Directed mutagenesis of apecific active site residues on Fibrobacter succinogenes 1,3-1,4-beta -D-glucanase significantly affects catalysis and enzyme structural stability

The functional and structural significance of amino acid residues Met(39), Glu(56), Asp(58), Glu(60), and Gly(63) of Fibrobacter succinogenes 1,3-1,4-beta-d-glucanase was explored by the approach of site-directed mutagenesis, initial rate kinetics, fluorescence spectroscopy, and CD spectrometry. Glu(56), Asp(58), Glu(60), and Gly(63) residues are conserved among known primary sequences of the bacterial and fungal enzymes. Kinetic analyses revealed that 240-, 540-, 570-, and 880-fold decreases in k(cat) were observed for the E56D, E60D, D58N, and D58E mutant enzymes, respectively, with a similar substrate affinity relative to the wild type enzyme. In contrast, no detectable enzymatic activity was observed for the E56A, E56Q, D58A, E60A, and E60Q mutants. These results indicated that the carboxyl side chain at positions 56 and 60 is mandatory for enzyme catalysis. M39F, unlike the other mutants, exhibited a 5-fold increase in K(m) value. Lower thermostability was found with the G63A mutant when compared with wild type or other mutant forms of F. succinogenes 1,3-1,4-beta-d-glucanase. Denatured wild type and mutant enzymes were, however, recoverable as active enzymes when 8 m urea was employed as the denaturant. Structural modeling and kinetic studies suggest that Glu(56), Asp(58), and Glu(60) residues apparently play important role(s) in the catalysis of F. succinogenes 1,3-1,4-beta-d-glucanase.

Endothelin-1 stimulates leptin production in adipocytes

Leptin is an adipocyte-derived hormone that regulates body fat stores and feeding behavior. In an effort to identify endogenous diffusible modulators of leptin production, we found that endothelin-1 (ET-1) up-regulates leptin expression in adipocytes. ET-1 is as potent and efficacious as insulin in stimulating leptin production in two different adipocyte cell lines. Endothelins stimulate leptin production via the endothelin-A receptor (ET(A)), as judged by a potency rank order of ET-1 ET-3. We detected expression of ET(A) but not ET(B) in both cell lines by Northern blot analysis. In addition, the ET(A)-selective antagonist FR139317 inhibited ET-1-induced leptin expression more potently than did the ET(B)-selective antagonist BQ788. ET-1 and insulin positively interact with each other in increasing leptin production in adipocytes. In primary mouse white fat cells, we detected expression of both ET(A) and ET(B) by Northern blot and in situ hybridization analyses. We conclude that ET-1 stimulates leptin production via the ET(A) receptor in cultured adipocytes.

Adsorption of cadmium on biosolids-amended soils

Debate exists over the biosolid phase (organic or inorganic) responsible for the reduction in phytoavailable Cd in soils amended with biosolids as compared with soils amended with inorganic salts. To test the importance of these two phases, adsorption isotherms were developed for soil samples (nine biosolids-amended soils and their five companion controls) and two biosolids samples from five experimental sites with documented histories of biosolids application. Subsamples were treated with 0.7 M NaClO to remove organic carbon. Cadmium nitrate was added to both moist soil samples and their soil inorganic fractions (SIF) in a 0.01 M Ca(NO3)2 solution at three pH levels (6.5, 5.5, and 4.5), and equilibrated at 22 +/- 1 degrees C for at least 48 h. Isotherms of Cd adsorption for biosolids-amended soil were intermediate to the control soil and biosolids. Decreasing pH did not remove the difference between these isotherms, although adsorption of Cd decreased with decreasing pH level. Organic matter removal reduced Cd adsorption on all soils but had little influence on the observed difference between biosolids-amended and control soils. Thus, increased adsorption associated with biosolids application was not limited to the organic matter addition from biosolids; rather, the biosolids application also altered the adsorptive properties of the SIF. The greater affinity of the inorganic fraction of biosolids-amended soils to adsorb Cd suggests that the increased retention of Cd on biosolids-amended soils is independent of the added organic matter and of a persistent nature.

