Biomolecular Recognition of the Glycan Neoantigen CA19-9 by Distinct Antibodies

Glycans decorate the cell surface, secreted glycoproteins and glycolipids, and altered glycans are often found in cancers. Despite their high diagnostic and therapeutic potential, however, glycans are polar and flexible molecules that are quite challenging for the development and design of high-affinity binding antibodies. To understand the mechanisms by which glycan neoantigens are specifically recognized by antibodies, we analyze the biomolecular recognition of the tumor-associated carbohydrate antigen CA19-9 by two distinct antibodies using X-ray crystallography. Despite the potential plasticity of glycans and the very different antigen-binding surfaces presented by the antibodies, both structures reveal an essentially identical extended CA19-9 conformer, suggesting that this conformer's stability selects the antibodies. Starting from the bound structure of one of the antibodies, we use the AbLIFT computational algorithm to design a variant with seven core mutations in the variable domain's light-heavy chain interface that exhibits tenfold improved affinity for CA19-9. The results reveal strategies used by antibodies to specifically recognize glycan antigens and show how automated antibody-optimization methods may be used to enhance the clinical potential of existing antibodies.

Antibodies targeting sialyl Lewis A mediate tumor clearance through distinct effector pathways

Sialyl Lewis A (sLeA, also known as CA19-9), a tetrasaccharide selectively and highly expressed on advanced adenocarcinomas including colon, stomach, and pancreatic cancers, has long been considered as an attractive target for active and passive vaccination. While progress in antibodies targeting tumor-associated protein antigens resulted in an impressive array of therapeutics for cancer treatment, similar progress in exploiting tumor-associated carbohydrate antigens, such as sLeA, has been hampered by the lack of a detailed understanding of the singular characteristics of these antigens. We have addressed this issue by analyzing antibodies derived from patients immunized with an sLeA/KLH vaccine. These antibodies were engineered to mediate tumor clearance in vivo in preclinical models through Fc-FcγR interactions. However, in contrast to protein antigens in which hFcγRIIIA engagement was both necessary and sufficient to mediate tumor clearance in both preclinical and clinical settings, a similar selective dependence was not seen for anti-sLeA antibodies. Thus, re-engineering the Fc portion of sLeA-targeting antibodies to broadly enhance their affinity for activating FcγRs led to an enhanced therapeutic effect. These findings will facilitate the development of more efficient anticancer therapies and further advance this promising class of therapeutic antibodies into clinical use.

Efficacy of irreversible electroporation ablation combined with natural killer cells in treating locally advanced pancreatic cancer

PURPOSE

To explore the efficacy and safety of irreversible electroporation (IRE) ablation combined with natural killer (NK) cells in the treatment of locally advanced pancreatic cancer (LAPC).

METHODS

A total of 92 LAPC patients treated in our hospital from January 2016 to January 2017 were enrolled, and there were 46 cases of percutaneous IRE as IRE group, and 46 cases of IRE combined NK cell therapy as IRE-NK group. The clinical information of all the patients was collected, and the short-term efficacy, changes in the serum immunological indicators after treatment, carbohydrate antigen 19-9 (CA19-9) level, and incidence of adverse reactions were compared between the two groups of patients. Besides, the overall survival (OS) and disease-free survival (DFS) of patients were followed up and recorded.

RESULTS

On 1 month after treatment, all the patients underwent efficacy assessment, which showed the overall response rate of patients in IRE-NK group was significantly superior to that in IRE group. One and 7 days after operation, the level of CA19-9 was obviously raised in the two groups, with a statistically significant difference, and it declined 30 days postoperatively. Seven and 30 days after operation IRE-NK group had a notably lower level of CA19-9 than IRE group. After treatment, all the patients exhibited considerably higher lymphocyte count and notably enhanced lymphocyte function, and all the indicators in IRE-NK group were higher than those in IRE group. Besides, the levels of serum interleukin (IL)-2, TNF-β and IFN-γ in IRE-NK group were remarkably higher than those in IRE group, whereas there were no statistically significant differences in the levels of IL-4, IL-6 and IL-10 between the two groups. All the patients were followed up for 6-29 months, and there were no statistically significant differences in the DFS and OS between IRE group and IRE-NK group.

CONCLUSION

IRE ablation combined with NK cells has excellent efficacy in treating LAPC, and they can exert a synergistic treatment effect to enhance the immune function of patients and reduce CA19-9 expression, with tolerable adverse reactions.

Toward Curative Fluorescence-Guided Surgery of Pancreatic Cancer

BACKGROUND/AIMS

Negative surgical margins are critical to prevent recurrence in cancer surgery. We review the use of fluorophore-labeled monoclonal antibodies to aid in cancer visualization in orthotopic nude mouse models of human pancreatic cancer in order to achieve negative margins in fluorescence-guided surgery (FGS).

METHODOLOGY

Anti-CEA or anti-CA 19-9 antibodies were conjugated with fluorophores of visible and near-infrared wavelengths. Orthotopic primary and metastatic human pancreatic tumors in nude mouse models were readily visualized with fluorescence imaging after administration of fluorophore conjugated anti-CEA or anti-CA 19-9.

RESULTS

The fluorescence signal was detectable 30 minutes after systemic antibody delivery and remained present for two weeks, with minimal in vivo photobleaching after exposure to standard operating room lighting. There was greatly improved ability to resect labeled tumor tissue using FGS.

CONCLUSIONS

Fluorophore-labeled anti-CEA or anti-CA 19-9 antibodies enable enhanced visualization of tumors for FGS of pancreatic cancer when CEA or CA 19-9 expression is present. The choice of fluorophore significantly affects the signal intensity in the labeled tumor. The technologies described herein have the potential to change the paradigm of surgical oncology to engender significantly improved outcomes.

Metastatic recurrence in a pancreatic cancer patient derived orthotopic xenograft (PDOX) nude mouse model is inhibited by neoadjuvant chemotherapy in combination with fluorescence-guided surgery with an anti-CA 19-9-conjugated fluorophore

The aim of this study is to determine the efficacy of neoadjuvant chemotherapy (NAC) with gemcitabine (GEM) in combination with fluorescence-guided surgery (FGS) on a pancreatic cancer patient derived orthotopic xenograft (PDOX) model. A PDOX model was established from a CA19-9-positive, CEA-negative tumor from a patient who had undergone a pancreaticoduodenectomy for pancreatic adenocarcinoma. Mice were randomized to 4 groups: bright light surgery (BLS) only; BLS+NAC; FGS only; and FGS+NAC. An anti-CA19-9 or anti-CEA antibody conjugated to DyLight 650 was administered intravenously via the tail vein of mice with the pancreatic cancer PDOX 24 hours before surgery. The PDOX was brightly labeled with fluorophore-conjugated anti-CA19-9, but not with a fluorophore-conjugated anti-CEA antibody. FGS was performed using the fluorophore-conjugated anti-CA19-9 antibody. FGS had no benefit over BLS to prevent metastatic recurrence. NAC in combination with BLS did not convey an advantage over BLS to prevent metastatic recurrence. However, FGS+NAC significantly reduced the metastatic recurrence frequency to one of 8 mice, compared to FGS only after which metastasis recurred in 6 out of 8 mice, and BLS+NAC with metastatic recurrence in 7 out of 8 mice (p = 0.041). Thus NAC in combination with FGS can reduce or even eliminate metastatic recurrence of pancreatic cancer sensitive to NAC. The present study further emphasizes the power of the PDOX model which enables metastasis to occur and thereby identify the efficacy of NAC in combination with FGS on metastatic recurrence.

