Targeted therapies for prostate cancer against the prostate specific membrane antigen.

Prostate cancer is the most common cancer in men from Western industrialized countries and a significant proportion of patients progress to advanced metastatic disease, for which currently no curative treatment exists. Therefore, new therapeutic approaches need to be considered. Prostate specific membrane antigen (PSMA) is an integral, non-shed type 2 membrane protein that is highly and specifically expressed on prostate epithelial cells and strongly upregulated in prostate cancer. PSMA is also present in the neovasculature of other solid tumors. These findings have spurred the development of PSMA-targeted therapies and first-generation products have entered clinical testing. The proposed strategies range from targeted toxins and radionuclides to immunotherapeutic agents. The present review provides an overview of these approaches.

A bispecific diabody directed against prostate-specific membrane antigen and CD3 induces T-cell mediated lysis of prostate cancer cells.

BACKGROUND: Although cancer of the prostate is one of the most commonly diagnosed cancers in men, no curative treatment currently exists after its progression beyond resectable boundaries. Therefore, new agents for targeted treatment strategies are needed. Cross-linking of tumor antigens with T-cell associated antigens by bispecific monoclonal antibodies have been shown to increase antigen-specific cytotoxicity in T-cells. Since the prostate-specific membrane antigen (PSMA) represents an excellent tumor target, immunotherapy with bispecific diabodies could be a promising novel treatment option for prostate cancer. METHODS: A heterodimeric diabody specific for human PSMA and the T-cell antigen CD3 was constructed from the DNA of anti-CD3 and anti-PSMA single chain Fv fragments (scFv). It was expressed in E. coli using a vector containing a bicistronic operon for co-secretion of the hybrid scFv V(H)CD3-V(L)PSMA and V(H)PSMA-V(L)CD3. The resulting PSMAxCD3 diabody was purified from the periplasmic extract by immobilized metal affinity chromatography (IMAC). The binding properties were tested on PSMA-expressing prostate cancer cells and PSMA-negative cell lines as well as on Jurkat cells by flow cytometry. For in vitro functional analysis, a cell viability test (WST) was used. For in vivo evaluation the diabody was applied together with human peripheral blood lymphocytes (PBL) in a C4-2 xenograft-SCID mouse model. RESULTS: By Blue Native gel electrophoresis, it could be shown that the PSMAxCD3 diabody is mainly a tetramer. Specific binding both to CD3-expressing Jurkat cells and PSMA-expressing C4-2 cells was shown by flow cytometry. In vitro, the diabody proved to be a potent agent for retargeting PBL to lyze C4-2 prostate cancer cells. Treatment of SCID mice inoculated with C4-2 tumor xenografts with the diabody and PBL efficiently inhibited tumor growth. CONCLUSIONS: The PSMAxCD3 diabody bears the potential for facilitating immunotherapy of prostate cancer and for the elimination of minimal residual disease.

A recombinant PSMA-specific single-chain immunotoxin has potent and selective toxicity against prostate cancer cells.

Prostate cancer is the most commonly diagnosed form of cancer and the second leading cancer-related death among men in the Western civilization. Since no effective therapy exists for this tumor after progression beyond resectable boundaries, there is an urgent need for new treatment strategies. Prostate specific membrane antigen (PSMA) represents an excellent target on prostate cancer cells, and therefore specific immunotherapy may be a novel therapeutic option for the management of this tumor. We constructed a fully recombinant immunotoxin (A5-PE40) from a single-chain antibody fragment (scFv) against cell-adherent PSMA and a truncated form of Pseudomonas exotoxin A (PE40) lacking its natural binding domain Ia. The scFv A5 was obtained from a mAb elicited with native PSMA by phage display technology and direct selection on cells carrying the antigen. The bacterially expressed and purified immunotoxin A5-PE40 specifically binds to PSMA-positive prostate cancer cells and induces a 50% reduction of viability (IC50) at a concentration of 20 pM, while PSMA-negative cells remain unaffected. Due to its high and specific toxicity this recombinant immunotoxin is a promising candidate for therapeutic applications in patients with prostate cancer.

