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R J Scheper

Publications and source records attributed to R J Scheper.

At least 217 records · Page 12Linked to original sources
PubMed1991

Differentiation dependent expression of P-glycoprotein in the normal and neoplastic human kidney.

Adult renal cell carcinoma (RCC) is clinically resistant to chemotherapy. However, in nephroblastoma (NBL) chemotherapy has increased survival dramatically. We studied the P-glycoprotein (P-gp) expression of 18 RCC and 9 NBL as well as 1 benign renal adenoma and fetal renal tissue using three different monoclonal antibodies (MRK-16, C-219, JSB-1). P-gp was found positive with all three antibodies in 12/18 RCC, while only 2 tumors were completely negative. Staining varied with respect to intensity and number of positive cells [5%-90%]. Intense staining was seen at the apical side of malignant tubules in well differentiated parts of RCC and in tubular structures of the benign renal adenoma. Poorly differentiated parts of the tumors showed less staining. In NBL blastemal parts were negative. In 4/8 specimens showing focal epithelial differentiation, however, the luminal side of more differentiated tubular structures did stain, strongly resembling P-gp staining in the developing fetal human kidney. These results indicate that P-gp expression in normal (fetal) human kidney as well as in benign and malignant tumors derived from this organ depends on the degree of differentiation of tubules, which may have implications for chemotherapy sensitivity in both malignant tumors.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1991

Successful induction of allergic contact dermatitis to mercury and chromium in mice.

Availability of reproducible mouse models for allergic contact dermatitis (ACD) to the metal allergens nickel, mercury and chromium, would be of great value for pathogenetic and preventive studies. We explored epicutaneous sensitization to nickel, mercury and chromium in mice in which oral grooming of the sensitization site was prevented by a plaster cast around the abdomen and lower thorax. This procedure was based on earlier findings that oral ingestion of allergen could prevent contact sensitization. The present results show that BALB/c mice can be readily sensitized to mercury and chromium using this epicutaneous casting method, without the further use of adjuvants. With nickel, however, neither this method, nor conventional methods involving the use of Freund's complete adjuvant (FCA) were effective.

Animals↗
PubMed1991

P-glycoprotein expression in malignant lymphoma and reversal of clinical drug resistance with chemotherapy plus high-dose verapamil.

P-glycoprotein is a transmembrane protein thought to function as an efflux pump to detoxify cells. It is associated with multidrug resistance in laboratory systems and has recently been found in human tumors associated with in vitro and clinical drug resistance. We used an immunohistochemical method employing two monoclonal antibodies, JSB-1 and C-219, to detect expression of P-glycoprotein in lymphoma patients. One of 42 newly diagnosed and untreated lymphoma patients (2%) and seven of 11 previously treated and drug-resistant patients (64%) had detectable levels of P-glycoprotein (P less than .001). Based on prior reports suggesting that verapamil sensitizes drug-resistant cancer cells to chemotherapy by competitive inhibition of the P-glycoprotein, we tested the efficacy of verapamil as a chemosensitizer in 18 patients with drug-refractory disease. All patients had previously failed or relapsed within 3 months of a doxorubicin-vincristine-containing drug regimen. Patients received day-1 cyclophosphamide, and 4-day continuous infusion doxorubicin and vincristine and oral dexamethasone (CVAD). CVAD was combined with 5-day continuous infusion verapamil given at maximally tolerated dose. Overall, 13 of 18 patients (72%) responded to treatment including five complete remissions (CRs; 28%). The median duration of response was 200 days and median survival was 242 days. The dose-limiting toxicity of the verapamil infusion was temporary cardiac dysfunction including hypotension, congestive heart failure, and cardiac arrhythmia. We conclude that the P-glycoprotein is uncommonly expressed in untreated lymphomas and frequently expressed in clinically drug-resistant disease, and that chemotherapy using CVAD plus maximally tolerated doses of verapamil results in a high response rate in patients carefully selected for clinical drug resistance.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1991

Inhibition of T suppressor cell function by local administration of an active cyclophosphamide derivative at the sensitization site.