[Preparation and characterization of the monoclonal antibodies against human CA19-9 and establishment of a sandwich CLIA system]

OBJECTIVE

To prepare the monoclonal antibodies (mAbs) against human carbohydrate antigen 19-9 (CA19-9) and establish a double-antibody sandwich chemiluminescent immunoassay (CLIA) detection system for CA19-9 in the human serum.

METHODS

BALB/c mice were immunized with human CA19-9 antigen. The mAbs were obtained by hybridoma technique. The purity, titer, specificity and pairing of the mAbs were characterized and the sandwich CLIA system was established. The system was evaluated in its accuracy, limit of detection, linearity and repetitiveness after optimization of coating buffer, coating concentration and pipetting mode, and the serum sample was tested with it.

RESULTS

Four mAbs named #1-1, #2-1, #3-1 and #4-1 were obtained against human CA19-9. The titers of the anti-CA19-9 mAbs were above 10(-8). The mAbs had nearly no cross-reaction with CA125, CA15-3 and CA72-4. The double-antibody sandwich CLIA system was established by #3-1 mAb and #2-1 mAb-HRP. After optimization, its property was detection range of 0-1 000 U/mL, limit detection of 2.0 U/mL, linear correlation coefficient of 0.9999. The results which were contrasted with Roche test showed that: Kappa>0.75, r(correlation coefficient)>0.9.

CONCLUSION

The mAbs against human CA9-9 have been prepared and a sandwich CLIA system for detecting CA19-9 in the human serum has been established successfully.

Hemothorax with a high carbohydrate antigen 19-9 level caused by a bronchogenic cyst

A 58-year-old man presented with right-sided chest pain. Radiography and computed tomography showed a pleural effusion in the right chest and a mass in the right hilum. Thoracentesis showed a hemothorax. The carbohydrate antigen (CA) 19-9 level in the pleural effusion was very high, requiring differentiation from malignancy. Positron emission tomography showed no significant fluorodeoxy glucose (FDG) accumulation. Magnetic resonance imaging revealed a cystic lesion. The tumor was resected for both a diagnosis and treatment. A pathological examination demonstrated a bronchogenic cyst. An immunohistochemical study suggested that the cyst was the source of the hemothorax and the high CA19-9 level.

Intralobar pulmonary sequestration associated with marked elevation of serum carbohydrate antigen 19-9

This report describes a 62-year-old man who experienced elevated serum carbohydrate antigen 19-9 (CA19-9) levels (>500 U/mL) for 4 years, and was finally diagnosed with right intralobar pulmonary sequestration. Surgery confirmed the presence an aberrant artery arising from the descending thoracic aorta and entering the right lower lobe basal segment. Immunohistochemistry demonstrated markedly positive staining of CA19-9 in the ciliated cylindrical epithelia, alveoli, and mucus in the cysts. After pulmonary resection, CA19-9 levels decreased to within a normal range. Therefore, the cause of the elevated serum CA19-9 levels in this case was almost certainly due to intralobar pulmonary sequestration.

False positive carbohydrate antigen 19-9 (CA19-9) results due to a low-molecular weight interference in an apparently healthy male

BACKGROUND

We investigated the presence of interference in a patient who had an elevated CA19-9 concentration using the ADVIA Centaur but results within reference limits with ROCHE Modular Analytics E170 and Brahms KRYPTOR analysers.

METHODS

We performed repeat analyses using the same (ADVIA Centaur) and alternate immunossays (Roche Modular Analytics E170 and Brahms KRYPTOR) on the patient's sample and investigated for known interferences. To determine the nature of the interference, we measured CA19-9 on the ADVIA Centaur after dilution experiments and after incubation with non-immune animal sera and in heterophilic blocking tubes (HBT). We also undertook polyethylene glycol precipitation, lectin inhibition experiments and gel filtration chromatography.

RESULTS

A curvilinear response to dilution was observed with the ADVIA Centaur. Other known interferences were excluded. Treatment with HBT or non-immune animal sera did not give clinically different results from untreated samples. There was only 0.59% recovery after PEG precipitation in the sample from the case patient. Lectin reduced the assay signal in four patient samples (recovery=1.9-14.1%) but not in the case patient (recovery=106.2%). Gel filtration studies suggested the presence of a low molecular weight (approximately 100 kDa) interference in the case patient's serum.

CONCLUSIONS

We report a novel mode of interference and show a non-CA19-9, low molecular-weight interference affecting the ADVIA Centaur CA19-9 immunoassay.

Interchangeability of measurements of CA 19-9 in serum with four frequently used assays: an update

BACKGROUND

CA 19-9 is a marker principally related to pancreatic and gall bladder cancer. Although its determination has no value in screening for these malignancies, it is used in post-operative monitoring and during chemotherapeutic treatment of confirmed disease. Measurements during follow-up must be comparable and must be performed with standard, validated methods.

METHODS

We compared four routinely used analytical systems for CA 19-9 determination: the Architect i2000 and AxSYM systems from Abbott Laboratories, the Elecsys 1010 from Roche Diagnostics, and the KRYPTOR system from Brahms Diagnostics. We evaluated the analytical performance of the four systems and compared measurements of CA 19-9 values, which covered the whole analytical range.

RESULTS

The analytical performance and accuracy of the four systems were fairly good, but Passing-Bablok regression and mountain plots showed significant differences in CA 19-9 values measured with the four platforms.

CONCLUSIONS

Our data indicate that during tumor follow-up, the use of the same system is appropriate to avoid the risk of a variation due to the method rather than the disease. Moreover, whenever a change in analytical equipment is required, careful analysis of CA 19-9 results must be undertaken.

Immunoscintigraphy of colorectal carcinomas with radiolabeled monoclonal antibody fragments

BACKGROUND/AIMS

The aim was evaluation of the accuracy and clinical impact of the immunoscintigraphy for the detection of metastases and recurrences of colorectal carcinomas using two different radiolabeled antibody fragments.

METHODOLOGY

The study was performed in 5 patients with IMACIS 1 containing the cocktail of 111MBq 131I MoAb 19-9 F(ab')2 and MoAb anti-CEA F(ab')2 and 8 patients with INDIMACIS 19-9 containing 150MBq of 111In-labeled MoAb 19-9 F(ab')2.

RESULTS

With IMACIS 1, in all the patients, both tumor marker values were elevated. The number of TN was 3/5 and TP 2/5. From 2 TP, one had recurrence of the diseases with peritoneal carcinosis and one with liver metastases. In one patient, the results influenced the therapeutical management. With INDIMACIS 19-9, there were 2/8 TN, with borderline value of CEA and CA 19-9. TP were 6/8 (all with elevated tumor marker values, five of them many times; 3 with recurrences, 1 with recurrence and liver metastases and two with only liver metastases. In three patients, immunoscintigraphy influenced patient management.

CONCLUSIONS

With both radiopharmaceuticals, immunoscintigraphy significantly influenced the patient management or it was complementary. It would be performed in the detection of recurrence, assessment of viability and follow-up of the therapy.

