative to that of standard molecular fluorophores as well as affording a reduction in observed limits of detection by nearly 2 orders of magnitude (0.02 ng/mL CEA; 0.11 pM CEA) relative to enzyme-linked immunosorbent assay (ELISA). Assay validation studies indicate that measurements by the nano-bio-chip system correlate to standard methods at R(2)=0.94 and R(2)=0.95 for saliva and serum, respectively. This integrated nano-bio-chip assay system, in tandem with next-generation fluorophores, promises to be a sensitive, multiplexed tool for important diagnostic and prognostic applications.

Tumor-associated antigen expression and growth requirements predict tumorigenesis in squamous cell carcinoma

Squamous cell carcinomas (SCCs) are the most common malignancies in man. While clinical specimens are theoretically ideal to study tumor development and progression, practical difficulties such as normal cell contamination, the presence of different cell types. and limited material make preclinical studies of model systems involving a homogeneous population of normal or transformed cells preferable. Tumor-associated antigens (TAAs) found on the cell surface, including integrins, mucins, cadherins, growth factor receptors, membrane bound antigens, and glycoproteins are known to play an important role in squamous carcinogenesis. We hypothesized that (1) alterations in TAA expression in vitro predict in vivo alterations, (2) analysis of a group of TAAs would provide a better indication of SCC tumorigenesis than any single marker, and (3) SCCs with independence from exogenous growth factors in vitro would demonstrate the most aggressive growth in vivo. The cell line which grew best in vitro without serum or other supplements demonstrated the most rapid tumor growth. whereas cell lines which grew only with supplements rarely formed tumors. Normal keratinocytes. eight SCC and two immortal keratinocyte cell lines were evaluated by flow cytometry for the expression of 10 cell surface markers, including alpha and beta integrins, minor blood group-related carbohydrate determinants. carcinoembryonic antigen-related proteins, E-cadherin, and GA733 (epithelial glycoprotein. epithelial cell adhesion molecule). None of the cell lines with abnormal expression of < or = 2 markers formed tumors, whereas all lines with altered expression of > or = 3 markers formed tumors. Using GA733 expression as an example, we found that altered TAA expression in vitro predicted the presence of TAA alterations in clinical specimens. In summary, in vitro independence from supplements for optimal growth and altered expression of > or = 3 cell surface markers were good predictors of SCC tumorigenesis. These findings may be useful in decreasing the need for whole animal tumorigenicity experiments.

Clinical and immune responses in resected colon cancer patients treated with anti-idiotype monoclonal antibody vaccine that mimics the carcinoembryonic antigen

PURPOSE

We generated an anti-idiotype antibody, designated CeaVac, that is an internal image of the carcinoembryonic antigen (CEA). We previously demonstrated that the majority of patients with advanced colorectal cancer generate specific anti-CEA responses. The purpose of the current study was to treat patients with surgically resected colon cancer with CeaVac to determine the immune response and clinical outcome to treatment with vaccine. We also compared the immune responses between patients treated with fluorouracil (5-FU) chemotherapy regimens plus vaccine versus vaccine alone.

PATIENTS AND METHODS

Thirty-two patients with resected Dukes' B, C, and D, and incompletely resected Dukes' D disease were treated with 2 mg of CeaVac every other week for four injections and then monthly until tumor recurrence or progression. Fourteen patients were treated concurrently with 5-FU chemotherapy regimens.

RESULTS

All 32 patients entered onto this trial generated high-titer immunoglobulin G and T-cell proliferative immune responses against CEA. The 5-FU regimens did not have a qualitative or quantitative effect on the immune response. Three of 15 patients with Dukes' B and C disease progressed at 19, 24, and 35 months. Seven of eight patients with completely resected Dukes' D disease remained on study from 12 to 33 months; one patient with resected Dukes' D disease relapsed at 9 months. One patient with incompletely resected Dukes' D disease remained on study at 14 months without evidence of progression; eight experienced disease progression at 6 to 31 months.

