Cellular cytotoxicity in vitro in transitional cell carcinoma of the human urinary bladder: 51Cr-release assay

Enhancement of human spontaneous cell-mediated cytotoxicity by a monoclonal antibody against the large sialoglycoprotein (CD 43) on peripheral blood lymphocytes

A murine monoclonal antibody, MoAb B1B6 (IgG1 chi), which recognizes the large sialoglycoprotein (LSGP) on human peripheral blood lymphocytes (PBL) effectively enhanced the spontaneous cytotoxicity of these cells against the natural killer (NK)-sensitive target cells K562 and Molt-4. Whereas preincubation of the lymphocytes with MoAb B1B6 resulted in increased cytotoxicity, preincubation of the target cells had no effect, indicating that the MoAb amplified cytotoxicity at the effector cell level. Kinetic analysis of the data revealed no differences between the control and the MoAb-treated lymphocytes with regard to Vmax, usually considered to reflect the overall lytic potential of the cells. The slopes of the saturation curves, however, differed significantly for the two cell populations, indicating a substantial increment in the activity of the MoAb-treated cells. When studied at the single cell level and with K562 as targets, treatment of PBL with the MoAb resulted in the recruitment of new effector lymphocytes from the pool of non-binding cells. In contrast, when Molt-4 cells were employed as targets, no additional effector cells were recruited. These results indicate that the enhanced cytotoxicity induced by MoAb B1B6 is the result of either recruitment of new effector lymphocytes or of an increased recycling capacity of preexisting effector cells. Together with previous observations, these findings support the conclusion that LSGP belongs to the set of surface molecules which regulate human lymphocyte activation.

T lymphocytes displaying major histocompatibility complex-unrestricted cytotoxicity after activation by K46M, a mitogenic monoclonal antibody against leucoagglutinin-reactive human T lymphocyte surface components

Activation of human peripheral blood lymphocytes (PBL) with the mitogenic monoclonal antibody (MoAb) K46M, which recognizes 1-5% of PBL, resulted in the expansion of cells with cytolytic activity. Thus, after culture of the activated lymphocytes in medium containing interleukin 2 (IL-2), they lysed a variety of cultured cell lines. The majority of the activated lymphocytes reacted with MoAb to CD8, CD3, and to the T cell antigen receptor heterodimer (Ti) but not with antibodies to antigens expressed on natural killer (NK) cells. The cytotoxicity was not inhibited by MoAb to CD3 or Ti. However, the killing of K562, but not of other cell lines, was enhanced by three to four times in the presence of anti-Ti antibodies. Anti-CD3 or other control antibodies had no effect. Cold target inhibition experiments indicated that the cytolytic lymphocytes recognized closely related structures on the target cells. Phenotypically and functionally similar effector cells emerged after activation of PBL with the anti-CD3 MoAb OKT3. Taken together, the results indicate that activation of PBL with MoAb K46M induces cytotoxic cells that differ from classical NK cells but that resemble mature cytotoxic T lymphocytes (CTL). However, unlike CTL, cytotoxicity was not MHC-restricted and the conventional T-cell receptor complex (CD3/Ti) appeared not to be involved in target cell recognition and cytolysis.

Monoclonal antibodies for characterization of the heterogeneity of normal and malignant transitional cells

We present two monoclonal antibodies (mab), Mano 4/4 and 486 P3/12, directed against tumor-associated antigens of different subpopulations of transitional cell bladder carcinoma tumors. A detailed description is given concerning their reactivity patterns in an ELISA assay against different cell lines. Using immunohistochemical staining against normal bladder mucosa, mab Mano 4/4 reacts with distinct cells in the basal layer and mab 486 P 3/12 recognizes single cells in the superficial layer. Analysing different transitional-cell carcinomas, mab Mano 4/4 reacts with 17 of 20 and mab 486 P 3/12 with 17 of 19 bladder tumors. It is emphasized that both mabs may add new information in respect to a better characterization of the heterogeneity of bladder carcinoma. A biochemical characterization of the mabs and their corresponding antigens is given. Mab Mano 4/4 is directed against a 28 kD glycoprotein and mab 486 P 3/12 is reacting with a 200 kD glycoprotein belonging to the family of CEA-like proteins.