Titration of serum p53 antibodies in patients with gastric cancer: a single-institute study of 40 patients

BACKGROUND

Alterations of the p53 tumor suppressor gene are the most commonly observed genetic abnormalities in many different types of human malignancies. The accumulation of mutant p53 often leads to the production of p53 antibody (p53-Ab) in the sera of patients with various cancers. To evaluate the clinical implications of serum p53-Abs in patients with gastric cancer, we compared p53-Abs with conventional tumor markers such as carcinoembryonic antigen (CEA) and carbohydrate antigen (CA)19-9.

METHODS

Serum samples were obtained preoperatively from 40 patients with histologically confirmed gastric adenocarcinoma, including 28 (70%) patients in stage Ia. The serum p53-Abs were assessed by enzyme-linked immunosorbent assay, using a new version of a highly specific, quantitative p53-Abs Kit (MESACUP Kit II).

RESULTS

p53-Abs were detected in 6 (15%) of 40 patients with gastric cancer, including 3 patients with early gastric cancer. Seven (17.5%) of the 40 patients were positive for CEA in serum. However, none of 7 patients with high CEA levels were positive for p53-Abs. No significant correlation of p53-Abs with patient age, sex, pathological parameters, tumor markers such as CEA and CA19-9, or poor survival (P = 0.116) was observed.

CONCLUSION

Although we employed the latest version of the p53-Abs Kit, the sensitivity of serum p53-Ab in gastric cancer patients was relatively low. No correlation was found between the presence of p53-Ab and the staging of cancer or survival. However, serum p53-Ab was detectable in patients with gastric cancer even in the early stages of disease. In addition, it may be independent of CEA and CA19-9.

Analysis of glycoproteins in human colon cancers, normal tissues and in human colon carcinoma cells reactive with monoclonal antibody NCL-19-9

The expression of sialyl Lewis(a) antigen, also known as Ca 19-9, in colon cancer, normal tissues and LS174T human colon carcinoma cells were studied. In colon adenocarcinoma and cell plasma membranes this antigen is expressed on various glycoproteins with different molecular weights ranging in size from over 200 kDa to about 100 kDa. In addition, there is very low expression in peritumoral tissues. In cytosol and culture medium this epitope is carried by a single complex-glycoprotein with a very high molecular weight resembling a mucin. In cells the rise in cAMP levels elevate the synthesis and release of the carbohydrate antigen 19-9; whereas the treatment with 1,9-dideoxyforskolin, a diterpene, which does not activate adenylate cyclase, has no effect on content of the antigen. These results suggest that cAMP is involved on the expression of glycoprotein-associated sialyl Lewis(a) antigen in LS174T cells.

Expression of inhibin/activin subunits, sialyl-lewis A (CA 19-9, sLea) and sialyl-Lewis X (sLex) carbohydrate antigens in a hydatidiform mole with persistent polymorphic trophoblastic hyperplasia

The persistence of polymorphic trophoblastic hyperplasia in a hydatidiform mole is an extremely rare condition. Its early diagnosis is essential since such cases can transform into invasive tumours.

MATERIALS AND METHODS

The paraffin-embedded biopsies were routinely stained with HE. Immunohistochemical staining reactions were performed with monoclonal antibodies against inhibin-alpha, inhibin-betaA and inhibin-betaB subunits. Additional immunohistochemical reaction was performed with, Sialyl-Lewis A and Sialyl-Lewis X and glycodelin.

RESULTS

Large villi and hydatidiform villi with ranging syncyctio- and cytotrophoblasts were seen. Intervillous proliferating trophoblasts showed cell- and nuclear polymorphy with invasion of the myometrium wall. The immunohistochemistry exhibited strong positivity for inhibin-alpha, inhibin-betaA and inhibin-betaB subunits in trophoblastic tissue, while the decidua was negative. Sialyl-Lewis A and Sialyl-Lewis X showed no or minimal focal immunohistochemical reaction.

CONCLUSION

A complete hydatidiform mole with hyperplasia and proliferation presents a high risk of developing a persistent (eventually metastatic) trophoblastic disorder and, in up to 15% of the cases, an invasive mole. In 2.5% of the cases it can transform into a choriocarcinoma. Since the inhibin/activin subunits reacted positively with trophoblastic tissue, they might be a useful diagnostic marker for hydatidiform mole with persistence of polymorphic trophoblastic hyperplasia.

Chemiluminescent immunosensor for CA19-9 based on antigen immobilization on a cross-linked chitosan membrane

A novel chemiluminescent immunosensor for carbohydrate antigen 19-9 (CA19-9) based on the immobilization of CA19-9 on the cross-linked chitosan membrane was developed. The different membranes were characterized by atomic force microscopy (AFM) and infrared spectrum, respectively. Based on a noncompetitive immunoassay format, this proposed chemiluminescent immunosensor enabled a low-cost, flexible and rapid determination for CA19-9 in combination with flow injection analysis (FIA). After an off-line incubation of the analyte CA19-9 with horseradish peroxidase (HRP)-labeled anti-CA19-9, the mixture was injected into the immunosensor, which led to the trapping of free HRP-labeled anti-CA19-9 by the immobilized antigen in the immunosensor. The trapped HRP-labeled antibody was detected by chemiluminescence due to its catalytic activity following the reaction of luminol and H2O2. Under optimal conditions, the decreased chemiluminescent signal of the immunosensor was proportional to the CA19-9 concentration in the range of 2.0-25 U/ml with a detection limit of 1.0 U/ml. The immunosensor showed an acceptable accuracy and good reproducibility. The results of 20 human serum samples detected by this method were in acceptable agreement with those obtained by immunoradiometric assay. The proposed immunosensor provided a new promising tool for practical clinical detection of the serum CA19-9 level.

Rapid purification of human ductal cells from human pancreatic fractions with surface antibody CA19-9

Generating human insulin-secreting cells for cell therapy of diabetes represents a highly competitive world challenge. Human ductal cells can give rise to islets in vivo and in vitro. The goal of this study was to devise a rapid sorting method to highly purify human ductal cells from pancreatic tissue using a pan-ductal membrane antibody carbohydrate antigen 19-9 (CA19-9). Human pancreatic sections confirmed antibody specificity. The human exocrine fraction (30% ductal cells) was sorted with magnetic bead technology or by FACS. Immunocytochemistry post-sorting determined ductal cell content. The manual magnetic bead technique resulted in 74%+/-2 (n = 4) CA19 positive cells. Whereas the automated AutoMACS technique (n = 5) yielded 92.6%+/-0.5 CA19-9 positive cells with only a minor beta cell contamination (0.2%+/-0.03); cell yield post-sorting was 12.9%+/-2.5 (1.69+/-0.41 x 10(6) cells) with 51.7%+6.5 (n = 5) viability post-sorting. The FACS (n = 6) resulted in 97.1%+/-0.82 CA19-9 positive cells, a cell yield of 25.5%+/-5.6 (5.03+/-1.0 x 10(6)), with 72.1%+/-6.1 viability post-sorting.

Serum carbohydrate antigen elevations in endometrial adenocarcinomas: characterization of DU-PAN-2 expression as a tumor marker

AIM

To characterize serum elevations of carbohydrate antigens; DU-PAN-2, CA19-9, sialyl Lewisx and CA125 in endometrial adenocarcinomas (EMACs), particularly focusing on the clarification of DU-PAN-2 expression profiles.

METHODS

Sixty-four resected EMACs of endometrioid type were used. The preoperative serum values of four markers were measured and comparatively analyzed regarding the relationship between histological grade and clinicopathological stage.

