Specificities and binding properties of 2 monoclonal antibodies against carcinoma cells of the human urinary bladder

Characterization of mouse monoclonal antibody B1.4 reactive with human invasive bladder cancer and some other malignant tumors but not with normal urinary epithelium

Immunohistochemical analysis by indirect immunoperoxidase staining demonstrated that monoclonal antibody (mAb) B1.4 derived from a mouse immunized with a bladder cancer cell line EJ-1 was reactive with a high proportion of high-grade and invasive bladder tumors, but not with the majority of low-grade and superficial bladder tumors, or normal urinary epithelium. Among 71 primary bladder tumors classified by pathological grading, positive stainings were observed in 1 of 34 tumors (3%) of grade 1, 8 of 20 tumors (40%) of grade 2 and 14 of 17 tumors (82%) of grade 3. When the tumors were classified by pathological staging, positive stainings were observed in only 8 of 54 (15%) superficial tumors of stages Ta and T1, but in 15 of 17 (88%) invasive tumors of stages T2 and T3. mAb B1.4 showed restricted positive stainings with normal tissues including renal glomerulus, vascular endothelium, squamous epithelium of esophagus, glandular epithelium of prostate, and epithelium of pancreatic acinar gland and minute duct, while positive stainings were observed in a range of tumor tissues other than bladder tumor. Mixed hemadsorption assays with a panel of cell cultures showed also that the antigen recognized by mAb B1.4 was expressed on a range of tumor cell lines. These findings suggest that the antigen recognized by mAb B1.4 may appear after malignant transformation, and be an indicator of malignant potential of bladder cancer.

Cell surface differentiation antigens of normal urothelium and bladder tumors

Bladder cancer ranks as the third most common malignancy among men and tenth among women. Superficial transitional cell carcinomas (stage Ta, Tis, and T1) account for approximately 70-80% of these tumors, while the remaining 20-30% are invasive (T2, T3, and T4). Approximately 70% of superficial tumors will have one or more recurrences, with 25% of these expressing a higher histologic grade and 10-15% subsequently developing invasive and/or metastatic disease. The detection and prediction of tumor recurrence and/or tumor progression is crucially important if timely and appropriate therapy is to be instituted. Conventional histopathologic evaluation usually provides definitive diagnosis upon which therapeutic planning is based. However, at present there are no more reliable morphologic indicator to identify which individuals will have recurrent disease or who will progress to invasive and/or metastatic cancer. Recent advances in tumor biology have identified markers that are good candidates for clinical applications in early tumor detection, as well as for the stratification of patients with like-appearing morphological lesions with different biological and clinical behavior. The ultimate goal is to develop predictive assays that would segregate patients with high probability of failures versus patients who would be cured by localized modes of therapy.

Monoclonal antibody Due ABC 3 directed against transitional cell carcinoma. I. Production, specificity analysis, and preliminary characterization of the antigen

The development of the hybridoma technology allows the identification of tumor associated antigens with monoclonal antibodies (mAbs). Employing this technology mAb Due ABC 3 was obtained by immunization of a BALB/c mouse with bladder tumor cell line SW 1710 and subsequent cell fusion of spleen cells with P3. X63.Ag8.653 mouse myeloma cells. MAb Due ABC 3, an IgM antibody, was found to recognize an antigen present in the membrane of tumor cells in 25 out of 28 (89%) transitional cell carcinoma specimens but rarely (three out of 25 specimens, 12%) on normal urothelial cells. Cross reactions were seen with proximal tubular epithelium of the kidney and seven out of 12 renal cell carcinomas examined. Furthermore, the antigen was expressed by granulocytes, some gastrointestinal epithelia, ovarian and breast carcinoma. The antigen recognized by mAb Due ABC 3 was stable to fixation with formaldehyde and paraffin emmbedding, different proteases, alkaline treatment and heat exposure up to 70C. Antigenicity was abandoned by incubation with periodate but not with neuraminidase treatment. The antigen could be extracted with chloroform/methanol suggesting the involvement of a glycolipid. Immuno-thin layer chromatography revealed a single lipid band reacting with mAb Due ABC 3 but not with anti-CD15, directed against the Lewis X antigen. Although not tumor-specific, mAbs directed against differentiation antigens may be of value for the investigation of cell transformations as well as for diagnostic use.