Monoclonal antibodies against human urinary bladder carcinomas: selectivity and utilization for gamma scintigraphy

Mouse monoclonal antibodies to human urinary bladder carcinoma cells have been examined by indirect membrane immunofluorescence using a panel of 27 human cell lines. Two of the monoclonal antibodies, 7E9 (IgG3) and S2C6 (IgGl), were found to distinguish between urinary bladder carcinoma cells and normal urothelium. The third monoclonal antibody, T24.06.5(IgGl), discriminated among cell lines of urothelial and non-urothelial origin but did not distinguish between urinary bladder carcinoma and normal urothelial cells. None of the of the antibodies was found to be strictly selective, and occasional cross-reactions with unrelated cell types were observed. The monoclonal antibody 7E9, showing the highest degree of selectivity, was further examined by an indirect immunoperoxidase technique on frozen tissue sections from 19 patients. The antibody reacted with all (7/7) bladder carcinomas examined and gave negative results with control normal bladder mucosa (0/8) and unrelated tumor tissue (0/4) sections. The 7E9 antibody was purified by protein A affinity chromatography, labeled with 131I and used for gamma-scintigraphy in nude mice xenografted with human urinary bladder carcinoma T24. The 7E9 antibody was capable of locating the T24 xenografts in nude mice; it localized preferentially in the T24 tissue compared to normal mouse tissues. The T24 xenografts could not be detected by gamma-scintigraphy with 131I-labeled monoclonal antibody against human mammary carcinoma cells and two other control antibodies. Likewise the 131I-labeled 7E9 antibody was not capable of locating human mammary carcinoma xenografts in nude mice.

Comparative studies of normal, 'spontaneously' transformed and malignant human urothelium cells in vitro

In numerous in vitro studies of cell-mediated cytotoxicity directed against transitional cell carcinomas (TCC) urothelial cells of normal origin have served as control material. In the present work, which includes 13 human bladder cell lines of non-malignant or malignant origin, a comparison was made of morphology, chromosomal mode, growth fraction and tumorigenicity in nude mice. Signs of apparently spontaneous transformation were seen in two cell lines of non-malignant origin. The possibilities for cross-contamination as an explanation of these signs of 'spontaneous' transformation are discussed. During these studies radiation-dependent cytotoxicity of disposable microtissue culture plates was revealed as another important source of error.

Lectins as probes for identification of tumor-associated antigens on urothelial and colonic carcinoma cell lines

In the search for tumor-associated antigens, seven lectins were used to investigate the cellular distribution of membrane-associated glycoproteins on a panel of human cells derived from tumor or normal tissues. Surface labelled lysates of the different cells were precipitated with the lectins and the precipitates were separated on SDS-PAGE. Comparison of the autoradiographic patterns revealed that a La-reactive 115K glycopeptide (gp 115) was present on transitional-cell carcinoma cells of the urinary bladder, on two spontaneously transformed urothelial cell lines and on a melanoma cell line. Gp 115 was absent from a non-transformed urothelial cell line, a squamous bladder carcinoma line and five unrelated cell lines of miscellaneous tissue origin. When precipitation was performed with a rabbit antiserum raised against the La-reactive components of a TCC cell line the same distribution of gp 115 was observed. From Helix pomatia hemagglutinin (HP) precipitates a 150K glycopolypeptide co-migrating with a previously described HP-reactive differentiation antigen associated with human T cells was present on one of the urothelial cell lines and on a colon carcinoma cell line. When different extracts depleted of ConA binding glycopeptides were compared, a group of three antigens (32K, 35K and 40K) were identified in the extracts of the colon carcinoma cell line, HT29. These antigens were shared by two other colon carcinoma cell lines but were absent from the unrelated cells of our panel. Furthermore, an extensively absorbed rabbit anti-HT29 serum specifically precipitated one of these antigens (35K) from the three colon cell lines.

A study of the immune response to the organ-specific neoantigen of human bladder cancer

The antitumor immune response of monocytes armed with cytophilic antitumor antibody to an organ-specific neoantigen of human bladder cancer was measured by the tube leukocyte adherence inhibition assay. Of 29 patients with Stage A bladder cancer, 27 had positive tests, whereas of 11 patients with Stage B, C and D bladder cancer, 2 had positive tests. If the leukocytes from advanced bladder cancer patients were preincubated briefly with prostaglandin E2, the negative response was converted to positive. Of 189 patients with diseases of other organs, 2 had positive tests. Patients with acute or chronic cystitis had negative tests. The sensitivity of the assay was 88 per cent; specificity was 95 per cent. The bladder cancer extracts prepared from metastatic tissue or the tissue-cultured cell line, T24, had similar activity in the assay. Normal bladder tissue did not share the bladder cancer organ-specific neoantigen nor did cancers of other organs. Bladder epithelial cells expressed the OSN before they acquired invasive properties since patients with dysplastic bladder epithelium or in-situ cancer had positive tests. Antitumor immunity was often detectable before a recurrence became obvious by cystoscopy or cytology of urine and became undetectable quickly after removal of the bladder cancer. Of 100 patients with prior bladder cancer without evidence of exophytic tumor, 18 had positive tests; the possibility must be considered seriously that some had precancerous changes which formed no visible gross abnormalities. The results suggested that antitumor immunity to bladder cancer was a sensitive indicator of precancerous or cancerous changes existing in epithelial cells.