RESULTS

The overall ratios of positive cases were 26.2% for DU-PAN-2, 25.0% for CA19-9, 13.6% for sialyl Lewisx, and 35.5% for CA125. DU-PAN-2 decreased as the grading went up (G1: 410.3 +/- 243.8 to G3: 246.7 +/- 90.0 U/mL), however, the reverse was true with CA19-9 (G1: 123.9 +/- 147.4 to G3: 320.0 +/- 180.0 U/mL). Sialyl Lewisx showed a strong tendency towards high elevation in G1 (346.3 +/- 102.6 U/mL), compared to G3 (< 2.5 U/mL). CA125 increased markedly as the grading went up (G1: 43.5 +/- 6.3 to G3: 578.0 +/- 10.0 U/mL). During staging-up from I + II to III + IV, the positive ratios inclined in all four markers as follows: DU-PAN-2, 18.4-53.3%; CA19-9, 20.4-40.0%; sialyl Lewisx, 11.4-22.2%; CA125, 31.8-44.4%. Serum elevations and positive ratios were correlated for DU-PAN-2, CA19-9 and CA125, while the reverse relationship was found for sialyl Lewisx.

CONCLUSION

It is suggested that DU-PAN-2 tends to be produced more in well-differentiated components of EMACs than in poorly differentiated ones. Since approximately half the cases with EMAC were serologically positive for DU-PAN-2 in stage III + IV, the marker is believed to be of much use for monitoring the cases with an extrauterine extent.

[An early diagnosis of colorectal cancer]

Colorectal cancer is still a huge challenge for modern oncology due to a number of patients. The malignant disease is associated with industrial countries and mostly occurs in Europe and United States. Despite screening programs there are a constant number of 30% patients who have advanced colorectal cancer that is clinically relevant. On the other hand, a body of evidence is accumulating on the molecular mechanisms that play a pivotal role in development of sporadic and hereditary kind of colorectal cancers. In this review we presented molecular mechanisms involved in development of colorectal cancer. Moreover, we described the results of screening programs used to detect an early stage of colorectal cancer and modern molecular techniques useful at the time of detection micrometastatic disease involving lymph nodes and bone marrow.

Are serum and biliary carcinoembryonic antigen and carbohydrate antigen19-9 determinations reliable for differentiation between benign and malignant biliary disease?

BACKGROUND/AIMS

The value of serum tumor markers carbohydrate antigen 19-9 (CA19-9) and carcinoembryonic antigen (CEA) in the differential diagnosis of obstructive biliary disease is dubious. We aimed to define their usefulness prospectively.

METHODS

Thirty-seven consecutive patients (12 female, 25 male, median age: 54, range: 19-83 years) who were referred for endoscopic retrograde cholanugiopancreatography (ERCP) or percutaneous transhepatic cholangiography (PTC) examination for obstructive jaundice were included (all with dilatation of biliary tree in ultrasonography or computerised tomography). Bile was obtained through the nasobiliary or external drainage catheter, placed with ERCP or PTC, respectively. Serum samples were taken from all patients at the time of acquisition of bile. Serum and bile samples were stored at -50 oC until they were tested. CA19-9 and CEA levels were measured with chemiluminescent enzyme immunoassay methods in serum and bile samples by using immulite GI-MA and CEA commercial kits, respectively (DPC(r), Los Angeles).

RESULTS

In 22 patients with malignant disease, serum CEA levels were 38.6+/-115.8 ng/ml and CA19-9 were 386.9+/-409.7 U/ml, while in 15 patients with benign disease the serum CEA levels were 1.8+/-1.6 ng/ml and CA19-9 were 128.9+/-302.2 U/ml. The difference for both values was significant (p<0.05). In malignant disease bile CEA and CA19-9 levels were 160.8+/-457.8 ng/ml, 14000.9+/-19798 U/ml respectively, while in benign disease the corresponding levels were 21.08+/-48.6 ng/ml for CEA and 14818.9+/-24665.7 U/ml for CA19-9. The differences were not significant in this case (p>0.05).

CONCLUSION

It was concluded that serum CA19-9 levels are increased both in malignant and benign obstructive biliary diseases, albeit more significantly in the former. However, increase in serum CEA is mostly restricted to malignant diseases. Measurement of these markers in bile is of no value.

[CEA, CA-19-9 and il-8, sTNFRII and sil-2R in persons at high risk of colorectal cancer]

The aim of the study was to determine whether elevated concentrations of CEA, CA19-9, IL-8, sTNFRII and sIL-2R occur in persons at high risk of colorectal cancer. A group of 37 persons at high risk of colorectal cancer and 40 healthy subjects (control group) were included into this study. In both groups IL-8, sTNFRII and sIL-2R concentrations were measured by ELISA method (R&D Systems Minneapolis, USA). In the group of persons at high risk of colorectal cancer CEA and CA19-9 concentrations were determined using MEIA kits (Abbott Laboratories, USA). Using the 95th percentiles of the distribution in the control group the upper normal limits of IL-8, sTN-FRII and sIL-2R values were calculated. The cut-off value for CEA was 3 ng/ml and that for CA 19-9 was 37 U/ml. The incidence of elevated concentrations of the studied factors and concentrations of CEA and CA19-9 was compared. The association was assessed of elevated concentrations of the studied factors and CEA and CA19-9 with the results of histological examination of pathological changes in the colon and rectum. In the group of persons at high risk of colorectal cancer only CEA concentration was elevated in 2.7%. The percentages of persons with elevated concentrations of IL-8, sIL-2R and sTNFRII were 29.7, 8.1 and 18.9%, respectively. The percentage of persons with elevated concentrations of IL-8 and sTNFRII was higher in comparison with the percentage of persons with elevated concentrations of CEA and CA19-9 (p < 0.05). Pathological lesions in the colon and rectum were detected in 16 persons (43.2%). High-grade dysplasia was detected in 11 cases. Elevated concentration of IL-8 always accompanied high-grade dysplasia in ulcerative colitis. The concentrations of IL-8 were significantly higher in high-grade dysplasia (23.7 pg/ml, SD +/- 7.53) than in cases of its absence (18.9 pg/ml, SD +/- 3.53) (p < 0.05). The obtained results of preliminary studies with IL-8 in persons at high risk of colorectal cancer require a confirmation in population studies.

[Cystadenoma of the liver with high levels of ACE and CA 19-9 in the cyst]

The development of a cystadenocarcinoma from previously benign cystadenoma is controversial. Neither clinical nor biological factors have been described to explain this transformation. High levels of serum and cystic CEA and CA 19-9 seem to help in the diagnosis of cystadenoma but not cystadenocarcinoma. Definitive histological evaluation is the only means to discriminate malignant from benign cysts. We report a case of cystadenoma of the liver with very high cystic levels and normal serum levels of CEA and CA 19-9.

