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H Krause

Publications and source records attributed to H Krause.

At least 37 records · Page 2Linked to original sources
PubMed2001

The IL-15R alpha chain signals through association with Syk in human B cells.

The alpha-chain of the IL-15R (IL-15Ralpha) serves as the specific, high-affinity receptor for IL-15. It is expressed by lymphoid and nonlymphoid cells, including B cell lymphoma lines. In this study, we have further explored IL-15Ralpha-mediated signaling in activated primary B cells and in Raji cells, a human B-lymphoblastoid cell line which expresses the IL-15Ralpha and IL-2Rgamma chains, but lacks the IL-2Rbeta chain. Stimulation of Raji cells with IL-15 induces their proliferation and rescues them from C2-ceramide-induced apoptosis. By immunoprecipitation and Western blotting, we show that treatment of Raji cells and activated primary B cells with IL-15 induces coprecipitation of Syk kinase with the IL-15Ralpha chain. Upon association, the activated Syk kinase phosphorylates the IL-15Ralpha chain as well as phospholipase Cgamma, which coprecipitates with Syk. Furthermore, transfection of Raji cells with stem-loop Syk antisense oligonucleotides prevents IL-15Ralpha and phospholipase Cgamma phosphorylation as well as the inhibition of apoptosis by IL-15. Mutation of a defined region of the intracellular signaling portion of IL-15Ralpha (Tyr227) abrogates both the IL-15Ralpha/Syk association and IL-15Ralpha phosphorylation. Taken together, this suggests that Syk kinase physically and functionally associates with the IL-15Ralpha chain in B cells and that Syk plays a key role in mediating IL-15-induced signal transduction, thus accounting for the distinct functional consequences of IL-15 vs IL-2 binding to B cells.

Apoptosis↗
PubMed2001

Molecular staging of surgical margins after radical prostatectomy by detection of telomerase activity.

BACKGROUND: The further course of prostate cancer (PC) after radical prostatectomy (RPX) is decisively influenced by the local tumor stage. Although it is thus far possible to assess the risk of local recurrence from the pathohistology, precise predictions cannot be made. A more precise evaluation would be desirable, mainly for early planning of adjuvant therapy. Other authors have shown that telomerase activity may be a marker for malignant potential. We assessed the detection of telomerase activity using the telomeric repeat amplification protocol (TRAP) in surgical margins compared to conventional histopathological examination. METHODS: Ninety-two patients with local PC who underwent RPX were examined. After RPX biopsies were obtained from four defined areas of the prostatic fossa and processed by TRAP assay for telomerase activity using a standard protocol. RESULTS: In 5 of 48 patients (10.4%) with organ-confined prostate carcinoma (pT2) telomerase activity could be detected. Seven of 47 patients (14.9%) with locally advanced PC (> pT2) had at least one positive specimen. CONCLUSIONS: The results obtained in our study indicate that detection of telomerase activity by TRAP assay may be a suitable parameter for molecular staging of surgical margins, because of the high tumor-specificity. Further follow-up must clarify whether patients with positive molecular detection have an increased risk of local recurrence.

Biomarkers, Tumor↗
PubMed2001

Structure of the Hodgkin's lymphoma-associated human CD30 gene and the influence of a microsatellite region on its expression in CD30(+) cell lines.