Disease-related lymphocyte cytotoxicity in rats bearing transitional cell carcinoma of bladder. Effect of immunomodulators

Blood lymphocytes from rats bearing transitional cell carcinoma (TCC) of the bladder were studied for their cytotoxicity in vitro against xenogeneic YAC-I target and against syngeneic TCC cells. Control lymphocytes were obtained from age and sex-matched syngeneic rats. The following differences were observed: (1) lymphocytes from TCC-bearing rats were cytotoxic to syngeneic TCC target cells whereas those from control rats were not; (2) lymphocytes from TCC-bearing and control rats were cytotoxic to NK sensitive YAC-I cells; however, NK cells from TCC-bearing rats were more adherent to nylon wool-columns than NK cells from control rats. The adherent and non-adherent cells from TCC-bearing rats were both cytotoxic to syngeneic TCC target cells. Levamisole treatment of effector cells from TCC-bearing rats did not affect the NK activity, yet it increased the cytotoxicity of non-adherent cells on TCC target cells. Treatment of the adherent cells with poly-I:poly-C increased slightly their NK activity on YAC-I cells and their anti-TCC cytotoxicity. However, a marked increase in the cytotoxicity by both adherent and non-adherent cell fractions was observed on TCC target cells pretreated with poly-I:poly-C. A disease-related cytotoxicity of lymphocytes from rats bearing TCC has been observed. Treatment of TCC target cells with poly-I:poly-C increased their susceptibility to lysis by the activated effector cells.

Cellular and humoral in vitro cytotoxicity against autologous bladder tumor cells in humans. Differences in autologous cytotoxicity against non-invasive and invasive transitional-cell tumors of the urinary bladder

Lymphocyte-mediated cytotoxicity (LMC), antibody-dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) were measured in a 51Cr assay against autologous tumor cells from 7 patients with non-invasive and 9 patients with invasive transitional-cell tumors of the urinary bladder (TCC). Cytotoxicity against the invasive tumor cells were demonstrated in CDC. Heat-inactivation of sera lead to complete loss of cytotoxicity while addition of allogenic serum restored cytotoxicity. The cytotoxicity of allogenic sera from controls against invasive tumor targets showed no differences when compared with autologous sera. No or very weak cytotoxicity was found against non-invasive tumor targets in autologous or allogenic assays. LMC and ADCC showed weak or no reactivities. Intensive wash or trypsinization of effector cells did not affect the cytotoxicity in LMC. The results indicate the occurrence of complement-dependent antibodies directed against target cells from invasive tumors of the urinary bladder while no cytotoxic responses were detectable when the target cells originated from non-invasive tumors.

Lymphocyte cytotoxicity against autologous bladder tumor cells in humans, investigated by use of a chromium-51 release assay

A technique for isolation of a single cell suspension of viable tumor cells from bladder tumor biopsies is described. By application of the tumor cells as targets in a 51chromium release assay, the cytotoxicity of autologous lymphocytes was measured in 38 patients with transitional-cell tumors of the urinary bladder. The lymphocyte-medicated cytotoxicity was evaluated in relation to the histological grade and clinical stage of the bladder tumors. No significant correlations were found between the autologous cytotoxicity and the grade or stage of the bladder tumors.

Plasma membrane-associated antigens on tumor cells derived from transitional-cell carcinoma of the human urinary bladder. II. Identification at the molecular level of plasma membrane-associated antigens