Comparison of different immunoassays for CA 19-9

We compared six routinely employed immunoassay kits: Architect i2000 and AxSYM, Abbott Laboratories; Elecsys 2010, Roche Diagnostics; ELSA, CIS-BioInternational; Immulite 1, Diagnostic Products Corporation; and IRMA-mat, Byk-Sangtec Diagnostica. Using all analytical systems, we measured identical groups of clinical samples completed with selected control samples. The repeatability of measurements (coefficient of variation) ranged from 2.1% (Elecsys 2010) to 6.7% (ELSA). The parameters of Passing-Bablok regression show significant systematic differences among analytical systems. Data from a Bland-Altman diagram suggest that these differences project onto other, still more significant individual differences among individual samples. Though the cut-off values differ between various systems, no similar clinical efficacy appears to be attained. The behavior of individual systems is quite different for identical control materials and does not necessarily duplicate the calibration for biological samples. The results of determining CA 19-9 cannot be extrapolated from one analytical technique to another, even in cases where the same monoclonal antibody is used. Standardization of CA 19-9 measurement systems is necessary to allow use of the results for the purposes of evidence-based medicine.

[The beta-hCG subunit, CA 125 and CA 19-9 antigen in the women with non-trophoblastic malignancy of genital tract]

OBJECTIVES

The aim of this study was preoperative estimation of serum level glicoprotein--CA 125, CA 19-9 and beta-hCG in ovarian tumors and comparison obtained values in groups divided according to postoperative pathologic examination.

MATERIALS AND METHODS

In every patients with ovarian tumors before surgery the level above mentioned antigens was evaluated and compared in following groups: malignant, non-malignant and controls. In control group cut-off values was estimated.

RESULTS

The levels of all investigated glycoproteins were significantly higher in malignant group comparing to benign and controls. The test differentiating non-malignant from malignant tumors was accepted as positive if at least one from markers level was elevated. Specificity of the test was 70%, sensitivity--94%, positive prognostic value--74%, negative prognostic value--94%. In the selected subgroups from non-malignant tumors the serum level of all glycoproteins was surprisingly high.

CONCLUSIONS

Preoperative estimation of CA 125, CA 19-9 and beta-hCG subunit in ovarian tumors permits--at negative result--with probability 93% to qualify tumor as non-malignant and sensitivity of test is 94%.

Summary report on the ISOBM TD-6 workshop: analysis of 20 monoclonal antibodies against Sialyl Lewisa and related antigens. Montreux, Switzerland, September 19-24, 1997

The ISOBM TD-6 Workshop is the first international workshop on monoclonal antibodies against the Sialyl Lewisa (SLea) antigen. Eight research groups participated in a blind study to characterize the epitope binding, relative affinity and performance in immunoradiometric assays, of a panel of 20 monoclonal antibodies. The antibodies were tested against a diverse panel of neoglycoconjugates, purified antigens and human serum pools from gastrointestinal malignancies. Epitope specificities were determined for the majority of antibodies in the panel. Cross-reactivity with related saccharide structures was noted in several antibodies. Overall, the results of the TD-6 Workshop show further development of SLea immunoassays may yield yet more specific assays for the detection and management of gastrointestinal and other malignancies.

Increase in the immunostimulatory effect of dendritic cells by pulsing with serum derived from pancreatic and colorectal cancer patients

Both we and others have observed a relative resistance of solid tumor cells to immunological effector cells in vitro, which may be one reason for the clinical phenomenon of resistance of patients with pancreatic carcinoma or other solid tumors to immunological therapeutic approaches. Dendritic cells (DC) are professional antigen-presenting cells which can process and present tumor-associated antigens such as CA 19-9. Here we tested DC pulsed with serum containing CA 19-9 for their capacity to stimulate immunological effector cells against pancreatic carcinoma cells. Coculture of immunological effector cells with DC led to a significant increase in cytotoxic activity as measured by a lactic dehydrogenase release assay. Most interestingly, cytotoxic activity against tumor cells was further increased using DC pulsed with patient-derived CA 19-9 containing serum. Similar results have been obtained using either autologous or allogeneic serum from patients with pancreas carcinoma. The effect of serum on the cytotoxicity of effector cells increased in a dose-dependent manner. Interestingly, heat inactivation led to a significant loss of immunostimulatory capacity of the serum. Cytotoxicity was partially inhibited by using an antibody directed against CA 19-9 on the surface of the target cells. Best results were obtained when adding CA 19-9 protein to CA 19-9 containing serum for pulsing of DC. In conclusion, DC pulsed with CA 19-9 containing serum increased the cytotoxic activity of immunological effector cells against pancreatic cancer cells. DC pulsed with CA 19-9 containing serum with or without additional exogenous CA 19-9 protein may have an impact on immunotherapeutic protocols for patients with CA 19-9 secreting tumors.

[The beta-hCG subunit, CA 125 and CA 19-9 antigen in the women with non-trophoblastic malignancy of genital tract. Endometrial cancer]

OBJECTIVES

There are few conflicting reports in regards of markers appearing in the patients with endometrial cancer. The aim of this study was to evaluate the serum levels: CA 125 antigen, CA 19-9 antigen and beta-hCG subunit in this group of patients and comparing obtained results with normal controls.

MATERIALS AND METHODS

In both groups--with endometrial cancer (n = 43)- and controls-(n = 214)--CA125 antigen, CA 19-9 antigen and beta-hCG subunit the serum level were determined two = site of immunometric method. The differences of the means, correlations, specificity, sensitivity, positive predictive value, negative predictive value and efficiency were calculated.

RESULTS

The women with endometrial cancer exhibited the significantly higher level of all antigens. The positive correlation between CA 125 serum level and staging and grading and between beta-hCG subunit and endometrial cancer staging was found. The positive test had: specificity--62%, sensitivity--93%, positive predictive value--66%, negative predictive value--92% and efficiency--92.5%.

CONCLUSIONS

In the women with endometrial cancer appears non-specific antigens characteristic for the müllerian duct derivatives tissue, exhibiting Lewis blood group antigen and involving in membrane cell structures in normal and cancer cells. The level of these antigens correlates with grading and staging of the neoplasms.

Increase of the immunostimulatory effect of dendritic cells by pulsing with CA 19-9 protein

Previously, a relative resistance of solid tumor cells to immunologic effector cells was shown in vitro. This resistance could be one reason for the clinical phenomenon of resistance of patients with colon carcinoma or other solid tumors to immunologic therapeutic approaches. In this study, dendritic cells (DCs) pulsed with CA 19-9 protein were tested for their immunostimulatory capacity of immunologic effector cells against cells derived from colon and pancreatic carcinoma. Dendritic cell cultures coexpressed CMRF-44 and CD1a, markers typical of DCs, in 31.5% +/- 5.3% after 13 days of culture. Coculture of NK-like T lymphocytes with DCs led to a significant increase in cytotoxic activity, as measured using a lactate dehydrogenase release assay. Cytotoxic activity could be further increased using DCs pulsed with CA 19-9 protein. The effect of CA 19-9 on increasing the cytotoxic effect of NK-like T lymphocytes was dose dependent. Similarly, cocultivation of DCs with NK-like T cells derived from patients with metastatic pancreatic cancer and elevated CA 19-9 serum levels led to a significant increase in cytotoxic activity. In conclusion, DCs pulsed with CA 19-9 protein can increase the cytotoxic activity of immunologic effector cells against colon carcinoma and pancreatic cancer cells. Dendritic cells pulsed with CA 19-9 protein may have an important effect on immunotherapeutic protocols for patients with cancer.

CA 19-9 monosialoganglioside content of human colorectal tumor cells correlates with tumor cell-induced platelet aggregation

BACKGROUND

Gangliosides are involved in tumor cell-induced platelet aggregation (TCIPA). CA 19-9 is a monosialoganglioside detected in colon carcinoma cells. Therefore, this study was designed to evaluate whether there was any correlation between the CA 19-9 monosialoganglioside content and TCIPA.