The CD30 antigen is a member of the tumor necrosis factor receptor (TNFR) family which is overexpressed on the surface of the tumor cells of Hodgkin's lymphoma, anaplastic large cell lymphoma (ALCL), and embryonal carcinoma of the testis. In this study the entire cd30 gene which is more than 24000 bp long and organized in eight exons was characterized by analyzing cosmid and phage lambda clones from human placental libraries with long-range polymerase chain reaction (PCR) and sequencing. Differences to other genes of the TNFR family were detected in the region encoding the extracellular domain of the cd30 gene. In nearly all other TNFR genes, the coding region of each cysteine-rich repeat is interrupted by one intron, i.e., the 3-4 cysteine-rich repeats of these receptors are encoded by at least 4-5 exons, whereas the six cysteine-rich repeats of the cd30 gene are encoded by two exons, i.e., each of these exons encode three cysteine-rich repeats. In addition, we also found a genetic polymorphism of tetranucleotide ATCC-repeats in the 5' part of the CD30 promoter. This region was amplified by PCR from seven CD30 overexpressing human lymphoid cell lines and five human tissues with an absent or very low CD30 expression. The amplification products showed length differences of more than 550 bp. The number of the ATCC-repeats was higher in CD30(+) cell lines than in normal tissues. Comparison of the individual PCR products in reporter gene assays revealed that the CD30 promoter activity increased with the length of this polymorphic region up to eightfold. The data suggest that the number of ATCC-repeats in the 5' region of the CD30 promoter modulates the regulation of CD30 expression.

Base Sequence↗
PubMed2001

Association between different attributes of physical activity and fat mass in untrained, endurance- and resistance-trained men.

The objective of this cross-sectional study was to assess different attributes of physical activity and fitness and their relationship to nutritional state in endurance- and resistance-trained, compared to untrained men. The subjects were 42 men matched for age, of which 13 were untrained [UT, mean age 30.2 years, mean height 180.7 cm, mean body mass 83.6 kg, mean body mass index (BMI) 25.6 kg.m-2], 14 were endurance-trained athletes (ET, mean age 29.6 years, mean height 178.4 cm, mean body mass 74.0 kg, mean BMI 23.2 kg.m-2) and 15 were resistance-trained athletes (RT, mean age 28.4 years, mean height 183.4 cm, mean body mass 94.1 kg, mean BMI 27.4 kg.m-2). Fat mass (FM), fat free mass (FFM), muscle mass (MM) and total body water (TBW) were assessed using anthropometry and bioelectrical impedance analysis. Resting energy expenditure was measured by indirect calorimetry (IC) and total energy expenditure (TEE) by a combination of IC and individually calibrated 24-h heart-rate monitoring. The activity related energy expenditure (AEE) and the physical activity level were calculated. Movements were assessed using pedometry. Aerobic fitness was determined using ergometry, muscle strength [quadriceps muscle (Famax), ischiocruralis muscle (Fbmax), biceps muscle (Fcmax), triceps muscle (Fdmax)] by computer tensiometry. Different time domain indexes of heart rate variability (HRV) were examined during sleep, rest and the whole day as an index of sympathetic nervous system (SNS) activity. When compared with UT and RT, ET had reduced body masses and FM, but increased percentage TBW (P < 0.05 and P < 0.01, respectively). FFM and MM were increased in RT, when compared with UT and ET (P < 0.01). ET had higher TEE, AEE, pedometry derived activities, oxygen consumption and power during vigorous exercise than RT and UT (P < 0.05 and P < 0.01, respectively). Respiratory exchange ratio at moderate exercise intensities was increased in RT (P < 0.05). In the 12 time domain indexes of HRV 6 and 10 were higher in ET than in RT and UT respectively (P < 0.05 or P < 0.01, respectively) suggesting an increased SNS activity in ET. By contrast, Famax, Fcmax and Fdmax were elevated in RT (P < 0.01). FM was negatively associated with aerobic fitness, but not with muscle strength. We concluded that the physiological and metabolic adaptations to exercise and nutritional state differ between ET and RT subjects. Participation in RT results predominantly in changes in body composition and strength but not in energy expenditure, movements and SNS activity. The opposite was the case for ET. Aerobic fitness, physical activity, movements and activity of SNS were all increased but body mass and FM were decreased. The latter finding may support the idea that, with regard to possible health benefits, ET is more effective than RT.

Adipose Tissue↗
PubMed2001

Reverse transcriptase-polymerase chain reaction for prostate-specific antigen in the molecular staging of pelvic surgical margins after radical prostatectomy.