Antitumoral effect of recombinant mistletoe lectin on chemically induced urinary bladder carcinogenesis in a rat model.

BACKGROUND: The objective of this study was to determine the effect of intravesically applied, recombinant, galactoside specific mistletoe lectin (rML) on chemically induced tumor development in the urinary bladder of rats. METHODS: For tumor induction, rats were treated with four biweekly 1.5 mg doses of N-methyl-N-nitrosourea (NMU) intravesically (Weeks 0, 2, 4, and 6). The control group (n = 39 + 17 rats) received no other treatment. The four therapy groups also received rML twice weekly according to one of the following instillation regimens: 1) 30 ng rML per instillation from Week 8 to Week 13 (Group a: n = 14 rats), 2) 150 ng rML per instillation from Week 8 to Week 13 (Group b: n = 23 + 15 rats), 3) 30 ng rML per instillation from Week 14 to Week 19 (Group c: n = 22 rats), and 4) 150 ng rML per instillation from Week 14 to Week 19 (Group d: n = 19 rats). After the rats were asphyxiated at Week 21, the urinary bladders were excised in toto and examined histopathologically. To study the immunomodulatory effects of intravesically applied rML, 17 animals from the control group and 15 animals from Group b were asphyxiated at Week 13, and urinary bladder tissue was analyzed by semiquantitative reverse transcriptase-polymerase chain reaction analysis for mRNA expression of interferon-gamma, interleukin-10, and Fas ligand. RESULTS: By Week 21, atypical hyperplasia and neoplastic transformation were found in 82% of the animals in the control group. In contrast, in all four cohorts that were treated with rML, significantly lower rates of atypical hyperplasia and neoplastic transformation were found (Group a, 50%; Group b, 52%; Group c, 45%; and Group d, 42%). By Week 13, in the bladder tissue of 15 rML-treated animals from Group b, lower expression of interleukin-10 mRNA was measured, whereas the expression levels of interferon-gamma mRNA and Fas ligand mRNA were comparable to those of 17 animals from the control group. CONCLUSIONS: The current data provide evidence for an inhibitory effect of rML on experimental urothelial carcinogenesis that does not seem to be due to interferon-gamma and/or interleukin-10 dependent mechanisms.

Comparison of the activation status of tumor infiltrating and peripheral lymphocytes of patients with adenocarcinomas and benign hyperplasia of the prostate.

BACKGROUND: The presence of lymphocytic infiltration in prostate carcinomas has been shown to have prognostic relevance. However, it is not yet clear if this infiltrate represents a tumor-specific activated cell population or not. Therefore, the aim of the present study was to characterize the activation status of freshly isolated tumor infiltrating lymphocytes (TIL) from prostate carcinomas (PCa) and benign hyperplasia (BPH) with respect to the mRNA expression of cytokines and apoptotic factors. METHODS: TIL were isolated from mechanically disaggregated tumor material by gradient centrifugation. The cells of the interphase were depleted from epithelial cells with anti-human epithelial antigen magnetic beads and then CD3(+)- lymphocytes were selected with magnetic beads against this determinant. In these pure lymphocyte preparations the mRNA expression of IL-1, IL-10, IFN-gamma, TNF-alpha, Fas and Fas ligand was determined by using a semiquantitative RT-PCR. Contamination with tumor cells was excluded by a PCR for PSA and PSMA. RESULTS: The CD3(+)-TIL from 21 patients with PCa and 20 patients with BPH expressed significantly higher levels of IL-10- and Fas ligand-mRNA compared to the autologous CD3(+)- PBL, whereas the expression of IL-1-, TNF-alpha- and Fas-mRNA was not different in either cell population. In contrast, the mRNA levels of IFN-gamma were significantly higher only in the CD3(+)-TIL from the carcinomas but not from the BPH compared to autologous CD3(+)-PBL. CONCLUSIONS: Since high levels of IFN-gamma have been reported to be produced by specifically lytic lymphocytes, our results suggest the presence of specifically activated TIL in the prostate carcinomas but not in the BPH, whereas inflammatory activated TIL are present both in the carcinomas and the BPH.