Immunohistochemical staining of CA 50 antigen in human bladder cancer. Relation to histologic grade, clinical stage, and prognosis

The immunohistochemical detection of tumor marker CA 50 was studied in bladder cancer of WHO grades I-III. The material consisted of tumors in 83 patients and the mean clinical follow-up time was thirteen years (range 9.6-22 years). The fraction of CA 50-positive cells (FPtot) in microscopic image was scored 0-100 percent. Also the maximally staining region was selected, and the fraction of CA 50-positive cells in this region was scored 0-100 percent (FPmax). The average staining intensity of CA 50-positive cells was scored from 0 to 3 in the whole section (ASItot) and in the maximally staining area (ASImax). The inverse relation between histologic grade, FPtot (p = 0.0001), and ASItot (p = 0.006) was statistically significant. FPtot (p = 0.039) and ASItot (p = 0.018) were also inversely related to clinical stage. Occurrence of metastasis during the follow-up was associated with low CA 50 positivity (FPtot, p = 0.003; ASItot, p = 0.002). The lower the staining intensity or the lower the fraction of CA 50-positive cells, the more aggressive was the tumor. In survival analysis, low FPtot (p = 0.002) and ASItot (p = 0.007) values were related to high risk of bladder cancer death. The results show that immunohistochemical staining of bladder tumor specimens with CA 50 can be used to predict bladder cancer aggressiveness and survival.

Monoclonal antibody against a tumor-associated sialoglycoprotein of superficial papillary bladder tumors and cervical condylomas

A mouse IgG1 monoclonal antibody (MAb), 19A211, defining a tumor-associated cell-surface antigen of superficial papillary bladder tumors, was generated by immunizing with fresh bladder tumor cells mice neonatally injected with normal human urothelial cells. The reactivity of the antibody with cell lines was examined by indirect immunofluorescence staining and was restricted to 3/14 bladder cancer lines and 3/31 cancer cell lines of non-bladder origin, including HeLa cervical cancer. No normal fibroblast, kidney cells, EBV-lymphocytes, erythrocytes or leukocytes expressed the antigen. Reactivity of MAb 19A211 was well preserved on tissue paraffin sections. Immunoperoxidase staining of normal adult or fetal tissues showed no reactivity except for a patchy or uniform staining of umbrella cells in 6/23 adult and 1/4 fetal urothelium samples. Positive and often heterogeneous staining was observed on 24/38 papillary superficial tumors (Ta) and 4/5 carcinoma in situ bladder lesions but on only 4/20 infiltrating tumors. It was also observed on 5/6 cervical condylomas and one bladder condyloma, but none of 6 penile or vulvar condylomas. All other tumors tested were negative. The antigenic determinant is present on a heterogeneous group of proteins with molecular weights ranging from 90 to 200 kDa. It is sensitive to periodate treatment and to neuraminidase but only partially sensitive to proteases. MAb 19A211 is different from other reported MAbs with similar reactivity to superficial bladder tumors and umbrella cells of normal urothelium. When tested in competition assays, several of these MAbs, but not 19A211, were found to react with Lewis X blood group determinant. Our results suggest that 19A211 may be useful for detection and stratification of bladder tumors.

Diagnostic and therapeutic utility of monoclonal antibodies in urologic oncology

Remarkable advances in the treatment of urologic malignancies have recently been made. Monoclonal antibodies selective for a variety of normal and malignant urologic tissues have been useful in defining normal antigens and tumor-associated antigens and have potential as diagnostic and immunotherapeutic agents. In renal cancer, monoclonal antibodies can define serum markers, radiolabel tumor xenografts, and assist in specific tissue diagnosis. Additionally, there is potential for these antibodies either alone or as conjugates to localize and kill tumors. Monoclonal antibodies to bladder cancer associated antigens are able to demonstrate differential antigen expression on superficial versus invasive tumors, to refine urinary cytologic diagnosis of bladder cancer, and to predict invasive recurrence of superficial cancer. Monoclonal antibodies have localized bladder tumor xenografts and can inhibit tumor growth when conjugated to radioisotopes or toxins. In prostate cancer monoclonal antibodies to prostate antigens are not usually tumor specific. Monoclonal antibodies to prostate antigen (PA) and prostatic acid phosphatase (PAP) are able to localize prostate cancer metastases. Chemotherapy-conjugated anti-PAP monoclonal antibodies have demonstrable inhibition on human prostate cancer xenografted tumor growth. Monoclonal antibodies have defined normal and tumor-associated antigens in urologic cancers and are expected to be useful in immunodiagnosis and cancer therapy in the near future.