In previous work, we have shown that local administration of active cyclophosphamide (CY) derivatives, or other cytostatic drugs, at the sensitization site induced a similar immunopotentiation to that of systemic CY. Since it is well documented that CY can inhibit suppressor cells, it was proposed that immunoenhancement by locally administered drugs might be based on a similar principle. The objective of the present study was to test this hypothesis, using an experimental model of Ts mediated suppression of delayed type hypersensitivity to sheep erythrocytes. In this model, mice are made tolerant to sheep erythrocytes by i.v. injection of a high dose of sheep erythrocytes. Local treatment of sheep erythrocytes-tolerant mice with the active CY derivative Z7557 at the site of attempted sensitization reversed suppression in a dose-dependent manner. Local treatment with the cytostatic drug etoposide (VP-16) and systemic CY treatment were also effective. In transfer experiments, the function of afferently acting suppressor cells was blocked by local treatment with Z7557 or systemic CY. These data support the concept of anti-suppressor cell activity of locally administered cytostatic drugs. As with CY, the pharmacological basis of this effect remains to be determined.

Administration, Topical↗
PubMed1991

Alterations in dendritic cell phenotype and function associated with immunoenhancing effects of a subcutaneously administered cyclophosphamide derivative.

A single systemic dose of cyclophosphamide (CY) has been shown to enhance cellular immunity in a variety of antigen models. The immunoenhancing effects of CY have been attributed to its ability to selectively abrogate suppressor cell function. Previous studies from our group have demonstrated that local administration of distinct cytostatic drugs at the sensitization site can induce a similar enhancement of delayed-type hypersensitivity as systemic CY, with the obvious advantage of avoiding systemic side-effects. In the present study we investigated the effects of local administration of an optimally immunopotentiating dose of the active CY-derivative Z 7557 and, in selected experiments, of etoposide (VP-16) and systemic CY on mononuclear cells in draining lymph nodes. Whereas CY caused a long-lasting and marked depletion of B-cell areas, locally administered Z 7557 and VP-16 relatively spared B cells and even induced an increase in B- and T-cell numbers in (keyhole limpet haemocyanin-) sensitized mice. At Day 4 the CD4/CD8 ratio was slightly reduced in drug-treated mice. Interestingly, drug treatment reduced the proportion of interdigitating cells staining with the monoclonal antibodies NLDC-145 and MIDC-8. Upon isolation, dendritic cells (DC) from sensitized, Z 7557-treated mice showed longer dendritic protrusions and an enhanced accessory cell function compared to DC from saline-treated controls. These findings suggest that immunoenhancing effects of cytostatic drugs may occur via an effect on DC.

Adjuvants, Immunologic↗
PubMed1990

Spectophotometric quantification of cell-cell adherence by an enzyme-linked immuno-cell adhesion assay.

In the present study a spectophotometric method was developed to determine the number of T cells binding to human epidermal keratinocytes (KC). In this cell adhesion assay the adherent T cells were detected with a cell-specific monoclonal antibody conjugated to horseradish peroxidase and the coloured substrate quantified in an ELISA reader at 492 nm. A correlation was demonstrated between the number of T cells and the extinction values measured. The enzyme-linked immuno-cell adhesion assay (ELICAA) was used to quantify KC/T lymphocyte adherence in a series of experiments designed to evaluate its reliability and reproducibility. Compared with the 51Cr-labelled adherence assay, the ELICAA was a safe, rapid and accurate method avoiding the use of radioactive material.

Antibodies, Monoclonal↗
PubMed1990

Identification of a 43-kDa nuclear antigen associated with proliferation by monoclonal antibody K 112.

Monoclonal antibody (MAb) K 112 was generated after a single intrasplenic immunization with a recurrent laryngeal squamous-cell carcinoma. The antibody detects a 43-kDa nuclear antigen, with a pI of 5.4, which is expressed only in cycling cells. Expression is typically seen in a granular pattern excluding the nucleoli. During mitosis the bulk of the antigen is diffusely distributed in the cytoplasm. Identical reactivity was observed for tissues or cells of all mammalian species tested. These data indicate that MAb K 112 recognizes a protein belonging to the class of cell-cycle-related nuclear antigen molecules.

Animals↗
PubMed1990

Production of monoclonal antibodies to squamous cell carcinoma antigens.

For therapeutic or diagnostic use of monoclonal antibodies in clinical oncology, high-affinity IgG antibodies to tumor-associated antigens have to be generated. In order to find out by what immunization schedule the chance to generate such antibodies is increased, we evaluated three different immunization protocols with and without attempts to induce tolerance to common tissue antigens. Mice were immunized either (1) by repeated intraperitoneal injections, (2) by a single intrasplenic injection, or (3) by an intraperitoneal injection followed by an intrasplenic booster. Whereas a single intrasplenic immunization resulted in low-affinity antibodies to tumor-associated antigen, high-affinity antibodies were generated with the other two protocols, although at a lower frequency. No benefit was seen from tolerance induction. The intraperitoneal/intrasplenic protocol was found to be superior over the other protocols because of minimal antigen dose and immunization time, as well as a higher frequency of hybridoma formation.