Enhanced expression of IFN-gamma mRNA in CD4(+)or CD8(+)tumour-infiltrating lymphocytes compared to peripheral lymphocytes in patients with renal cell cancer.

The mRNA expression of the cytokines IFN-gamma, IL-10 and TNF-alpha and the proapoptotic factor Fas ligand (FasL) was compared in freshly isolated CD4(+)and CD8(+)tumour-infiltrating lymphocytes (TIL) and simultaneously obtained autologous CD4(+)and CD8(+)peripheral blood lymphocytes (PBL) from 20 patients with renal cell carcinomas (RCC). TIL were isolated from mechanically disaggregated tumour material and PBL from peripheral blood by gradient centrifugation. The cells of the interphase were depleted from tumour cells with anti-human epithelial antigen magnetic beads and then positive selection was performed with anti-CD4 or anti-CD8 magnetic beads. In these pure lymphocyte preparations the constitutive expression of cytokine and FasL mRNAs was determined by using a PCR-assisted mRNA amplification assay. In the CD4(+)TIL from the 20 patients with RCC, levels of mRNAs encoding for IFN-gamma (P

Construction and in vivo evaluation of an anti-PSA x anti-CD3 bispecific antibody for the immunotherapy of prostate cancer.

BACKGROUND: Cross-linking of tumor antigens with the T-cell associated CD3 antigen can be effectively achieved by bispecific monoclonal antibodies and lead to an increase in antigen-specific cytotoxicity in T cells. Because of the high organ specificity of the prostate specific antigen (PSA), a bispecific antibody (BiAb) directed against this antigen and CD3 may be a tool for a highly specific immune therapy of prostate cancer. METHODS: For generating BiAb, the quadroma technique was used. Binding properties both to CD3 and PSA were shown by flow cytometry with the CD3 expressing Jurkat cell line and fluorescein-labeled PSA. Specific tumor cell lysis was tested with the PSA expressing prostate carcinoma cell line LNCaP as target and interleukin-2 activated human peripheral blood lymphocytes as effector cells in a chromium-51-release assay. For in vivo evaluation of the BiAb, a nude mouse model was used. The mice were inoculated with LNCaP prostate carcinoma cells. Animals with growing tumors were treated with 100 micrograms BiAb and 5 x 10(6) effector cells. RESULTS: Three stable quadromas producing anti-CD3 x anti-PSA BiAb were established. From the culture supernatant of one quadroma, BiAb was separated by affinity chromatography and tested in vitro and in vivo for its ability to target effector T lymphocytes against appropriate tumor cells. In vitro, a specific lysis of PSA expressing prostate carcinoma cells was demonstrated. In vivo, a significant reduction in tumor growth (p < 0.05) could be shown in nude mice treated with BiAb and effector cells as compared to a group treated only with effector cells and an untreated control group. CONCLUSION: In the present study, an anti-CD3 x anti-PSA-BiAb was demonstrated to be effective against prostate carcinoma cells in vitro and in vivo. Therefore this BiAb may be a tool for the immunotherapy of prostate cancer.

Systemic and local immunomodulatory effects of intravesical BCG therapy in patients with superficial urinary bladder carcinomas.