OBJECTIVES: To examine the application of reverse transcriptase-polymerase chain reaction (RT-PCR) to assist in prostate-specific antigen (PSA) detection in the surgical margins after radical prostatectomy (RP). The risk of local recurrence increases considerably in the presence of extracapsular tumor growth and/or positive surgical margins at RP. Although this makes it possible to identify patients with an increased risk of local recurrence, precise predictions cannot be made. A more precise assessment is desirable mainly for early planning of adjuvant therapy. METHODS: Ninety-five patients with clinically organ-confined prostate cancer (CaP) underwent RP. After removing the gland, biopsies were obtained from four defined areas of the prostatic fossa and processed for RT-PCR for PSA detection. Sixteen patients with muscle-invasive bladder carcinoma who underwent radical cystoprostatectomy served as controls. RESULTS: Thirty-two of 95 patients with CaP (35%) had at least one positive molecular margin indicating an expression for PSA; 19 of 48 (39%) of these had an organ-confined tumor stage according to conventional histology and 13 of 47 (28%) had tumor growth beyond the prostate. A statistically significant correlation between the frequency of positive molecular margins and clinical data was only observed in the group with disease greater than Stage pT2. All controls had negative molecular margins (P = 0.012). CONCLUSIONS: On the basis of the results obtained, molecular diagnostic RT-PCR for PSA detection in the surgical margins after RP seems to be an interesting supplementary tool for monitoring the course and establishing the prognosis. Long-term follow-up of these patients is needed to demonstrate the clinical value of molecular diagnostics of surgical margins during RP.

Adenocarcinoma↗
PubMed2001

DNA-based detection of prostate cancer in urine after prostatic massage.

OBJECTIVES: Promoter hypermethylation of the glutathione-S-transferase P1 (GSTP1) gene is a specific feature of prostate cancer. This epigenetic DNA alteration served as the target for molecular detection of prostate cancer cells in urine sediments after prostatic massage. METHODS: Bisulfite treatment followed by methylation-specific polymerase chain reaction was used to detect GSTP1 promoter hypermethylation in DNA isolated from urine sediments obtained after prostatic massage of men with and without prostate cancer. RESULTS: GSTP1 promoter hypermethylation was demonstrated in the sediments of 1 (2%) of 45 patients diagnosed with benign prostatic hyperplasia, 2 (29%) of 7 patients with prostatic intraepithelial neoplasia, 15 (68%) of 22 patients with early, intracapsular cancer, and 14 (78%) of 18 patients with locally advanced or systemic prostate cancer, resulting in a specificity of 98% and an overall sensitivity of 73% for the detection of prostate cancer. CONCLUSIONS: Urinalysis for GSTP1 promoter hypermethylation constitutes a sensitive and highly specific DNA-based marker for molecular detection of prostate cancer, including early stages.

Adenocarcinoma↗
PubMed2001

Detection of prostate-specific antigen RNA before and after radical retropubic prostatectomy and transurethral resection of the prostate using "Light-Cycler"-based quantitative real-time polymerase chain reaction.