Animals↗
PubMed1990

Con A-nonreactive human alpha 1-acid glycoprotein (AGP) is more effective in modulation of lymphocyte proliferation than Con A-reactive AGP serum variants.

Human alpha 1-acid glycoprotein (AGP) has been shown to modulate various cellular and humoral immune reactions in vitro. Using glycosidase-modified derivatives of AGP, the importance of its carbohydrate moiety with regard to these effects has been noted. In normal serum, three molecular AGP forms interacting differently with concanavalin A (Con A) are present. The ratio of these forms is often changed during various physiopathological conditions. In this study, we could show that differences exist between the three AGP forms with regard to their immunomodulatory effectiveness. At physiological concentrations, the Con A-nonreactive variant AGP-A induced a stronger inhibition of the anti-CD3 stimulated lymphocyte proliferation than the other forms. Interestingly, AGP-A was also found to be responsible for the stimulation of lymphocyte proliferation induced by low AGP concentrations in vitro. Both immunomodulatory effects of AGP were abrogated by desialylation of the glycoprotein. These results support an immunomodulatory role of AGP in conditions characterized by a changed ratio of the differently glycosylated AGP forms.

Burns↗
PubMed1990

Major-histocompatibility-complex-class-II-positive cells and interleukin-2-dependent proliferation of immune T cells are required to reject carcinoma cells in the guinea pig.

Tumor immunity induced by bacillus Calmette-Guérin was studied in the line 10 hepatocellular carcinoma (line 10) in the strain-2 guinea pig. Line 10 immunity was investigated in vitro with a lymphocyte proliferation assay using line 10 tumor protein extracted with 3 M KCl and in vivo by adoptive transfer of line-10-immune spleen cells. Monoclonal antibodies against guinea pig leucocyte markers were used to block functional properties of the immune cells in order to determine which cell types or cell markers are involved in the immune response to the line 10 tumor. In vitro cells from the spleen, peripheral blood and regional lymph node of immune animals reacted with a proliferative response to line 10 protein. This antigen-specific response was caused by T cells and was regulated by major histocompatibility complex (MHC) class II molecules. In blocking experiments it was found that CT5 (anti-PanT), or MSgp4 [anti-(MHC class I antigen)] monoclonal antibodies did not block but sometimes stimulated the proliferative response. The effect of H159 (anti-PanT) was irregular, while H155 [anti-(T helper)], and 5C3 [anti-(IL-2 receptor)] monoclonal antibodies blocked the response almost completely. We studied the relevance of the results in vitro obtained and found that mAb 5C3 [anti-(IL-2 receptor)] inhibited the adoptive transfer of line 10 immunity, suggesting that the rejection of line 10 cells is caused by a mechanism that is interleukin-2 (IL-2)-dependent. Moreover, complement lysis of MHC-class-II-antigen-positive immune spleen cells inhibited completely the rejection of the line 10 tumor cell challenge in the adoptive-transfer experiments. In conclusion, our data show that MHC class II molecules or cells possessing these molecules are involved in immunity against line 10 tumor cells, as (a) monoclonal antibodies against MHC class II antigens inhibited the in vitro proliferative response of T cells to tumor antigens and (b) removal of MHC-class-II-positive immune spleen cells abrogated the antitumor effect in the adoptive-transfer experiments. Interleukin-2-dependent proliferation of immune T cells is required for the rejection of line 10 tumor cells.

Animals↗
PubMed1990

Major histocompatibility complex class II antigen expression during potentiation of line-10 tumor immunity after intralesional administration of bacillus Calmette-Guérin.