PURPOSE: The aim of the present study was to elucidate whether only local, or also systemic immunomodulatory effects may be induced by intravesical BCG therapy of superficial urinary bladder cancer. MATERIALS AND METHODS: A total of 37 patients with stages Ta to T1b superficial transitional cell bladder carcinomas received 6 weekly BCG instillations after transurethral resection of the tumor. In a first group of 19 patients blood was taken before each BCG instillation and 6 weeks after the last one. In a second group of 18 patients blood and urine was taken before and 2, 6, and 24 hours after each BCG instillation. In the mitogen-stimulated whole blood cell cultures and in the urine samples the levels of the cytokines IL-1beta, IL-2, IL-10, TNF-alpha and IFN-gamma were determined by enzymoimmunological tests. Additionally, in all plasma and urine samples the levels of TNF-p75-receptor (TNF-p75-R) were measured. RESULTS: Comparison of ex vivo leukocyte cytokine production in the blood cell cultures of the patients of group I revealed no significant change in the levels of the cytokines. In contrast, TNF-p75-R plasma levels increased significantly during the experimental time of 12 weeks (p < or =0.01). In the blood cell cultures of the group II patients a different daytime variation of cytokine production was seen, compared to the 19 healthy controls. After BCG instillation the normal peak cytokine production in the evening was suppressed. A significant rise in plasma TNF-p-75-R levels was measured 24 hours after BCG instillation (p < or =0.05). In the urine of these patients significantly higher levels of all measured cytokines and TNF-p75-R were observed 6 to 24 hours after the instillation. CONCLUSIONS: The results suggest that besides the well known local immune activation, BCG instillation also leads to a modulation of peripheral immune mechanisms.

Biological effects of natural and recombinant mistletoe lectin and an aqueous mistletoe extract on human monocytes and lymphocytes in vitro.

Mistletoe lectin is thought to constitute the active principle in extract preparations from mistletoe, which are widely used as immunomodulators in adjuvant tumor therapy. However, no study exists which compares the immunological potency of different well-defined mistletoe lectin preparations on human immune cells. Therefore, in the present study the biological effects of an aqueous mistletoe extract, standardized for mistletoe lectin I (eML), the isolated natural mistletoe lectin (nML), and the recombinant form of this lectin (rML) on human peripheral blood monocytes and lymphocytes were compared with respect to cell viability and cytokine induction. After 48-hr incubation of peripheral blood mononuclear cells (PBMC) with rML, nML, and eML, a continuous concentration-dependent decrease in cell viability was found with an IC50 of about 3 ng/ml for rML and nML and 10 ng/ml for eML, respectively. This effect also was seen when isolated lymphocytes and monocytes were separately incubated with the lectin preparations. After incubation of PBMC and isolated monocytes of 5/10 blood donors with eML, an increase in cell viability was found at lectin concentrations between 10 and 1,000 pg/ml. This effect was not seen with the pure lectin preparations nML and rML. After 48-hr incubation of PBMC with rML, nML, and eML, induction of IL-1-beta, TNF-alpha, IL-2, IL-6, and IL-10 but not IFN-gamma was measured. For IL-1-beta it could be shown that cytokine induction took place at a broad lectin concentration range (0.1-100 ng/ml). Cytokine levels varied greatly in the PBMC cultures of the different blood donors. When monocytes were separately incubated with eML, nML, and rML for 48 hr, high levels of IL-1-beta were found. In contrast, in cultures of separated lymphocytes from the same donors only a minimal production of IL-1-beta and no production of IFN-gamma was found after incubation with rML, nML, and eML. It is concluded that there are quantitative differences in the immunomodulatory effects of the mistletoe lectin preparations on human monocytes and lymphocytes. Therefore, measurement of cell viability and cytokine induction may be a diagnostic laboratory tool to determine the immunological potency of various mistletoe preparations and may help to clarify the clinical benefit of therapies with these substances.

Semiquantitative analysis of Th1 and Th2 cytokine expression in CD3+, CD4+, and CD8+ renal-cell-carcinoma-infiltrating lymphocytes.