Argatroban: a direct thrombin inhibitor for heparin-induced thrombocytopenia and other clinical applications

Argatroban, a direct thrombin inhibitor derived from arginine, is an effective anticoagulant indicated for prophylaxis or treatment of thrombosis in patients with heparin-induced thrombocytopenia (HIT). Argatroban has been used as an alternative anticoagulant in patients with HIT in various clinical conditions including interventional cardiovascular procedures that require anticoagulation. Satisfactory clinical outcomes with acceptable complications have been reported in these patients. Whether argatroban offers additional clinical advantage over conventional heparin therapy in patients without HIT remains unclear. Argatroban has been evaluated as an alternative anticoagulant to replace heparin in various clinical studies, especially in patients with coronary artery disease or cerebral vascular disease. To date, it remains unclear if argatroban is more effective than heparin, although the agent seems to cause less bleeding complications. This article reviews the pharmacology of argatroban and its clinical application beyond the management of HIT, with particular emphasis on interventional cardiology procedure, acute myocardial infarction, unstable angina pectoris, cerebral thrombosis or ischemic stroke, peripheral obstructive arterial disease, and extracorporeal circulation.

A genome-wide search for type II diabetes susceptibility genes in Chinese Hans

AIMS/HYPOTHESIS

The aim of the study was to search for Type II (non-insulin-dependent) diabetes mellitus susceptibility genes in a Chinese population.

METHODS

A genome-wide scan was carried out using non-parametric linkage analyses. We studied 102 families (478 family members) who were Chinese Hans residing in east and south-east China, including 282 diabetic patients, among them 142 independent affected sibpairs were available for genotyping. A total of 247 fluorescence labelled microsatellite markers, with an average resolution of 15 cM, were amplified. GENEHUNTER was used for the non-parametric linkage analyses.

RESULTS

Two loci on chromosome 9 D9S171 and D9S175 showed suggestive evidence for linkage, with an NPL-score of 3.286 and 2.939 respectively, and a p value of 1.19 x 10(-4) and 4.47 x 10(-4). A locus on the long arm of chromosome 20, D20S196 showed a rise in the non-parametric-linkage score (from 1.517 to 2.922) and a corresponding decrease in the p value from 0.04 to 6.5 x 10(-4) when families with lower BMI were analysed alone. Other loci with weaker evidence for linkage were also observed.

CONCLUSIONS

Our results suggest that chromosome 9 contains genes involved in the susceptibility to Type II diabetes in an eastern and southeastern Chinese Han population, and chromosome 20 could hide genes linked to Type II diabetes in families with a lower BMI. Other regions could also hide susceptibility genes with minor effects.

Intracranial bone marrow transplantation after traumatic brain injury improving functional outcome in adult rats

OBJECT

The authors tested the hypothesis that intracranial bone marrow (BM) transplantation after traumatic brain injury (TBI) in rats provides therapeutic benefit.

METHODS

Sixty-six adult Wistar rats, weighing 275 to 350 g each, were used for the experiment. Bone marrow prelabeled with bromodeoxyuridine (BrdU) was harvested from tibias and femurs of healthy adult rats. Other animals were subjected to controlled cortical impact, and BM was injected adjacent to the contusion 24 hours after the impact. The animals were killed at 4, 7, 14, or 28 days after transplantation. Motor function was evaluated both before and after the injury by using the rotarod test. After the animals had been killed, brain sections were examined using hemotoxylin and eosin and immunohistochemical staining methods. Histological examination revealed that, after transplantation, BM cells survived, proliferated, and migrated toward the injury site. Some of the BrdU-labeled BM cells were reactive, with astrocytic (glial fibrillary acid protein) and neuronal (NeuN and microtubule-associated protein) markers. Transplanted BM expressed proteins phenotypical of intrinsic brain cells, that is, neurons and astrocytes. A statistically significant improvement in motor function in rats that underwent BM transplantation, compared with control rats, was detected at 14 and 28 days posttransplantation.

CONCLUSIONS

On the basis of their findings, the authors assert that BM transplantation improves neurological outcome and that BM cells survive and express nerve cell proteins after TBI.