OBJECTIVES: To report our initial experience gained in establishing real-time reverse transcriptase-polymerase chain reaction (RT-PCR) detection of prostate-specific antigen (PSA) mRNA using the quantitative online PCR system LightCycler. Many studies have thus far failed to provide the desired proof that the detection of circulating PSA-expressing tumor cells with RT-PCR in the blood samples of patients with prostate cancer (PCa) is a highly sensitive prognostic and course marker. One of the possible reasons is the lack of reliable quantification methods. METHODS: Blood samples before and after surgery were obtained from 87 patients who underwent radical prostatectomy for locally confined PCa and 27 patients who underwent transurethral resection of the prostate for benign prostatic hyperplasia. Eight days postoperatively, additional blood samples were obtained from the patients with PCa. Quantitative no-nested RT-PCR for PSA mRNA (291 bp) was performed using the LightCycler system applying the SYBR Green protocol. The number of circulating LNCaP tumor cell-equivalents per sample was estimated from the mean amplification value measured in a given number of LNCaP cells. RESULTS: PSA mRNA was detected preoperatively in 19 patients with Stage pT2 tumor (40%) and in 28 patients with tumor greater than Stage pT2 (72%), but in only 2 patients with benign prostatic hyperplasia (8%; analysis of variance, P <0.001). Significant quantitative differences were observed among Stage pT2 disease (1034 LNCaP tumor cell-equivalents/mL), greater than Stage pT2 disease (7830 cells/mL), and benign prostatic hyperplasia (58 cells/mL; analysis of variance for all groups, P <0.001). The correlation between the detection of PSA expression by RT-PCR and the Gleason score and serum PSA value was statistically significant. CONCLUSIONS: Our results show that the initial experience with the LightCycler system for PSA-assisted detection of circulating PSA mRNA in PCa by RT-PCR may be a promising preoperative prognostic marker for organ-confined or locally advanced PCa. Long-term follow-up of these patients with PCa must demonstrate the clinical value of molecular diagnostics with quantitative RT-PCR systems.

Analysis of Variance↗
PubMed2001

Is TV viewing an index of physical activity and fitness in overweight and normal weight children?

OBJECTIVE: To assess relationships between TV viewing and body composition, energy expenditure, physical activity, fitness and nutrition habits in prepubertal children. DESIGN: Cross-sectional study. SUBJECTS: Sixty prepubertal children (mean body mass index: 20.8 kg m(-2), age: 5-11 years, overweight: n = 52, normal weight: n = 8). METHODS: TV consumption, socio-economic status (SES) and nutrition habits were estimated by questionnaires. Fat mass and fat-free mass were assessed by anthropometrics and bioelectrical impedance analysis, and resting energy expenditure by indirect calorimetry. Total energy expenditure was measured by a combination of indirect calorimetry and individually calibrated 24-hour heart rate (HR) monitoring. Activity-related energy expenditure and physical activity level were calculated. Aerobic fitness (VO2 submax) was determined by ergometry, muscle strength (musculus quadriceps, musculus ischiocruralis) was measured by computer tensiometry. Children were stratified according to their daily TV consumption: 1 h of TV per day (group II). RESULTS: When compared with children of group I, children of group II had increased body weight, body mass index, skinfolds, fat mass and prevalence of overweight (P < 0.05 and <0.01, respectively). By contrast, fat-free mass, energy expenditure, measures of physical activity and muscle strength were similar. Children of group II had normal absolute VO2 submax but reduced adjusted VO2 submax (P < 0.05). They also had parents with a lower educational level (P < 0.05). Similar nutritional habits were observed in both groups. There were no significant differences in the observed parameters between children with high (1-3 h day(-1)) and very high (>3 h day(-1)) TV viewing. CONCLUSIONS: There is a positive relationship between TV viewing and fatness. Increased TV viewing does not reflect reduced 24-hour energy expenditure as assessed by 24-hour HR monitoring, submaximal VO2, muscle strength or poor dietary intake. Increased TV consumption is associated with a low SES.

Body Composition↗
PubMed2001

DNA-based detection of prostate cancer in blood, urine, and ejaculates.