The mRNA expression of Th1 and Th2 cytokines was compared in freshly isolated CD3+ tumor-infiltrating lymphocytes (CD3+ TIL) and in autologous CD3+ peripheral blood lymphocytes (CD3+ PBL) obtained simultaneously from 20 patients with renal cell carcinomas (RCC). In addition cytokine expression was compared in CD4+ TIL and CD8+ TIL from another group of 20 patients with RCC. TIL were isolated from mechanically disaggregated tumor material and PBL from peripheral blood by gradient centrifugation and subsequent selection with anti-CD3, anti-CD4 or anti-CD8 magnetic beads. In these pure lymphocyte preparations the constitutive expression of interleukin-1 (IL-1), IL-2, IL-10, interferon gamma (IFNgamma), and tumor necrosis factor alpha (TNFalpha) was determined by using a polymerase-chain-reaction-assisted mRNA amplification assay. In the CD3+ TIL, levels of mRNA for IFNgamma, IL-10, IL-1 and TNFalpha were significantly higher than in the autologous CD3+ PBL whereas IL-2 expression was rather low and did not differ in the two populations. Comparison of cytokine mRNA expression in CD4+ TIL and simultaneously obtained CD8+ TIL revealed a significantly higher expression of IFNgamma in the CD8+ cells. These data reflect an in vivo activation of RCC-infiltrating lymphocytes at the mRNA level with respect to the Th1 as well as the Th2 immune response. Th1 activation seems to be most evident in the CD8+ TIL.

Th1 and Th2 cytokine response patterns in leukocyte cultures of patients with urinary bladder, renal cell and prostate carcinomas.

As a decreased production of Th1 cytokines by stimulated peripheral blood leukocytes has recently been shown in patients with various carcinomas, the present study was performed to determine whether these patients also exhibit a Th1/Th2 imbalance compared to healthy controls. We measured the production of the Th1 cytokines IL-2 and IFN-gamma as well as the Th2 cytokines IL-4, IL-6 and IL-10 in mitogen-stimulated peripheral blood mononuclear cell (PBMC) cultures of patients with urinary bladder carcinomas (n = 47), prostate carcinomas (n = 111) and renal cell carcinomas (n = 67) as compared to 40 age-matched healthy controls. In the PBMC cultures of the tumor patients, the levels of the Th1 cytokines IL-2 and IFN-gamma were lower as compared to the controls. For IFN-gamma, the differences were highly significant and in the patients with renal cell carcinomas it could be shown that the values decreased with increasing tumor mass. In contrast, the levels of the Th2 cytokines IL-4, IL-6 and IL-10 were comparable in the PBMC cultures of tumor patients and controls. From these results, it is concluded that there is only a malfunction in Th1 cells but no switch from a Th1 type to a Th2 type cytokine profile in the PBMCs of cancer patients.

Correlation of clinical and immunological parameters of metastatic renal cell carcinoma patients undergoing therapy with interleukin 2, interferon-alpha and retinoic acid.

IFN-gamma production in whole blood cell cultures (WBCC), and TNF-receptor p75 (TNF-R-75) plasma levels were measured as two independent immunological parameters in a group of 67 untreated renal cell carcinoma (RCC) patients at different clinical stages, and 40 age matched healthy controls. In the blood cell cultures of the tumor patients the levels of IFN-gamma were significantly lower compared to the controls and the values decreased with increasing tumor mass. In contrast, TNF-R-75 plasma levels were significantly higher in the tumor patients and increased with tumor stage. Additionally serial assessments of these parameters were studied in another group of 15 patients with advanced RCC during treatment with IL-2, IFN-alpha and retinoic acid according to three different protocols in order to search for any correlation between the biological marker values and the clinical response to treatment. During each 5 day cycle of high dose IL-2/IFN-alpha combination therapy (protocol 1) IFN-gamma-levels in the WBCC were markedly decreased, whereas the plasma levels of TNF-R-75 were increased. During low dose, long-term continuous IFN-alpha/IL-2 administration (protocol 2) in two patients a clear increase of the ex vivo leukocyte IFN-gamma production was seen for the first 5 and 6 months of treatment, respectively, which could be correlated to stable disease for this time. When progression was diagnosed, IFN-gamma levels in the WBCC decreased. In the WBCC of the other four patients with progressive IFN-gamma levels were rather low throughout (< 10 ng/ml) and no clear changes were measured. During low does IFN-alpha and 13-cis-retinoic acid therapy in repetitive weekly cycles (protocol 3) two patients had stable disease for 6 and 14 months respectively. In the WBCC cultures of these patients IFN-gamma production was higher during stable than during progressive disease. The other two patients with tumor progression had a very low leukocyte IFN-gamma production and high plasma levels of TNF-R-75. It is concluded that IFN-gamma levels in WBCC and TNF-R-75 plasma levels may be useful parameters for the immunological monitoring of therapies with biological response modifiers. Low IFN-gamma values and high TNF-R-75 levels may be predictive of tumor progression and bad prognosis.