Human CD1d-glycolipid tetramers generated by in vitro oxidative refolding chromatography

CD1 molecules are specialized in presenting lipids to T lymphocytes, but identification and isolation of CD1-restricted lipid specific T cells has been hampered by the lack of reliable and sensitive techniques. We here report the construction of CD1d-glycolipid tetramers from fully denatured human CD1d molecules by using the technique of oxidative refolding chromatography. We demonstrate that chaperone- and foldase-assisted refolding of denatured CD1d molecules and beta(2)-microglobulin in the presence of synthetic lipids is a rapid method for the generation of functional and specific CD1d tetramers, which unlike previously published protocols ensures isolation of CD1d tetramers loaded with a single lipid species. The use of human CD1d-alpha-galactosylceramide tetramers for ex vivo staining of peripheral blood lymphocytes and intrahepatic T cells from patients with viral liver cirrhosis allowed for the first time simultaneous analysis of frequency and specificity of natural killer T cells in human clinical samples. Application of this protocol to other members of the CD1 family will provide powerful tools to investigate lipid-specific T cell immune responses in health and in disease.

[The advancement of G protein and coupled signal transduction pathways]

G protein coupled signal transduction system is one major transmembrane signaling pathways in cell. Research of biochemistry and pharmacology in medicine showed that a lot of medicines play their role through G protein coupled signaling pathways. Thus, systematic study on G protein structure and functions had very important effects on new medicine producing. In the process of creature evolution, there are highly conserved amino-acid sequences in G protein. Study on G protein and coupled signal components in plants and insects signaling processes may benefit to determine the mechanism of crop resistance to disease and pest insect and resistant chemicals effect on insect behavior and physiology. This paper reviews the research progress and prospect of practical use in recent studies of G protein and coupled components in animal, insect and plant signaling pathways.

A novel method to 'exercise' rats: making rats rise to erect bipedal stance for feeding - raised cage model

We employed a novel method to exercise rats: making them rise to bipedal stance for feeding using raised cages. We studied its effects on the skeletons of 6 and 10-month-old intact or orchidectomized (ORX) rats. Body and hindlimb muscle weights, tibial BMC and periosteal cortical bone formation increased after housing in raised cages, but more so in 6-month-old animals than in 10-month-old ones. In 6-month-old orchidectomized rats, raised cages partially prevented ORX-induced bone loss by stimulating periosteal cortical bone (TX) formation and decreased bone resorption next to marrow. In 10-month-old male orchidectomized rats, raised cages also decreased the endosteal and trabecular bone resorption, but not enough to prevent completely ORX-induced net bone losses. Because the osteogenic effects of raised cages alone were only partial, we also studied the interaction between raised cage and prostaglandin E(2) (PGE(2)) in 10-month-old retired female breeders. When treated with combined raised cage and PGE(2), both cortical (TX) and trabecular bone mass of the proximal tibial metaphysis and lumbar vertebral body increased over either raised cages or PGE(2) treatment alone, that was accompanied by dramatic increased bone formation at periosteal and endosteal surfaces. Thus making rats rise to erect bipedal stance for feeding helps to prevent bone loss after orchidectomy; it amplifies the anabolic effects of PGE(2), and it provides an inexpensive, non-invasive and reliable way to increase mechanical loading of certain bones of the rat skeleton.

The capture envelope of a flanged circular hood in cross drafts

The flow patterns of an exterior circular hood subject to the influence of various uniform cross drafts were experimentally studied in an apparatus consisting of hood-model/wind-tunnel assembly. A two-component laser Doppler anemometer was employed to measure the velocity field on the symmetry plane. The streamline patterns were obtained from the measured velocity data. The cross draft caused a characteristic envelope similar to a half Rankine body-of-revolution to form in the flow field. The boundary of the envelope is described by a dividing streamline. All streamlines within the envelope lead to the opening; those outside the envelope evolve to the downstream area. The normalized geometry of the capture envelope is theoretically justified and correlated by modifying the potential theory of point-sink-plus-rectilinear-flow. The domain and shape of the envelope enclosing the hood opening are determined primarily by the velocity ratio between the cross draft and hood suction. The correlated formula is applicable to design the hood parameters, including the sizes of opening and flange as well as the location of contaminant sources.