A monoclonal antibody to human transitional cell carcinoma of the bladder: production and characterization

In order to detect bladder tumor specific antigens, monoclonal antibodies (MoAbs) to human transitional cell carcinoma of the bladder (TCCB) were obtained. Hybridomas were cloned after being prepared by cell fusion between mouse myeloma cell line X63Ag 8.653 and the spleen cells of BALB/c mice hyperimmune to the bladder cancer cells (grade 2) from a patient. Subsequently 12 MoAb-producing clones were obtained for the panel screening by enzyme immunoassay (EIA) and three MoAbs (no. 10, 11 and 14) were selected for reactivity to bladder cancer cells from patients, including normal epithelia. Finally No. 10 was selected as the most appropriate MoAb for this study and determined IgM with kappa-light chains by EIA. We accurately tested MoAb No. 10's reactivity with 71 malignant tumors by immunoperoxidase staining (IIP). No. 10 reacted to most TCCB cells (36/43), but did not react to any of the other tissues, including five normal epithelia, two brain tumors and three sarcomas. It was also shown by both IIP and immunofluorescent staining (IIF) that No. 10's reactivity was limited to the cancer cell membrane. These results suggest that the antigen recognized by MoAb No. 10 is one of the tumor-associated antigens and that some heterogeneity exists in its distribution.

A rapid method for detection of cellular proliferation using carboxyfluorescein. Assay of growth factors (IL-2, IL-1) and growth inhibiting antibodies

The uptake of carboxyfluorescein diacetate (CFDA) into live cells was used as the basis for a simple, rapid and fully automated micromethod for determination of cell growth. The aim of the investigation was to adapt the CFDA method for detection of cell growth factors from cell culture supernatants. Thus, the biological activities of the growth factors IL-2 or IL-1 could be detected and quantitated at the same level of sensitivity as with the conventional [3H]thymidine incorporation. Similarly, the method was well suited to assay inhibition of IL-2-dependent lymphocyte growth by the monoclonal antibody anti-Tac, binding to the human lymphocyte membrane receptor for IL-2. The CFDA method proved to be rapid, reliable and well suited for several applications involving limiting numbers of cells and biological reagents.

Isolation and characterization of two bladder carcinoma-associated antigens

By the use of mouse monoclonal antibodies we have earlier defined five distinct antigens associated with transitional cell carcinoma of the human urinary bladder (TCC). Two of these antigens have now been purified and partially characterized. For their purification from isolated tumor cell membranes, a rapid and efficient method of affinity chromatography was developed in which the coupling of monoclonal antibodies to protein A-Sepharose was fortified by treatment with glutaraldehyde. From these columns, 60-80% of the antigenic activity present in membrane lysates could be recovered by acid elution, corresponding to approximately 0.25-0.5 micrograms antigen protein per mg membrane protein added. The two isolated antigens are relatively hydrophobic membrane components not found in normal bladder tissue. The antigen defined by the monoclonal antibody S2C6 is confined to bladder carcinoma and B cells. It is a glycosylated, ConA-binding polypeptide with Mr 50 000 as established by SDS-PAGE. It is acidic with an IP of 3.2, heat stable up to 85 degrees C, stable at low pH (2.0) but sensitive to SDS. The antigen defined by the monoclonal antibody 7E9 is confined to bladder carcinoma but is also weakly expressed in some blood vessel endothelium. It consists of two main polypeptides of Mr 29,000 and 23,000 which do not bind to ConA. It has an IP of 7.4 and its antigenic activity is abolished by heating to 50 degrees C for 5 min. As the S2C6 antigen, it is stable at low pH but susceptible to SDS.