Comparison of the effects of various clinically applied mistletoe preparations on peripheral blood leukocytes.

The aim of the present study was to compare the biological effects of 12 different clinically applied mistletoe preparations (I, II, III and IV) from the host trees "pinus" (P), "malus" (M), "abies" (A) and "quercus" (Q) on human leukocytes. When the preparations I-P, II-P, III-P and IV-A were added to the whole blood cell cultures of 37 cancer patients (breast cancer, n = 22, colorectal cancer, n = 15) and 34 healthy controls, a significant induction of the cytokines IL-1-beta, IL-2, IL-6, IL-10 and TNF-alpha was found with preparation I-P. A significant induction of IL-1-beta and TNF-alpha was obtained with the preparations II-P and III-P as compared to the nonstimulated control cultures. Induction of IFN-gamma was not found with any preparation. Cytokine induction was comparable in the blood cell cultures of the tumor patients and the healthy controls. When the clinical preparations I-P, I-M, I-Q, II-P, II-M, II-A, III-P, III-M, III-A and IV-P, IV-M, IV-A were tested in cultures of peripheral blood mononuclear cells from 5 healthy donors, differences in the induction of cytokine production and apoptosis were seen after addition of the mistletoe preparations from different host trees. Increased levels of IL-1-beta were found after addition of the preparations I-P and I-M, increased levels of TNF-alpha were measured after addition of preparations I-P and III-A. Induction of apoptosis was most evident with the preparations I-M, I-Q, III-M and IV-A. Neither cytokine induction nor apoptosis could be correlated to the amount of lectins found in the preparations. Stimulation of separated CD4(+)-, CD8(+)- and CD14(+)-cells from 5 healthy donors with the above noted preparations revealed an induction of IL-1-beta and TNF-alpha production by the preparations I-P, I-M and I-Q mainly in monocytes and to a minimal extent in lymphocytes. Also apoptosis was seen mainly in CD14(+)-monocytes. From these results it is concluded that both, apoptosis and cytokine production are induced differentially in leukocyte cultures by clinically applied mistletoe preparations. However, there is no correlation between the biological effects and the lectin content of the various preparations and none of them were comparable with respect to the extent of these effects. Therefore, it may be expected that clinical studies with different preparations are not comparable either.

Analysis of the immune reactivity of infiltrating and peripheral lymphocytes from patients with renal cell carcinoma by measuring cytokine secretion.