The lipophilicity, pharmacokinetics, and cellular uptake of different chemically-modified tetracyclines (CMTs)

CMTs are analogs of tetracyclines, which are chemically modified to eliminate their antimicrobial efficacy but which retain their inhibitory activity against matrix metalloproteinases. These compounds have been found to inhibit connective tissue breakdown in animal models of diseases such as periodontitis, arthritis and cancer. Because CMTs exhibit different in vivo efficacy in these various models of disease, the current study compared their pharmacokinetics and other properties as follows: Adult male Sprague-Dawley rats were administered by oral gavage a single dose of 5mg of different CMTs suspended in 1 ml 2% carboxymethyl-cellulose, and blood samples were collected from 1-48 hours after dosing. The sera were extracted, then analyzed by HPLC using a C-18 reverse-phase column. The results showed that the peak concentrations (C(max)) in rat sera 1-12 hours after oral administration of CMTs -1, -2,-3, -4,-5,-6,-7,-8 and doxycycline were 5.5, 0.7, 4.6, 6.2, 0.8, 0.7, 9.0 (note: the 3 peaks detected for CMT-7 were combined), 15.0 and 0.9 microg/ml, respectively. Their in vivo half-lives (t(1/2)) were 11, 5, 22, 11, 32, 15, 37, 38, and 17 hours, respectively. Of the anticollagenase CMTs tested, CMT-8 showed the greatest C(max) and t(1/2)values, followed by CMTs-3, -1, -4, and perhaps -7; CMTs-2, -5, and -6 exhibited much lower levels in serum. The relative lipophilicities of the 8 CMTs and doxycycline were tested by examining their extractability in octanol. The results showed that CMT-2, -5, and -6 had the lowest partition coefficients using this organic solvent, while CMT-3 was the most lipophilic. The lipophilicity of the different CMTs was also positively correlated (r(2)=0.767, P<0.05) to peak serum concentrations (C(max)), but not to their serum half-lives (r(2)=0.25,P=0.49). This property of the different CMTs was also found to be positively correlated to their ability to enter into human whole blood cells in vitro (r2=0.95, P<0.001). Since CMT-8, as well as CMTs-3 and -1, consistently exhibited the greatest in vivo efficacy in animal models of tissue breakdown, this may reflect, at least in part, their favorable pharmacokinetics and tissue uptake.

Delivery of biological performance via micro-encapsulation formulation chemistry

Lambda-cyhalothrin micro-capsules have been prepared by a novel in situ procedure. Manipulation of the chemistry has led to slow- and fast-release formulations. The latter has a biological performance comparable to commercial lambda-cyhalothrin emulsifiable concentrates, but exhibits a significantly improved toxicological profile over EC, WP and WG formulations. Micro-encapsulation technology satisfies many of the drivers towards the safer use of pesticides.

Transcription of Epstein-Barr virus-encoded nuclear antigen 1 promoter Qp is repressed by transforming growth factor-beta via Smad4 binding element in human BL cells

In Epstein-Barr virus (EBV)-infected BL cells, the oncogenic EBV-encoded nuclear antigen 1 (EBNA 1) gene is directed from the latent promoter Qp. Yeast one-hybrid screen analysis using the -50 to -37 sequence of Qp as the bait was carried out to identify transcriptional factors that may control Qp activity. Results showed that Smad4 binds the -50 to -37 sequence of Qp, indicating that this promoter is potentially regulated by TGF-beta. The association of Smad4 with Qp was further confirmed by supershift of EMSA complexes using Smad4-specific antibody. The transfection of a Qp reporter construct in two EBV(+) BL cell lines, Rael and WW2, showed that Qp activity is repressed in response to the TGF-beta treatment. This repression involves the interaction of a Smad3/Smad4 complex and the transcriptional repressor TGIF, as determined by cotransfection assay and coimmunoprecipitation analysis. Results suggest that TGF-beta may transcriptionally repress Qp through the Smad4-binding site in human BL cells.