CONCLUSION

CeaVac consistently generated a potent anti-CEA humoral and cellular immune response in all 32 patients entered onto this trial. A number of very high-risk patients continue on study. 5-FU regimens, which are the standard of care for patients with Dukes' C disease, did not affect the immune response. These data warrant a phase III trial for patients with resected colon cancer.

Bilateral breast cancer: one disease or two?

Our purpose was to determine whether bilateral breast cancer depends upon genetic predisposition to multiple tumors or, alternatively, represents two independent sporadic events. Biological concordance of hormone receptors and histopathology in bilateral tumors, family history of breast cancer, age at diagnosis, and survival were evaluated in 88 patients. The immunoreactivity of paired tumors from 51 patients to six different immunocytochemical markers was compared. Neither histologic patterns nor immunocytochemical reactions showed concordance between bilateral tumors. Absence of concordance (other than for estrogen receptors) and lack of associations with positive family history and early age of onset support an interpretation of independent tumor origins and does not suggest a major role for genetic determinants in the majority of cases of bilateral breast cancer.

Anti-idiotype monoclonal antibodies as vaccines for human cancer

The anti-idiotype therapy approach has been tested and has shown to be effective in several animal models including the L1210/GZL tumor system in DBA/2 mice. Very recently, anti-idiotype antibodies (Ab2) have also been used in human trials. In this review, the generation and characterization of Ab2s which can be used as potential vaccine candidates for two human tumor systems--leukemia/lymphona and gastrointestinal carcinoma have been discussed. We have generated syngeneic monoclonal idiotypic cascades for two different human tumor-associated antigens (TAA) gp37 and carcinoembryonic antigen (CEA). In both cascades we have produced TAA mimicking monoclonal Ab2s and monoclonal anti-anti-idiotypes (Ab3) which bind to the original TAA. Modulation of immune responses in cancer patients by Ab2 immunization will be an important consideration in future studies.

Murine monoclonal antibodies in breast cancer: an overview

Monoclonal antibody technology has been an important development in breast cancer research. Monoclonal antibodies do not detect 'breast cancer specific' antigens but, rather, they react with normal or modified tissue antigens which are either preferentially or inappropriately expressed upon malignant cells. Thus far a number of monoclonal antibodies that have a preferential reaction with breast cancer tissue have been developed. They have a potential value in immunohistopathology as diagnostic tools and in the recognition of small quantities of malignant cells, in the development of serum assay for tumour markers in breast cancer and in the radio-immunodetection of metastases. There has been success in effecting selective targeting of anticancer agents (cytotoxic drugs, toxins, radionuclides) to tumour deposits and encouraging results are obtained in preclinical in vivo studies. Various clinical studies are now in progress to evaluate the role of monoclonal antibodies in the management of breast cancer.

Monoclonal antibodies to breast cancer-associated antigens as potential reagents in the management of breast cancer

Monoclonal antibodies reactive with the surface of human breast carcinoma cells have been generated and characterized. The immunogens used were membrane-enriched fractions of metastatic carcinoma lesions. The various monoclonals were shown to react with previously known as well as with novel tumor-associated antigens (TAAs). The most specific of the latter group is monoclonal B72.3, which is reactive with a 220,000 to 400,000 high-molecular-weight glycoprotein complex found in 50% of human mammary carcinomas and 80% of human colon carcinomas. Monoclonal antibody B6.2, which recognizes a 90,000-d glycoprotein, was radiolabeled and shown to efficiently localize human carcinoma transplants in athymic mice via gamma imaging without the use of second antibody or background subtraction manipulations. F(ab')2 and Fab' fragments were shown to be more efficient for tumor localization than intact immunoglobulin. Whereas the phenomenon of antigenic heterogeneity of tumor cell populations has long been known to exist, this phenomenon was also shown to manifest itself as antigenic modulation, in which specific TAAs can modulate their expression on the cell surface concurrent with different phases of the cell cycle. A phenomenon known as antigen evolution, in which a specific cloned tumor cell population can gradually drift in antigenic phenotype, has also been demonstrated. Recombinant interferon has been employed to (1) enhance the expression of specific TAAs on the surface of tumor cells already expressing the antigen; and (2) induce the expression of specific TAAs on the surface of carcinoma cells not previously expressing the antigen. The clinical implications of such phenomena in gamma scanning for the detection of tumor masses and for tumor immunotherapy are discussed. Methods for circumvention of problems inherent in the clinical use of monoclonal antibodies are also addressed.