The immunological properties of tumour-infiltrating (TIL) and peripheral blood lymphocytes (PBL) from 29 patients with renal cell carcinomas were characterized with respect to their phenotypic expression and cytokine production. TIL were isolated from mechanically disaggregated tumor material and PBL from peripheral blood by gradient centrifugation. To eliminate all non-lymphoid cells, CD3-positive cells were specifically separated from these cell fractions with anti-CD3 magnetic beads. These pure CD3-positive PBL (CD3+PBL) and TIL (CD3+TIL) were cultured with pokeweed mitogen and the levels of the cytokines interleukin-1alpha (IL-1 alpha), IL-1 beta, IL-2, interferon gamma (IFNgamma), and tumor necrosis factor alpha (TNFalpha) measured in the 4-day post-inductional cell culture supernatants. In all cell cultures a wide range of cytokine values was found, indicating a large variation in the immunological activity of the lymphocytes of each individual. When the cell cultures of the CD3+TIL and CD3+PBL were compared in each patient similar values for IL-1 alpha, IL-1 beta, IFNgamma and TNFalpha were found. However CD3+TIL produced significantly lower levels of IL-2 than CD3+PBL upon mitogenic stimulation. This may be due to a lower CD4/CD8 ratio in the CD3+TIL as compared to the CD3+PBL. These results suggest that there are no fundamental qualitative and quantitative differences in the lymphokine-producing capacity of CD3+TIL and CD3+PBL derived from patients with renal cell carcinomas.

Cytokine production in leukocyte cultures during therapy with Echinacea extract.

We measured the levels of the cytokines IL-1-alpha, IL-1-beta, IL-2, IL-6, TNF-alpha, and IFN-gamma in culture supernatants of stimulated whole blood cells derived from 23 tumor patients undergoing a 4-week oral treatment with a spagyric extract from Echinacea angustifolia, Eupatorium perfoliatum, and Thuja occidentalis (Echinacea complex). All patients had had curative surgery for a localized solid malignant tumor. Blood was taken before treatment and after 2 and 4 weeks of therapy. Twelve untreated tumor patients at the same clinical stage, also after curative surgery, served as a control group. In the blood cell cultures of all patients, a rather wide range of cytokine levels was found. After therapy with Echinacea complex, no significant alteration in the production of the cytokines could be seen in comparison to the controls, and also the leukocyte populations remained constant. We conclude that at this application and dosage, the therapy with Echinacea complex has no detectable effect on tumor patients' lymphocytes activity as measured by their cytokine production.

Immunosuppressive activity of sera from patients with colorectal and gynecological carcinomas as evaluated by impaired IFN-gamma, IL-1 alpha and TNF-alpha production of human peripheral mononuclear cells.

The sera from patients with preoperative colorectal and gynecological carcinomas (ovarian and breast cancer) were investigated for their putative immunosuppressive activity (ISA). ISA was measured by determining the changes in the production of IFN-gamma, IL-1 alpha and TNF-alpha by human peripheral mononuclear cells (PBMC) from six normal donors. Phytohemagglutinin-stimulated PBMC were incubated with sera from patients with colorectal and gynecological carcinomas and healthy controls and in the 4-day post-inductional supernatants the cytokines were measured by an enzymoimmunological assay (ELISA). Sera from patients with carcinomas significantly decreased the IFN-gamma production as compared to the controls. In the cultures containing sera from patients with colorectal and ovarian but not breast carcinoma, significantly lower levels of IL-1 alpha and TNF-alpha were measured compared to the cultures with sera from healthy controls.

Comparison of cytokine production in blood cell cultures of healthy children and adults.

The production of the cytokines IL-1-alpha, IL-1-beta, IL-2, TNF-alpha, and INF-gamma was measured by a sensitive immunological assay in stimulated whole blood cell cultures from 52 healthy children (33 aged from 1 to 9 years and 19 aged between 10 and 17 years) and 67 healthy adults. When the higher absolute mononuclear cell counts in the peripheral blood samples of the children were taken into account, the relative production of all measured cytokines was lower in the cell cultures of the children than of the adults. In the group of the younger children (< 10 years) the differences were significant for all measured cytokines. In the group of older children (> or = 10 years) the values were higher than in the younger children but lower than in adults. The findings indicate that the cellular immunological competence is or can be reduced in children and adolescents, particularly young children below 10 years of age. There seems to be a gradual development of cytokine production during childhood.

Cytokine production in whole blood cell cultures of patients with Crohn's disease and ulcerative colitis.