MATERIALS AND METHODS

The CA 19-9 content was determined on gangliosidic extracts of human colorectal tumor cells (GEO, WiDr, DLD-1, MIP) in comparison with the degree of TCIPA.

RESULTS

CA 19-9 was detected in all cell lines, except MIP. The mean CA 19-9 content was 10.2, 30.2 and 82.6 U/microgram of sialic acid for GEO, DLD-1 and WiDr, respectively. CA 19-9 content directly correlated with TCIPA (p < 0.0001). Furthermore, incorporation of exogenous gangliosides in GEO cells resulted in an increase of CA 19-9 content, paralleled by a concomitant increase of TCIPA.

CONCLUSIONS

The CA 19-9 monosialoganglioside may be involved in platelet/tumor cell interactions, thus playing an important role in the haematogenous metastases of colorectal cancer.

Detection of large molecular weight cytokeratin 8 as carrier protein of CA19-9 in non-small-cell lung cancer cell lines

It has been reported that cytokeratin 8 (CK8) is expressed in all non-small-cell lung cancers (NSCLC). We hypothesized that antigenic changes of CK8 may occur in some NSCLC cell lines. To prove this, Western immunoblot analysis using anti-human CK8 monoclonal antibodies as well as immunohistological staining of CK8 were performed in NSCLC cell lines. As a result, CK8 which had a higher molecular weight than recombinant CK8 was demonstrated in two of eight NSCLC cell lines. In addition, this CK8 contained antigenic epitopes of CA19-9. This CK8 with higher molecular weight, may have played a role in the process of invasion or metastasis of NSCLC.

[Extraordinary high elevation of serum CA19-9 levels in an apparently healthy subject]

We studied the woman presenting extraordinarily high serum CA19-9 levels who did not have any disease that was known to result in elevation of the serum CA19-9 level. Her CA19-9 values in sera obtained by 16 determinations with the enzyme immunoassay (EIA) over a period of 7 years were from 820 U/ml to 1,310 U/ml (median 1,015 U/ml). The correlation was good between serum CA19-9 levels in this subject with the EIA and radio immunoassay (RIA). The molecular weight of CA19-9 was determined by high-performance liquid chromatography (TSK gel G4000 SWXL column). While the molecular weights of CA19-9 in each patient with pancreatic cancer, cholangioma, cholecystitis or pancreatitis that were used as controls, were greater than 1,000 kDa, the CA19-9 of this subject had the molecular weight of approximately 550 kDa. To further determine whether human immunoglobulin was involved in the elevation of CA19-9 in the serum of this subject, we investigated the effect of adding rabbit anti-human IgM, IgG and IgA sera to the serum of this subject, CA19-9 values were unaffected by these antisera. Thus, the data obtained from the absorption study indicated that an anti-idiotypic antibody against the anti-CA19-9 antibody is unlikely to be responsible for an elevation of CA19-9 in the serum of this subject.

Immunoregulation in pancreatic cancer patients

Metastatic pancreatic cancer is one of the most aggressive cancer known in man yet specific antitumor immunity has been demonstrated in lymph nodes draining the sites of pancreatic tumors. Despite this immunity, pancreatic cancer patients suffer a quick demise. To further define tumor immunity in patients with metastatic pancreatic cancer, we sought to characterize helper T cell subsets, serum cytokines, cellular cytotoxicity that is both T-cell and non-T cell mediated, as well as known tumor-derived immunosuppressive products that may be present in their peripheral blood. Significantly heightened levels of interleukin 2 (IL-2), a Th1 cytokine, were found in patients before treatment with chemotherapy while serum IL-10, a Th2 cytokine, were at significantly lower levels than observed in normal donors tested between their fifth and seventh decades of life. IL-10 levels increased progressively with age as a serum-bound protein in normal, healthy donors tested between the ages of 24 through 61. An age associated progression of increased IL-10 levels was not observed in pancreatic cancer patients. Few patients had detectable serum levels of soluble fas ligand but approximately half had elevated levels of a tumor marker, detected with the CA-15.3 assay, known as soluble MUCIN 1 (MUC1). Cell mediated cytotoxicity including T-cell mediated killing of pancreatic tumor cell lines was detected in many patients. These data suggest that pancreatic cancer patients have activated type 1 helper T cells that can support development of cell-mediated immunity, and that their sera contain lowered levels of the "anti-inflammatory" type 2 cytokine, IL-10.

[Carbohydrate antigens CA 19-9, CA 242, CA 50 in liver diseases]

Serum concentrations of CA 19-9, CA 242, and CA 50 were determined in patients with hepatitis and liver cirrhosis without cholestasis. The study included 63 patients with chronic persistent hepatitis (group A), chronic active hepatitis (group B), and liver cirrhosis (group C). The control group (K) consisted of 82 patients with: peptic ulcer, colorectal polypi or diverticulosis of the colon. CA 19-9 level normal in the majority of patients with liver diseases, however, it was found to be increased in 4 (23%) of patients with liver cirrhosis. There was no statistically significant difference in the frequency of increased level of CA 19-9 between liver diseases and the control group. The rate of elevated serum level of CA 242 in patients with liver diseases and in control group was similar respectively 12%; 8.5%). The elevated CA 50 levels were most frequently found in patients with liver pathology (50% in liver cirrhosis and chronic active hepatitis; 36% in chronic persistent hepatitis).

CONCLUSION

The elevation of CA 50 serum level occurs very often in liver diseases, even when they are going without cholestasis. Thus, the antigen is not useful for differentiating between benign and cancer diseases of gastrointestinal tract. Antigen CA 50 is to be taken into account only after exclusion of the pathology of liver, especially cirrhosis. Other investigated antigens: CA 19-9 and CA 242 are influenced by liver diseases to a minor and neglectable extent. Antigen CA 19-9 is the marker of choice in gastrointestinal cancers.

[Gastrointestinal cancer antigen and immunoglobulins G, A, M in patients with head cancer]

The authors present the results of examinations of immunoglobulins A, G, M serum concentrations and of a sensitivity of test of biochemical tumor marker (Ca 19-9) in a group of 35 patients with head malignant tumors. There was a statistically significant increase of immunoglobulins IgA, IgG and decrease of immunoglobulin IgM. We observed statistical correlation between serum concentrations of IgA, IgG and serum concentrations of IgA, IgM. The sensitivity of Ca 19-9 was 23% in the preliminary study. The values of Ca 19-9 changed in monitoring of tumors to 26%. There was a statistically significant correlation between sensitivity of Ca 19-9 and serum concentration of IgM. We did not observe any statistical correlation between Ca 19-9 and the age of patients.

[Radioimmunoscintigraphy of colorectal cancer using the anti-CEA monoclonal antibody BW 431/26. Final results]

The anti-carcinoembryonic antigen (CEA) antibody, BW 431/26 (Scintimun CEA, Behringwerke, Marburg, Germany ) labeled with technetium pertechnectate (99mTc), is an intact immunoglobulin G1, monoclonal antibody that has been used to image colorectal cancer. Planar and SPECT images of chest, abdomen and pelvis were performed at 10 minutes, 4-6 and 18-24 hours after the intravenous antibody injection. 44 patients were studied and the pathological antibody concentration localization by radioimmunoimaging (RI) were correlated with surgical, clinical and other imaging modality findings to validate the RI. The RI was positive in 29 patients and negative in the other 15 patients. The CEA and CA 19.9 were elevated in the serum of some patients with primary tumors or recurrence. The HAMA were determined in all the patients before and after the RI.