The surface proteins of seven human cell lines (three bladder carcinomas (TCC), two normal urothelial lines, one colon carcinoma, and one malignant melanoma) were labelled with 125I by the glucose oxidase-lactoperoxidase technique. Plasma membranes of the cells were isolated and analysed by sodium dodecyl sulphate electrophoresis (SDS-PAGE). When analysed under reducing conditions by staining with protein stain, approximately 45 distinct membrane polypeptides were detected in all membrane preparations. Although the banding patterns for all cell lines were very similar, a 23 K and a 110 K band were only seen in the five unrothelial lines. When the same gels were analysed by autoradiography, between 13 and 17 bands were detected for each of the cell lines. However, in this case, analysis revealed individual and stable banding profiles for each. One 180 K band and one 100 K band were only seen in the autoradiographs of the two normal lines but not in those of the tumor membranes. Analysis under non-reducing conditions gave similar results. The antigenicity of these surface components was analysed by incubating detergent extracts of surface-iodinated cells with IgG from a rabbit anti-TCC serum, absorbed with fetal bovine serum and bound to protein A (from Staphylococcus aureus) on a matrix of Sepharose 4B. Analysis of the eluates by autoradiography after SDS-PAGE under reducing conditions showed that many of the labelled polypeptides were antigenic and shared by all seven cell lines. Analysis of eluates from IgG preparations, exhaustively absorbed with human spleen, revealed the presence of at least one antigenic 110 K polypeptide confined to the membrane of the urothelial cells. Preparation of a rabbit antiserum to this 110 K component, isolated from one of the TCC-lines and tested by ADCC, indicated that this polypeptide constitutes an important surface antigen, present on urothelial cells of both TCC- and normal origin but absent from the colon carcinoma and malignant melanoma used for control.

Membrane-associated antigens on tumor cells from transitional-cell carcinoma of the human urinary bladder. I. Immunological characterization by xenogeneic antisera

An antiserum was raised in rabbits by immunization with a human tumor cell line, T-24, derived from transitional cell carcinoma (TCC) of the urinary bladder. The specificity of the IgG fraction was assessed by antibody-dependent cellular cytotoxicity (ADCC), using purified blood lymphocytes from healthy human donors as effector cells and seven human cell lines as target cells (T-24 and two additional TCC-lines, two normal urothelial lines, one colon carcinoma and one malignant melanoma). The IgG induced strong lysis of all seven target cell types. However, lysis of the five urothelial lines was significantly stronger than that of the control tumors. Conversely, antisera to either of the control tumors induced a significantly stronger lysis of the homologous tumors than of the urothelial cells. All antisera contained antibodies to fetal bovine serum but removal of these by absorption did not change the specificity of the ADCC reactions. When the anti T-24 serum was exhaustively absorbed with glutaraldehyde-fixed spleen homogenate, the cytotoxicity to the control tumor targets was abolished. Although absorption reduced the antibody titer of the IgG preparation, ADCC to the TCC targets remained at a high level. There was no difference in the degree of lysis of the three TCC targets. Lysis of the two target lines from normal urothelium was slightly lower than that of the tumor cells. The results indicate that the anti-TCC serum contained antibodies to one or several antigens shared by five urothelial cell lines but not by the control tumors. Whether or not it also contained antibodies to TCC-associated antigens remains to be established. The molecular basis for these findings will be given in the accompanying paper.

Cytotoxicity in vitro of blood lymphocytes from bladder cancer patients and controls to allogeneic or autologous tumor cells derived from established cell lines or short-term cultures

Blood lymphocytes from small groups of patients with transitional-cell carcinoma of the urinary bladder (TCC), clinical controls (CC) or healthy donors (HD) were tested for cytotoxicity in vitro by a 51Cr-release assay. The target cells were either from TCC or control tissue (long-term cultures) or were from short-term TCC cultures, kept in vitro for 10-20 transfer generations. When tested with allogeneic target cells from long-term cultures, TCC patients' lymphocytes tended to be more cytotoxic to TCC targets than to control targets. For the control lymphocytes this was not seen. A large proportion but not all of the cytotoxicity to these target cells was due to immunoglobulin-dependent cellular reactions, probably mediated by natural and disease-related antibodies of the lymphocyte donors, since it was significantly inhibited by Fab-fragments of rabbit antibodies to human immunoglobulin. Moreover, it was, to a large extent, mediated by lymphocytes with Fc-receptors for IgG. For seven of the TCC target cell cultures (two long-term and five short-term) autologous lymphocytes were also available for testing. While two patients were non-reactive to their own tumor cells, five reacted strongly in the autologous combinations. These autologous reactions were immunoglobulin-independent and were mediated by Fc-receptor-negative effector cells. In some instances, autologous cytotoxicity was accompanied by similar reactions to some of the allogeneic TCC targets but not to the allogeneic non-TCC control targets. On the basis of available information on HLA antigens in this material, the pattern of cross-reactions suggests that the cytotoxicity encountered in the autologous and in some of the allogeneic TCC-combinations may be the expression of antibody-independnet but specific CTL-mediated reactions, regulated by HLA. However, at the present stage of the investigation, other mechanisms must also be considered since the target cells from short-term TCC cultures were sometimes lysed by control lymphocytes in immunoglobulin-independent reactions. Whatever the explanation, the results show that the cytotoxicity observed in the in vitro systems is usually the net result of several different types of reaction. Which effector cell types and which mechanism of recognition will predominate in a given lymphocyte/target cell combination is greatly influenced by the nature and origin of the target cells used.