Intralesional injection of BCG into an established line-10 hepatocellular carcinoma in the strain-2 guinea pig causes regression of the tumor and induction of line-10 immunity. We found that the animals were already protected for a second challenge with line-10 tumor cells 7 days after BCG treatment. We studied whether this early induction of immunity was correlated with the expression of MHC class II antigens on line-10 tumor cells and was correlated with an increased expression of MHC class II antigens on leukocytes in the primary tumor and in the regional lymph node (Ln. axillaris accessorius). The MHC class II antigens and the leukocyte subpopulations were measured with monoclonal antibodies and flow cytofluorometry. In the draining lymph node the number of nucleated cells increased about 10-fold during the first 5 days after intralesional injection of BCG. At this time the MHC class II antigen expression of these cells was increased from 21%-32% in the naive controls to 39%-53% in animals with BCG-treated tumors. This implies that the number of MHC-class-II-positive cells increased about 20-fold in the draining lymph node. Surprisingly, the increase in percentage of MHC-class-II-antigen-positive cells was mainly due to an increase of IgM-positive B cells from 8%-11% to 22%-41% and an increase of IgG-positive B cells from 7%-27% to 25%-44%. In the tumor, BCG treatment induced a small increase of MHC-class-II-antigen-positive cells from 11%-12% to 15%-20%. Probably this increase came not from tumor cells but mainly from a BCG-induced infiltration of mononuclear cells, as an increase of T cells from 14% to 20%, an increase of macrophages from 8% to 18%, and an increase of B cells from 0 to 6% was observed. We conclude that the potentiation of anti-(line-10 tumor cell) immunity correlated with a 20-fold increase of MHC-class-II-antigen-positive cells in the lymph nodes and a small increase in the number of MHC-class-II-antigen-positive tumor-infiltrating cells.

Animals↗
PubMed1990

Local administration of cytostatic drugs enhances delayed-type hypersensitivity to Sendai virus in mice.

Cytostatic drugs known to exert immunomodulatory activity were studied in a local treatment protocol as to their effect on development of cell-mediated immunity to Sendai virus in mice. Strong enhancement of delayed-type hypersensitivity (DTH) was observed after treatment with the active cyclophosphamide (CY) derivative Z 7557 or the plant alkaloid VP-16 at the site of sensitization. Optimal enhancement of DTH was obtained after priming with subimmunogenic doses of Sendai virus and treatment with low, virtually nontoxic drug doses. Immunoenhancement is ascribed to elimination of CY-sensitive suppressor cells from the draining lymph nodes. The relevance of our findings with respect to protective immunity is discussed.

Adjuvants, Immunologic↗
PubMed1990

Enhancing effects of locally administered cytostatic drugs on T effector cell functions in mice.

It is well established that systemic treatment with cyclophosphamide (CY) can augment cell-mediated immunity by selective toxicity for suppressor cells. The present paper analyzes the effect of local administration of the cytostatic drugs Z 7557, an active CY-derivative, and VP-16 (etoposid) on the development of cell-mediated immunity to KLH in mice. Both drugs were found to induce a long-lasting state of enhanced DTH responsiveness. Induction of enhancement was antigen-specific but required a conjunction of local drug treatment and s.c. priming. This indicates that locally applied cytostatics interact with the sensitizing process in the draining lymph node. In support of this view, draining lymph node cells showed an enhanced capacity to transfer DTH reactivity to syngeneic recipients in vivo, and to proliferate and produce IL-2 and MIF in response to KLH in vitro. Kinetic studies showed a lag in appearance of antigen-specific T cell responsiveness in drug treated mice, which indicates that effector cells are also sensitive to the drugs. If local chemotherapy is properly scheduled, the effector cells recover quickly and, released from the putative inhibitory influence of suppressor cells, give rise to an augmented T cell response. As systemic treatment with cytostatic drugs is known to cause adverse side effects, restricting its use for immunopotentiating purposes, the present local chemotherapy protocol provides a new, versatile approach for enhancing cell-mediated immunity.

Animals↗
PubMed1990

Low allergenicity of clonidine impedes studies of sensitization mechanisms in guinea pig models.

During clinical trials, a clonidine transdermal device has been found to induce clonidine-specific allergic contact dermatitis in up to 25% of patients during a treatment period of 1 year. Using 3 different guinea pig strains, development was attempted of an experimental guinea pig model that would allow for in-depth studies into the mechanism of sensitization, and a possible role of transdermal device components. Transient low-level clonidine allergy could be obtained only in a minority of animals, with severe sensitization procedures departing from epicutaneous applications, combined with intradermal (adjuvant) FCA injections. Sensitization was not potentiated by additional booster procedures, including cyclophosphamide pretreatment, nor any of the putative cofactors (UV-treatments, C. parvum or acetaldehyde involvement) studied. These results suggest that the persistent skin contacts in man, with transdermal devices for sustained drug delivery, generate unique conditions favouring the development of allergic contact dermatitis, which are difficult to mimic in experimental animal models. Thus, clinical allergy may develop even to extremely weak sensitizing drugs that can be safely used orally, and escape most currently available predictive contact allergy animal models. Clinical studies remain unavoidable for studying factors that may reduce sensitization rates to more acceptable levels.