BACKGROUND: Methylation-specific polymerase chain reaction (MSP) targeting promoter hypermethylation of the glutathione S transferase P1 gene (GSTP1), as the most frequent DNA alteration in prostatic carcinoma, was used for the molecular detection of cell-bound and cell-free prostate tumor DNA in various human bodily fluids. MATERIALS AND METHODS: We investigated GSTP1 promoter hypermethylation in DNA isolated from plasma, serum, nucleated blood cells, ejaculates, urines after prostate massage, and prostate tissue from 33 patients with prostate cancer and 26 control patients with benign prostatic hyperplasia (BPH). Using a viral DNA extraction kit specifically recommended for DNA isolation from urine samples, GSTP1 promoter hypermethylation in urine sediments after prostatic massage was investigated in a cohort of 29 patients with prostate cancer and 40 controls with BPH. Fluorescently labeled MSP products were analyzed on an automated gene sequencer. RESULTS: GSTP1 promoter hypermethylation was found in 90% of tumors (18 of 20), 72% of plasma or serum samples (23 of 32), 50% of ejaculates (4 of 8), and between 36% (4 of 11; normal DNA isolation kit) and 76% (22 of 29; viral kit) of exprimated urines from patients with prostate cancer. Also, MSP identified circulating tumor cells in 30% (10 out of 33) of prostate cancer patients. Except for one urine sample, GSTP1 promoter hypermethylation was not found in tissue and body fluids from patients with BPH. CONCLUSION: GSTP1 promoter methylation analysis provides a highly specific tool for DNA-based diagnosis of prostate cancer in body fluids.

Aged↗
PubMed2001

Inducible nitric oxide synthase and glomerular hemodynamics in rats with liver cirrhosis.

This study was designed to test the hypothesis that glomerular de novo expression of inducible nitric oxide synthase (iNOS) contributes to renal hemodynamic abnormalities in liver cirrhosis developed 3 wk after common bile duct ligature (CBDL). De novo expression of iNOS mRNA was detected by RT-PCR in RNA extracts from isolated CBDL rat glomeruli whereas no iNOS mRNA was found in control rat glomerular RNA. Immunohistochemical staining for iNOS was negative in control animals whereas, in CBDL rats, positive iNOS staining was detected in an apparently mesangial pattern in all glomeruli. Western blots of protein extracts from isolated glomeruli of CBDL rats, but not control animals, showed a prominent iNOS band of 130 kDa. Mean arterial pressure (MAP), renal plasma flow (RPF; p-aminohippurate clearance), and glomerular filtration rate (GFR; inulin clearance) were unaltered in CBDL rats, but the application of 4 mg/kg L-N(6)-(1-iminoethyl)lysine, a specific inhibitor of iNOS, reduced GFR and RPF significantly in CBDL rats, whereas control animals were not affected. Similar results were obtained with lipopolysaccharide (LPS)-pretreated animals, which were studied as a positive control for iNOS expression and as a model for recent iNOS induction. We conclude that de novo expression of iNOS occurs in glomeruli of rats with liver cirrhosis and that nitric oxide, generated by iNOS, contributes to the maintenance of glomerular filtration in the early state of this disease.

Animals↗
PubMed2001

Molecular markers in testicular germ cell tumors--objects of clinical research or close to becoming clinical tools?

The aim of this short review is to critically evaluate hitherto investigated molecular markers for testicular germ cell tumors. Molecular parameters have been clinically established as diagnostic and prognostic markers for a number of tumors; this has not yet been achieved for germ cell tumors. There are interesting prospects, however. Studies on the ribonucleoprotein telomerase, for example, have demonstrated a correlation between enzyme activity and chemotherapeutic drug sensitivity. Moreover, innovative treatment approaches target this reverse transcriptase via telomerase antisense RNA. Another potential diagnostic marker is the detection of circulating tumor cells, which correlated with an increased relapse rate in initial studies. There are also interesting possibilities for the germ-cell-tumor-specific isochromosome [i(12)p], which is helpful in the differential diagnosis of mediastinal masses. Here initial studies demonstrated a correlation between the copy number and resistance against chemotherapeutic drugs. Without prospective studies to validate data obtained thus far, neither these nor other parameters can be assessed as diagnostic and prognostic factors. Irrespective of their immediate clinical applicability, however, investigations on molecular alterations in testicular germ cell tumors will become the basis for a molecular-diagnostically oriented subclassification of tumors as well as for novel therapeutic approaches.