Lymphocyte-mediated lysis of tumor cells in vitro (ADCC), induced by serum antibodies from patients with urinary bladder carcinoma or from controls

IgG fractions from serum of patients with transitional-cell carcinoma of the urinary bladder (TCC), patients with carcinoma of the prostate (CC) and healthy donors (HD) were tested for their capacity to induce antibody-dependent lymphocyte-mediated cytotoxicity (ADCC) to tumor cells in vitro. Lymphocytes from healthy donors were selected for low natural cytotoxicity to the target cells from established cell lines of TCC or other origins. IgG was prepared by adsorption of serum to Sepharose-bound protein A from Staphylococcus aureus and subsequent acid elution. When tested against a panel of six different target cells, most individual IgG preparations from all three donor groups contained antibodies inducing ADCC to some of the target cells. When IgG preparations from II untreated TCC patients were studied for ADCC induction to the TCC target T24 and the colon carcinoma HT29, cytotoxicity to T24 was, on an average, significantly higher than that to HT29. For IgG preparations from 18 TCC patients, treated with radiotherapy, a similar difference was seen but was not statistically significant. IgG preparations from II patients with carcinoma of the prostate and from 12 healthy donors did not show this differences. Moreover, while individual IgG preparations from untreated TCC patients were, on the average, significantly more cytotoxic to T24 than those from either of the two control groups, no such differences were seen when HT29 was the target. On the contrary, IgG preparations from patients with prostatic carcinoma were significantly more cytotoxic to HT29 than those from healthy donors. The results suggest that TCC patients develop a disease-related humoral immune response, superimposed on a "natural" immunity to a variety of antigens on the target cells used. The nature of the antigens involved in these reactions remains to be established. However, the results are compatible with previous findings, in these patients, of a bladder-tumor-related cellular cytotoxicity, to a large extent caused by the patients' own antibodies.

Heterogeneity and mechanism of action of human natural killer lymphocytes: differential distribution of receptors for Helix pomatia haemagglutinin (HP receptors)

Neuraminidase-treated lymphocytes from the peripheral blood of normal human donors were fractionated on columns charged with Helix pomatia haemagglutinin (HP) coupled to Sepharose 4B. While lymphocytes lacking HP receptors (HP-) passed directly through the column (fraction I), lymphocytes with HP receptors (HP+) were subsequently eluted in two distinct fractions with two different concentrations of the competitive hapten N-acetyl-D-galactosamine (fraction II and III, respectively). The natural cytotoxicity of these lymphocytes to various tumour target cells (K562, T24, MANO, HCV29) was tested in a 51Cr release assay. Natural cytotoxicity was found in all three fractions recovered from the HP columns. In general, the cytotoxicity of the lymphocytes in fractions I and II was significantly enhanced over that of the unfractionated lymphocytes. Surface marker analysis and fractionation studies indicated that natural cytotoxicity in these target systems is exerted by both HP+ and HP- lymphocytes bearing Fc receptors for IgG. Since the HP receptor is considered to be a marker to T lymphocytes, the findings suggest that a significant fraction of these NK cells may be of T-cell lineage. The surface marker profiles of these NK cells are very similar to those of antibody-dependent K cells. Addition of Fab fragments of immunoadsorbent-purified rabbit antibodies to human immunoglobulin inhibited the natural cytotoxicity of HP-column-fractionated lymphocytes to various degrees, indicating that part but not all of it reflects antibody-dependent K-cell reactions. Since cytotoxicity in all three HP fractions was inhibitable in this way, the results suggest that immunoglobulin-dependent natural cytotoxicity may be displayed by both HP+ and HP- effector cells.

Cellular cytotoxicity in transitional cell carcinoma of the human urinary bladder - a summary

The cytoxicity in vitro fo peripheral blood lymphocytes from patients with carcinoma of the urinary bladder (TCC-bladder) against allogeneic target cells from established cell lines was studied by the 51Cr-release assay. Lymphocytes from both untreated and treated TCC-bladder patients have a significantly elevated mean cytotoxicity to TCC-bladder target cells. Tumour cell destruction by lymphocytes from TCC-bladder patients shows a clear disease related specificity. In TCC-bladder patients a superimposed cytotoxicity exists, probably reflecting reactions against one or several tumour - associated antigens. In treated patients this cytotoxicity may be masked by higher incidence of cross reaction.