Altered expression of sialylated carbohydrate antigens in HT29 colonic carcinoma cells

To determine whether cell growth conditions impacted carbohydrate expression, HT29 cells were gradually transferred from a conventional glucose-containing media to a glucose-free galactose containing media. Indirect immunofluorescence on acetone fixed cells showed increased expression of sialyl Lewis A antigen (CA19-9), sialyl Lewis C (DUPAN2) and Tn/sialyl-Tn on the surface of HT29 cells grown in the glucose-free galactose containing media compared to those grown in the glucose containing media. Sialyltransferases responsible for the synthesis for these sialylated epitopes were Increased in the galactose-fed HT29 cells. Media overlying the cells was subjected to isopycnic ultracentrifugation in cesium chloride and the fractions derived from both glucose and galactose media with equivalent buoyant densities of 1.56 g/L, which are predicted to contain mucin glycoforms, were further separated by HPLC using a Mono-Q anion exchange column. The chromatograph of eluent from the sample derived from the cells growing in the galactose containing media showed an increased peak that reacted with the anti-sialyl Lewis A antibody, CA19-9. These results show that alteration of in vitro culture conditions may cause HT29 colonic carcinoma cells to alter the expression of sialylated carbohydrates.

Increased serum CA 19-9 antibodies in Sjögren's syndrome

A 67-year-old woman with a history of thyroiditis presented with recent intermittent epigastric pain and nausea. Hyperamylasaemia, oedema of the pancreas, and high serum levels of lipase and CA 19-9 were found. Xerostomia and dry eyes developed later, accompanied by an abnormal Schirmer's test. The diagnosis of Sjögren's syndrome was confirmed by increased anti-Ro and anti-La antibodies and the histological findings of parotid gland biopsy. Two additional cases of Sjögren's syndrome with elevated serum CA 19-9 are also described. These observations of elevated serum lipase and serum CA 19-9 in Sjögren's syndrome without evidence of malignancy may reflect pancreatic involvement in this disorder.

[Prognostic value of tumor markers in intestinal cancer]

CEA, CA 19-9, APP tumor markers are highly specific tests for the gut malignant tumor spreading estimation. CEA application was proposed to estimate the operative intervention radicality and the adjuvant therapy efficacy in a colonic cancer patients.

[The value of gastrointestinal antigens in the monitoring of patients with malignant head neoplasms]

The authors present the results of examinations of test on the sensitivity of biochemical tumor marker (Ca 19-9) in a group of 35 patients with head malignant tumors. The sensitivity (SE) of Ca 19-9 was 22.9% in preliminary study. The values of Ca 19-9 changed from 22.9% to 25.9% in monitoring of tumors. Positive predictive value (PV+) and specify (SP) were 100% in preliminary study and in monitoring. Negative predictive value (PV-) was 50.9% in preliminary study and 51.6% in monitoring. In 25 patients we observed changes in examined parameters: SE--35%, SP--100%, PV(+)--100%, PV(-)--42.1% in monitoring. Our study indicates that serum levels of Ca 19-9 were higher in patients with head tumors than in control group. The surgical treatment of tumors didn't change the values of Ca 19-9.

Utility of the antibodies CA 19-9, HBME-1, and thrombomodulin in the diagnosis of malignant mesothelioma and adenocarcinoma in cytology

BACKGROUND

The distinction between malignant mesothelioma (MM) and adenocarcinoma (ACA) in cytologic specimens frequently is difficult, often requiring immunocytochemistry to support the diagnosis. Recent reports have proposed the utilization of antibodies to mesothelial cell clone HBME-1 and thrombomodulin (TM), because they are immunoreactive in MM and less commonly reactive in ACA. Immunoreactivity for the monoclonal antibody CA 19-9 has been observed in many ACAs and reportedly is absent in MM.

METHODS

In this study, immunostaining was performed on formalin fixed, paraffin embedded cell blocks from effusions or fine-needle aspirations using the avidin-biotin-peroxidase method. Thirty-eight MMs and 49 ACAs were tested using antibodies to CA 19-9, HBME-1, and TM.

RESULTS

Anti-CA 19-9 stained only 1 of the 37 cases of MM tested (3%), but stained 24 of the 49 cases of ACA (49%). Anti-HBME-1 stained 34 of 38 cases of MM (89%), and 28 of 43 cases of ACA tested (65%). Anti-TM stained 24 of 36 cases of MM (67%), and 21 of 40 cases of ACA tested (53%).

CONCLUSIONS

CA 19-9 has utility as part of an immunocytochemical panel for distinguishing ACA from MM, because a positive staining reaction would make the diagnosis of MM unlikely. Although HBME-1 and TM can identify MM positively, each frequently is detected in ACA, thus limiting the utility of these antibodies in cytologic specimens.

[Comparative study of the role of CA 19-9, CA 72-4 and CEA tumor antigens in the diagnosis of pancreatic cancer and other gastrointestinal malignant diseases]

The diagnostic value of CA 19-9, CA 72-4 and CEA was evaluated in 291 patients (including 39 with pancreatic cancer, 32 with gastric cancer, 36 with colorectal cancer and 40 with chronic pancreatitis). These markers were determined in the serum by chemiluminescence immunoassay (CA 72-4) or microparticle enzyme immunoassay (CA 19-9 and CEA) methods. In serodiagnostic evaluations relating to pancreatic cancer, CA 19-9 proved superior to CA 72-4 and CEA (sensitivity: 79.5 vs. 56.5 and 62.5%; specificity: 84.1 vs. 77.9 and 77.2%; diagnostic accuracy: 85.9 vs. 75.8 and 75.7%, respectively). For gastric carcinoma, CA 72-4 appeared the most sensitive: 53.1% of all patients were identified with a specificity of 78.9% and a diagnostic accuracy of 75.4%. In the diagnosis; of colorectal cancer, CEA exhibited the highest sensitivity (63.9%) and diagnostic accuracy (76.2%). Elevated CA 19-9 levels were obtained in only 7.7% of patients with chronic pancreatitis. Tumor marker determination is useful in the diagnosis of gastrointestinal malignancies: the marker of choice in pancreatic cancer is CA 19-9, in gastric cancer it is CA 72-4 and in colorectal cancer it is CEA. CA 19-9 is effective in discriminating between pancreatic cancer and chronic pancreatitis.

Specific activation of resting T cells against CA19-9+ tumor cells by an anti-CD3/CA19-9 bispecific antibody in combination with a costimulatory anti-CD28 antibody

Specific activation of resting lymphocytes for tumor targeting can be achieved by bispecific monoclonal antibodies (bi-mAb) with specificity for tumor antigens and T-cell-activating antigens, respectively, in combination with a costimulatory anti-CD28 antibody. We describe the generation and function of a bi-mAb with specificity for CD3 and for the tumor antigen CA19-9. The bi-mAb OKT3/NSI19-9 was generated by somatic fusion of two hybridoma lines secreting antibodies against CA19-9 and CD3, respectively. A hybrid/hybridoma was established, and its bi-mAb was characterized. In combination with a costimulatory anti-CD28 mAb resting peripheral lymphocytes could be activated specifically with T-cell proliferation and secretion of high amounts of interferon-gamma. On specific T-cell activation, bi-mAb OKT3/NSI19-9 could also redirect the cytotoxic effects of these T cells toward CA19-9+ tumor cells in vitro. Our results indicate that specific activation of resting T cells with bi-mAb OKT3/NSI19-9 in combination with an anti-CD28 mAb can activate resting T cells specifically and leads to antigen-dependent bi-mAb-mediated cytotoxicity against CA19-9+ target cells. This approach may offer new perspectives for the specific immunotherapy of CA19-9+ tumors.