Binding of five monoclonal anti-CEA antibodies with different epitope specificities to various carcinoma tissues

Five monoclonal antibodies that recognize different epitopes on carcinoembryonic antigen (CEA) were reacted with tissue sections of various carcinoma specimens. The vital, non-necrotic tissues of those carcinomas of the oesophagus, pancreas, colon and rectum, medullary thyroid, ovary and cervix in which CEA related epitopes were detectable bound all five antibodies to a similar degree. In 3/5 lung carcinomas, 2/10 mammary carcinomas and 1/5 gastric carcinomas, a significantly different binding of the monoclonal antibodies by vital tumour tissue was present as determined by three independent investigators. In necrotic tissue areas, heterogeneity of antibody binding was more common. In a previous investigation, it was shown that normal granulocytes and liver tissue differentially bind the monoclonal anti-CEA antibodies, indicating the presence of crossreacting antigens. The equivalent binding of the five monoclonal anti-CEA antibodies to most of the carcinomas tested suggests that this binding is due to the presence of complete CEA molecules and not only of cross-reacting antigens.

Immunochemical identification of an alpha 1-acid glycoprotein-antigenic determinant on carcinoembryonic antigen (CEA) and non-specific cross-reacting antigen (NCA)

An immunochemical characterization of carcinoembryonic antigen (CEA) and NCA (non-specific cross-reacting antigen) was performed. Positive reactions of CEA and NCA (Mr 60 000) with some antibodies to alpha 1-acid glycoprotein (AG) were observed. Thus, both antigens may contain immune determinants in common with alpha 1-acid glycoprotein. CEA showed positive reactivity with anti-NCA. NCA showed positive reactivity with either polyclonal or monoclonal antibodies to CEA, but negative reactivity with auto-antibodies to CEA. 125I-Tetracosapeptide (synthetic peptide-24 corresponding to the amino terminal sequence of CEA) failed to react with any antisera against CEA, NCA and AG. 125I-AG also showed no immuno-reaction with any antibody against CEA, NCA and tetracosapeptide. These results suggest that some monoclonal antibodies to CEA are directed against a common antigenic determinant of both CEA and NCA in addition to AG and tetracosapeptide, and that the auto-antibody to CEA is directed against a unique immune determinant which is not common to NCA. Thus, CEA appears to contain a unique determinant not found in NCA. Similarities in the composition of both amino acids and carbohydrates of CEA and NCA suggest that CEA is 'big-big' AG and NCA is 'big' AG.

Monoclonal antibodies in urology

The recent development of hybridoma technology has made it possible to obtain large quantities of antibody against a single determinant (monoclonal antibodies). This review describes the history of hybridoma technology and the method of producing monoclonal antibodies. It examines the role of such antibodies in diagnosis, tissue typing, histochemistry, developmental biology and study and treatment of diseases, including cancer, emphasizing the work being done on urological diseases.