Administration, Cutaneous↗
PubMed1990

T lymphocytes and eosinophils in allergen-induced late-phase asthmatic reactions in the guinea pig.

The kinetics and phenotype of T lymphocytes infiltrating the airways of guinea pigs undergoing late-phase asthmatic reactions (LAR) were studied with monoclonal antibodies, cytofluorimetry, and immunocytochemistry. Challenge of sensitized animals with aerosolized ovalbumin was followed by early (2 h) and late-phase (17 h) bronchoconstriction. The induction of hypersensitivity, by aerosolized antigen, was associated with an increase in mucosal T cell numbers, which consisted almost entirely of CD8+ T cells. Following allergen challenge of fully sensitized animals, a biphasic rise in total T cell (CD3+) numbers was observed in the bronchial mucosa, peaking at 17 and 48 h. A similar pattern of T cell accumulation was observed in the bronchial adventitia but with an extra early peak at 2 h. In contrast to the T cell influx of the sensitization phase, the postchallenge infiltrate consisted largely of CD3+, CD8- cells. Eosinophil numbers were elevated in both submucosa and adventitia, with a single broad peak between 17 and 48 h. T cell infiltration was compared with eosinophil accumulation; while correlations between T cell and eosinophil numbers varied over the 96 h of the experiment, strong associations were observed between CD8+ numbers and eosinophils in the adventitia at 6 h (r = 0.733, p less than 0.01) and between CD3+ numbers and eosinophils in the submucosa at 72 h (r = 0.88, p less than 0.001). No significant changes were detected in T cell or eosinophil numbers in the lung parenchyma. There was a postchallenge increase in eosinophils (but not T cells) in bronchoalveolar lavage (BAL).(ABSTRACT TRUNCATED AT 250 WORDS)

Airway Resistance↗
PubMed1990

Oral induction of immunological tolerance to chromium in the guinea pig.

Metal alloys used in dentistry may elicit adverse side-effects. Contact allergic reactions to metals released from such alloys are among the most frequently encountered problems. In an earlier study, we observed that oral contacts with nickel or chromium salts did not sensitize, but rather decreased the risk of subsequent sensitization to these metals. In the present study, we focused on chromium allergy and extended our earlier observations by further dose-response studies. In addition, we compared different chromium valencies as to their potential oral tolerogenic effects. Development of immunological tolerance in chromium-fed guinea pigs was demonstrated by their inability to develop chromium hypersensitivity after a subsequent immunization attempt. For these studies, the techniques of immunization and skin testing were first improved. One feeding with a high dose of K2Cr2O7 (containing hexavalent chromium) was effective in full tolerance induction. In contrast, trivalent chromium (CrCl3) induced a distinctly lower degree of tolerance, whereas metallic chromium powder was not detectably tolerogenic after a limited number of feedings. Dose-frequency-response studies with K2Cr2O7 showed that full tolerance could also be induced by an increase in the number of feedings with sub-optimal tolerogenic doses. The present results therefore support our hypothesis that long-lasting oral contact with chromium-releasing metal alloys may ultimately result in strong immune tolerance to this metal in subjects without previous skin contact with it. This view is further supported by recent insights into the unique tolerogenicity of oral, as compared with gastro-intestinal, allergenic contacts.

Administration, Oral↗
PubMed1990

A 22-kd surface antigen detected by monoclonal antibody E 48 is exclusively expressed in stratified squamous and transitional epithelia.

After immunization of mice with viable cells of a metastasis of a laryngeal squamous cell carcinoma, a monoclonal antibody E 48 was obtained that detects an epitope present exclusively in squamous and transitional epithelium and their neoplastic counterparts. Immunoblotting revealed that E 48 recognizes a 22 kd molecule. Seventy-five of 76 squamous cell carcinomas from the head and neck, lung, cervix, and skin stained positively, whereas various adenocarcinomas from the colon, lung, and breast, and small cell lung carcinomas consistently stained negatively. The E 48 antigen, which is formaldehyde resistant, appears to be a reliable marker for differentiation of squamous cell carcinomas from adenocarcinoma, and small cell carcinomas.

Animals↗