Chromosome Aberrations↗
PubMed2001

Increased incidence of luteinizing hormone-releasing hormone receptor gene messenger RNA expression in hormone-refractory human prostate cancers.

There are few options for treating hormone-refractory prostate cancer (PC). Various studies indicate that luteinizing hormone-releasing hormone (LHRH) agonists may have a direct inhibitory effect on prostate tumors mediated by specific LHRH receptors. One study evaluated LHRH receptors in hormone-dependent PC tissue, but no data have thus far been obtained on the presence of LHRH receptors in benign prostatic hyperplasia (BPH) and especially hormone-refractory PC in patients. Thus, it is not yet clear whether LHRH receptors indicate tumor-related differentiation or even hormone-refractory dedifferentiation or are likewise associated with BPH. The aim of this study was to determine the rate of LHRH receptor mRNA expression in BPH and in primary, potentially androgen-dependent and in hormone-refractory PC with clinical progression. Multiplex reverse transcription-PCR was used to simultaneously detect the expression of mRNA for LHRH receptors and beta-actin in 48 patients with BPH, 14 with a primary, possibly hormone-dependent, prostate carcinoma (PPC), and 18 with a hormone-refractory prostate carcinoma (HRPC). Sixteen of 18 samples with HRPC showed intact RNA and expressed mRNA for LHRH receptors (100%). However, the RNA-intact PPC and BPH showed significantly lower expression of mRNA for LHRH receptors (46.2 and 55.3%, respectively; variance analysis: P = 0.0017). The significantly higher expression of mRNA for LHRH receptors in HRPC indicates that therapeutic concepts should be developed that target this site of action. In addition to possible direct effects of LHRH agonists or antagonists demonstrated previously in vitro, it seems useful to apply targeted cytotoxic LHRH analogues or monoclonal antibodies.

Aged↗
PubMed2000

Fluorescent methylation-specific polymerase chain reaction for DNA-based detection of prostate cancer in bodily fluids.

Promoter hypermethylation of the glutathione S-transferase P1 gene (GSTP1) is the most frequent DNA alteration in prostatic carcinoma. Because this epigenetic DNA alteration can be reliably detected by methylation-specific PCR (MSP), we applied this new technique for molecular detection of prostate cancer in various human bodily fluids. We investigated GSTP1 promoter hypermethylation in DNA isolated from plasma, serum, ejaculate, and urine after prostate massage and from prostate carcinoma tissues from 33 patients with prostate cancer and 26 control patients with benign prostatic hyperplasia (BPH). Fluorescently labeled MSP products were analyzed on an automated gene sequencer. Whereas GSTP1 promoter hypermethylation was not detectable by MSP in prostate tissue and bodily fluids from patients with BPH, we found it in 94% of tumors (16 of 17), 72% of plasma or serum samples (23 of 32), 50% of ejaculate (4 of 8) and 36% of urine (4 of 11) from patients with prostate cancer. Additionally, MSP identified circulating tumor cells in 30% (10 of 33) of prostate cancer patients. Analysis of GSTP1 promoter hypermethylation by MSP thus provides a specific tool for molecular diagnosis of prostate cancer in bodily fluids.

Adenocarcinoma↗
PubMed2000

Excitation functions of the analyzing power in pp--> scattering from 0.45 to 2.5 GeV

Excitation functions A(N)(p(p),Theta(c.m.)) of the analyzing power in pp--> elastic scattering have been measured with a polarized atomic hydrogen target for projectile momenta p(p) between 1000 and 3300 MeV/ c. The experiment was performed for scattering angles 30 degrees </=Theta(c.m.)</=90 degrees using the recirculating beam of the proton storage ring COSY during acceleration. The resulting excitation functions and angular distributions of high internal consistency have significant impact on the recent phase shift solution SAID SP99, in particular, on the spin triplet phase shifts between 1000 and 1800 MeV, and demonstrate the limited predictive power of single-energy phase shift solutions at these energies.