A multicentre evaluation of the CA 15-3 assay, CA 19-9 assay and CA 125 II assay on the Bayer Immuno 1 System

The analytical performance of the tumour markers CA 15-3 assay, CA 19-9 assay and Ca 125 II assay on the Bayer Immuno I System was studied according to a revised version of the ECCLS guidelines (Haeckel R. In: Evaluation methods in laboratory medicine, Weinheim, VCH Verlag 1993:47-69) in a multicentre evaluation involving five laboratories. Determination of the 3 analytes generated more than 6000 data. On the Bayer Immuno I System, the imprecisions of the CA 15-3 assay, CA 19-9 assay and CA 125 II assay were better than those found for comparison methods. The median recovery over all five laboratories of system assigned values in control sera was within the 1-s range for the three tumour marker assays. No deviation of linearity could be detected experimentally for all assays. Results for patients' samples showed acceptable agreement between the Bayer Immuno 1 system and several different comparison methods in most cases. One exception was the CA 15-3 assay in comparison with the MCA assay from Roche Diagnostic Systems, where the large difference in values is due to the use of different antibodies and calibrators in the two assays. No carry-over effects could be detected. The selective Bayer Immuno 1 system is fully automated; its practicability was rated as high.

Specific activation of resting T cells against tumour cells by bispecific antibodies and CD28-mediated costimulation is accompanied by Th1 differentiation and recruitment of MHC-independent cytotoxicity

Specific activation of resting lymphocytes for tumour targeting can be achieved by bispecific monoclonal antibodies (bi-MoAbs) with specificity for tumour antigens and T cell-activating antigens in combination with a costimulatory anti-CD28 antibody. In this study we focus on the immunomodulatory function of an anti-CD3/CA19-9 bi-MoAb in combination with a costimulatory anti-CD28 antibody which may result not only in antigen-specific, T cell-mediated tumour cell lysis but also in recruitment of other cellular effector functions. In combination with costimulatory anti-CD28 antibodies, resting peripheral lymphocytes could be activated specifically to secrete high amounts of Th1 cytokines (IL-2, interferon-gamma (IFN-gamma)) characterizing a cellular immune response. In contrast, no IL-4 and only low amounts of IL-10 could be detected. Furthermore, bi-MoAb-mediated CA19-9-specific activation of T cells was accompanied by recruitment of MHC- and CA19-9-independent cytotoxicity, as was determined by lysis of different CA19-9-cell lines. This MHC-independent cytotxicity was mediated at least in part by activated natural killer (NK) cells, as depletion of CD16+ NK cells resulted in substantial decrease of cytotoxicity against CA19-9- targets. Our results indicate that specific activation of resting T cells with CD3-associated bi-MoAbs in combination with an anti-CD28 antibody leads to a Th1 differentiation pathway and is accompanied by recruitment of MHC-independent lymphokine-activated killer (LAK) cell cytotoxicity which can possibly be directed against a heterogeneous tumour.

Serum and cystic fluid CA 19-9 determinations as a diagnostic help in liver cysts of uncertain nature

The distinction between hepatobiliary cystadenoma or cystadenocarcinoma and simple hepatic cyst complicated by intracystic hemorrhage may prove difficult to determine on the sole basis of clinical and radiological features because of the presence of intracystic structures and septations well-demonstrated by ultrasound examination in both situations. We investigated four patients with various types of hepatic cysts, in whom diagnostic difficulties led to further investigations. In this small group, CA 19-9 serum levels were abnormal only in the two patients with cystadenoma or cystadenocarcinoma. Cystic fluid CA 19-9 values were also five times higher in cystadenoma and cystadenocarcinoma than in other benign lesions. Our data thus suggest that the determination of serum and cyst fluid CA 19-9 may be of help in distinguishing between hemorrhagic simple cyst and cystadenoma or cystadenocarcinoma.

Genetic evidence for the Lewis enzyme, which synthesizes type-1 Lewis antigens in colon tissue, and intracellular localization of the enzyme

To determine whether the Lewis enzyme responsible for the Lewis blood type antigens on erythrocytes synthesizes the Lewis antigens on normal cells and cancer cells in colon tissue, we performed genotyping of the Lewis gene by the PCR-RFLP method and by immunohistochemical staining of Lewis antigens and the Lewis enzyme with specific monoclonal antibodies (mAbs) in colon tissues obtained from 100 colon cancer patients. Five of the 100 patients were identified as homozygotes for the mutant Lewis gene, i.e., the le/le genotype that cannot encode functional Lewis enzyme. The cells in both the normal and cancerous regions of colon tissue from these five le/le patients were completely devoid of staining with mAbs against Lewis antigens with the type 1 chain, i.e., Lewis a, Lewis b, and sialyl Lewis a. In contrast, the cells in cancerous regions of the colon tissue of the 95 patients with the Le/Le or Le/le genotype positively stained with all three mAbs, anti-Lewis a, anti-Lewis b, and anti-sialyl Lewis a. The cells in the cancerous regions of the colon tissue of the five le/le patients stained with DU-PAN-2 mAb, whose recognizing epitope is known to be sialyl Lewis c, a precursor structure of sialyl Lewis a. By immunohistochemical staining with FTA 1-16 mAb, which is directed at the human Lewis enzyme, we were able to demonstrate for the first time that the enzyme is localized in the Golgi area of the colon epithelial cells of patients with the Le/Le or Le/le genotype. No staining was observed in the Golgi area of the cells of the patients with the le/le genotype. From these results, we conclude that individuals with the Le/Le or Le/le genotype possess a functional Lewis enzyme synthesizing fucosylated type-1 Lewis antigens in the Golgi apparatus of the colon epithelial cells, but that individuals with the le/le genotype are devoid of the Lewis enzyme in the Golgi apparatus, resulting in an inability to synthesize Lewis antigens with the type-1 chain, and that it is inappropriate to use CA19-9, whose antigenic epitope is defined as sialyl Lewis a, as a tumor marker in patients with the le/le genotype.

[Lewis antigens in human colon carcinoma]

Aberrant glycosylation is a common phenomenon accompanying colon carcinoma progression. The changes observed include increased expression of Lewis blood group family antigens, particularly Lex, sialyl Lex and sialyl Lexa. Recently it was shown that these antigenic epitopes may play an important role in cell-cell homotypic as well as heterotypic adhesive interactions. This work presents a phenotypic characteristic of 11 human colon carcinoma cell lines of different degree of differentiation. Expression of potential ligands for endogenous cellular lectins: Lewis antigens, CEA and CD44v6 antigens was evaluated by cytofluorimetry. The aim of the work is to select adhesive and invasive colon carcinoma cells with specified cell surface antigen pattern, for studies on adhesive interactions with endothelial cells, occurring during early steps of metastasis.