Binding studies on two different monoclonal antibodies raised against CEA

Binding characteristics of two mouse monoclonal antibodies MA/1 and MA/200 raised to carcinoembryonic antigen (CEA) are presented. Double antibody radioimmunoassay and a solid phase assay confirmed that MA/1 binds weakly to CEA extracted from tumour tissue but strongly to CEA in patients' serum. Antibody MA/200 binds with high affinity to both 'tumour' and 'serum' CEA. Ligand-receptor relationship for MA/1 and MA/200 binding to both tumour CEA and CEA isolated from serum are presented from equilibrium binding data analysed by the method of Scatchard. Co-titration experiments also indicated that MA/1 and MA/200 and an established polyclonal anti-CEA bind to a similar subpopulation of CEA or CEA-like molecules, but the binding data demonstrate that their respective binding sites are chemically different.

Detection of carcinoembryonic antigen and related antigens in sera of patients with gastrointestinal tumors using monoclonal antibodies in double-determinant radioimmunoassays

Of 14 monoclonal antibodies produced in six different laboratories, 13 bound to purified preparations of carcinoembryonic antigen (CEA). All antibodies reacted to spent medium of colorectal carcinoma cell lines. Competitive binding studies indicated that 12 different antigenic determinants representing six different groups were detected on the CEA molecule(s). Six antibodies were used in double determinant radioimmunoassays (RIA) to detect CEA and CEA-related antigens in sera of 311 patients with various gastrointestinal diseases and of normal donors. None of up to 115 sera of healthy donors had elevated antigen levels with four out of the six monoclonal antibodies tested, whereas up to 9% of sera showed elevated antigen levels when tested with two antibodies. Between 1.4% and 4.4% of sera from patients with inflammatory and benign neoplastic diseases of the gastrointestinal tract were positive. Antigen levels were elevated in 56 to 75% (depending on antibody used) of sera from patients with advanced gastrointestinal tumors. These preliminary results indicate that double-determinant immunoassays with a panel of monoclonal antibodies might improve conventional CEA assays by reducing the number of false positive sera detected by polyclonal sera in patients with benign inflammatory bowel diseases.

Differential binding to human mammary and nonmammary tumors of monoclonal antibodies reactive with carcinoembryonic antigen

Splenic lymphocytes of mice immunized with membrane enriched fractions of human mammary carcinomas were fused with the NS-1 nonsecretory++ myeloma cell line. The resulting hybridomas were screened for the synthesis of immunoglobulins reactive with human mammary tumor associated antigens, and two IgG monoclonal antibodies (B1.1 and F5.5) were identified as being reactive with purified carcinoembryonic antigen (CEA). These antibodies were shown to bind to different epitopes on CEA based on their differential reactivities to five different purified CEA preparations, and their differential binding to the surface of tumor cells derived from various organ sites. Monoclonal B1.1 bound equally to the surface of human breast, colon, and melanoma cell lines. Monoclonal F5.5, on the other hand, did not react with the surface of melanoma cell lines, and showed a differential binding to breast carcinoma versus colon carcinoma cells. Monoclonals F5.5 and B1.1 were both used in immunoperoxidase studies with fixed tissue sections of a variety of histologic types of human mammary carcinomas and were shown to be reactive with 55% and 66%, respectively, of tumor masses.

Hybridomas: a new dimension in biological analyses

Since the first report of hybridomas producing monoclonal antibodies by Kohler and Milstein in 1975, this technique has spread to nearly all areas of biological, biochemical, and biomedical research. Watching the use of these methods spread from immunologists to cell biologists, developmental biologists, biochemists and to other biological disciplines and observing the nearly logarithmic increase in publications using these reagents has been in itself fascinating and informative. An overview of the development of this technology and its applications is presented including the use of monoclonal antibodies to study cell surface molecules, differentiation antigens, receptors, and histocompatibility antigens. The use of these antibodies to analyze microorganisms and parasitic antigens as well as their use in the genetic analysis of human cell surface antigens and the detection of polymorphic variation in enzymes and other proteins is discussed. Examples of the application of monoclonal reagents to the study of tumor cell biology including the labeling of metastatic tumor cells and the detection of cell surface molecules implicated in the regulation of growth control and cell division are provided.