Journal Article↗
PubMed2000

The HTLV-I tax protein transcriptionally modulates OX40 antigen expression.

OX40 is a member of the TNF receptor family, expressed on activated T cells. It is the only costimulatory T cell molecule known to be specifically up-regulated in human T cell leukemia virus type-I (HTLV-I)-producing cells. In a T cell line, OX40 surface expression was shown to be induced by HTLV-I Tax alone. To understand molecular mechanisms of OX40 gene regulation and modulation by HTLV-I Tax, we have cloned the human OX40 gene and analyzed its 5'-flanking region. By reporter gene analysis with progressive 5' deletions from nucleotides -1259 to -64, we have defined a 157-bp DNA fragment as a minimal promoter for constitutive expression. In addition, we show that in the OX40+ cell line, Co, Tax is able to further increase OX40 surface expression. Up-regulation of OX40 promoter activity by Tax requires two upstream NF-kappaB sites, which are not active in the constitutive OX40 expression. Their deletion abrogates Tax responsiveness in reporter gene analysis. The site-directed mutagenesis of each NF-kappaB site demonstrates that cooperative NF-kappaB binding is a prerequisite for Tax-directed activity as neither site alone is sufficient for a full Tax responsiveness of the OX40 promoter. Upon Tax expression, both sites bind p65 and c-Rel. These data provide new insight into the direct regulation of OX40 by Tax and add to our understanding of the possible role of the OX40/OX40 ligand system in the proliferation of HTLV-I+ T cells.

Amino Acid Motifs↗
PubMed2000

An interleukin-2-IgG-Fas ligand fusion protein suppresses delayed-type hypersensitivity in mice by triggering apoptosis in activated T cells as a novel strategy for immunosuppression.

BACKGROUND: Cell-mediated immune responses can be down-regulated by induction of apoptosis of immunoreactive lymphocytes. In the present study, we have tested the feasibility of a strategy for immunosuppression by the selective induction of apoptosis in activated, interleukin (IL)-2 receptor-positive lymphocytes, using a triple IL-2-IgG-FasL fusion protein. The IL-2-IgG-FasL fusion protein combines IL-2 for the selection of activated T cells, with the extracellular domain of the FasL molecule for inducing T-cell apoptosis. These components were separated by the Fc part of IgG1 serving as a spacer as well as for half-life prolongation. METHODS: The gene for the chimeric protein was created by fusing DNA sequences encoding for the three functional components: human IL-2, the Fc part of human IgG1, and the extracellular domain of murine FasL. When the fusion gene was expressed in murine J558L cells, we obtained soluble dimeric immunoglobulin-like proteins in the supernatant. After analyzing the function of the IL-2 and FasL portions individually in vitro, a delayed-type hypersensitivity (DTH) reaction to sheep red blood cells as model for cell-mediated immune responses was investigated to evaluate the IL-2-IgG-FasL-mediated immunosuppression in vivo. RESULTS: In vitro, the IL-2-IgG-FasL fusion protein supported IL-2-dependent proliferation of Fas-resistant CTLL-2 cells, whereas concanavalin A-T blasts were induced to undergo apoptosis by the FasL portion. In vivo, this fusion protein potently inhibited a murine DTH. This was associated with an increased rate of apoptosis in activated lymphocytes in the spleen, even at very low doses of the fusion protein. Furthermore, a second antigen challenge 10 days after IL-2-IgG-FasL treatment still failed to elicit a DTH response. CONCLUSION: The abrogation of a standard T cell-dependent immune response in vivo demonstrates that IL-2-IgG-FasL can be successfully exploited to trigger the death of deleterious T cells, presenting a potentially useful strategy in the management of autoimmune diseases and allotransplant rejections.

Animals↗