Levels of the cytokines interleukin-1-alpha, -1-beta, and -2 (IL-1-alpha, IL-1-beta, IL-2), tumor necrosis factor-alpha (TNF-alpha), and interferon-gamma (IFN-gamma) were measured in the mitogen-stimulated whole blood cell cultures from 96 patients with Crohn's disease (48 untreated, 12 treated with sulfasalazine, 36 treated with corticosteroids), 74 patients with ulcerative colitis (21 untreated, 25 treated with sulfasalazine, 28 steroid treated), and 360 healthy controls. The cytokines were measured 4 days after induction by a sensitive immunoenzyme assay. In the blood cell cultures of the untreated and sulfasalazine treated patients with Crohn's disease and ulcerative colitis higher levels of TNF-alpha, IL-1-alpha and IL-1-beta were found whereas IL-2 production was decreased and IFN-gamma-production was not significantly different as compared to the controls. Leukocytes of the corticosteroid-treated patients with both diagnoses showed a lower production of all measured cytokines compared to the untreated patients. The same results were obtained, when the somewhat different counts of mononuclear cells in the peripheral blood of the patients and controls were taken into account. The elevated production of proinflammatory cytokines in the blood cell cultures suggests a systemic immune activation in patients with inflammatory bowel disease.

Increased plasma concentrations for type I and II tumor necrosis factor receptors and IL-2 receptors in cancer patients.

Using enzyme-linked immunoabsorbent assays for the soluble tumor necrosis factor (TNF) receptors type I (p55) and type II (p75) and IL-2 receptor we determined their levels in the plasma of 378 patients with various solid carcinomas, 56 patients with benign tumors, and 241 healthy controls. The plasma concentrations of both TNF receptors as well as the IL-2 receptor were significantly higher in the cancer patients than in the healthy controls, independent of the origin or histology of the tumor. The incidence and the extent of the receptor increase correlated with the extent of the disease. In the patients with benign tumors plasma levels of TNF receptor p75 and IL-2 receptor were not significantly different from the controls.

Cytokine production in whole blood cell cultures of patients undergoing therapy with biological response modifiers or 5-fluorouracil.

We have measured the levels of interferon gamma (IFN gamma), tumor necrosis factor alpha (TNF alpha), interleukin-1 alpha (IL-1 alpha), IL-1 beta, and IL-2 in the whole blood cell culture supernatants of 43 tumor patients undergoing a treatment with biological response modifiers or a conventional therapy with 5-fluorouracil and leucovorin. In the blood cell cultures of the 16 patients who received 5-fluorouracil and leucovorin IFN gamma levels decreased (P < or = 0.01) and TNF alpha levels rose (P < or = 0.05) during each therapy cycle. However, in the blood samples a declining number of total leukocytes and lymphocytes was measured (P < or = 0.05). Progressive disease could be correlated to a tendency towards lower IFN gamma levels in the pretherapeutic cultures of these patients. The second group analyzed consisted of 8 patients receiving a low-dose IL-1 beta therapy. In this group we found either an unchanged or an augmented IFN gamma production of the blood cells during treatment. In the group of 13 patients receiving low-dose recombinant IL-2 (< or = 4.5 x 10(6) IU m-2 day-1) significantly increasing IFN gamma levels were seen in the blood cell cultures during the therapy (P < or = 0.05), although total leukocyte counts decreased. In this group, 4 had stable disease for at least 2 months and 9 patients had tumor progression under therapy. In the cultures of the latter a tendency towards lower IFN gamma values was found. Finally, the cytokine production in the blood cell cultures of 6 patients receiving a combination therapy of IFN alpha and high-dose IL-2 was studied. During this therapy a dramatically reduced production not only of IFN gamma but also of all other measured cytokines was found. In this group all patients had tumor progression under therapy. It is concluded that the measurements of cytokine production in a reproducible whole blood culture system may be useful for monitoring immunological therapies and may help us to find out which doses of biological response modifiers have enhancing or suppressive effects on the functions of the immune cells.