Stress analysis of different wall thicknesses of implant fixture with various boundary levels

The aim of the present work is to develop 3D finite element models of implant fixture with different wall thicknesses to predict maximum stress concentration sites and distribution contours after loading. A maximum lateral force of 150 N was applied to simulate horizontal occlusal forces. When the fixtures were constrained to simulate different boundary levels, the maximum equivalent stress (max EQV) was always located at the implant-bone interface. Max EQV increased when the wall thickness or boundary level was reduced to a certain extent. The fixture with a wall thickness of 0.97 mm demonstrated the smallest stress increase ratio when the boundary level was lowered. Our results indicated that both wall thickness and the boundary level played important roles in maintaining a well-distributed stress level within the fixture. The stress concentration decreased when the fixture wall became thicker, however, this effect was less significant when the surrounding bone level was reduced.

Novel antihyperglycemic terpenoid-quinones from Pycnanthus angolensis

Two new compounds, pycnanthuquinone A (1) and pycnanthuquinone B (2), were isolated from leaves and stems of the African plant, Pycnanthus angolensis (Welw.) Warb (Myristicaceae), by bioassay-guided fractionation of an ethanolic extract using a diabetic mouse model. Pycnanthuquinones A and B are the first representatives of a novel terpenoid-type quinone skeleton, and both compounds possess significant antihyperglycemic activity.

Anaerobic stability of aqueous physostigmine solution

The anaerobic stability of physostigmine was studied in this report. Physostigmine and two important degradants, eseroline and rubreserine, were identified by a high-performance liquid chromatography (HPLC) system using a photodiode array detector and a UV detector at the retention times of 12.4, 9.2, and 7.9 min. Under anaerobic treatment, the minimum degradation rate constant was found at pH 3.4, evaluating from pH-rate profiles at 45 degrees C, 55 degrees C, and 70 degrees C with the pH range 2.4-6.8. The degradation of physostigmine was suggested as specific acid-base catalysis. Anaerobic activation energies of KH, K(OH), and Kobs were 9.4, 8.3, and 17.9 kcal/mol, respectively. The ratios of observed aerobic and anaerobic rate constants were 2-33 at 88 degrees C, which had a trend to increase ratios as pH increased in the range 2.4-5.2. The shelf life of physostigmine solution was estimated to be 4 years at room temperature under anaerobic conditions at pH 3.4.

Gene expression profiling in the human hypothalamus-pituitary-adrenal axis and full-length cDNA cloning

The primary neuroendocrine interface, hypothalamus and pituitary, together with adrenals, constitute the major axis responsible for the maintenance of homeostasis and the response to the perturbations in the environment. The gene expression profiling in the human hypothalamus-pituitary-adrenal axis was catalogued by generating a large amount of expressed sequence tags (ESTs), followed by bioinformatics analysis (http://www.chgc.sh.cn/ database). Totally, 25,973 sequences of good quality were obtained from 31,130 clones (83.4%) from cDNA libraries of the hypothalamus, pituitary, and adrenal glands. After eliminating 5,347 sequences corresponding to repetitive elements and mtDNA, 20,626 ESTs could be assembled into 9, 175 clusters (3,979, 3,074, and 4,116 clusters in hypothalamus, pituitary, and adrenal glands, respectively) when overlapping ESTs were integrated. Of these clusters, 2,777 (30.3%) corresponded to known genes, 4,165 (44.8%) to dbESTs, and 2,233 (24.3%) to novel ESTs. The gene expression profiles reflected well the functional characteristics of the three levels in the hypothalamus-pituitary-adrenal axis, because most of the 20 genes with highest expression showed statistical difference in terms of tissue distribution, including a group of tissue-specific functional markers. Meanwhile, some findings were made with regard to the physiology of the axis, and 200 full-length cDNAs of novel genes were cloned and sequenced. All of these data may contribute to the understanding of the neuroendocrine regulation of human life.

Identification of NY-ESO-1 peptide analogues capable of improved stimulation of tumor-reactive CTL

Expression of NY-ESO-1 in a high proportion of different human tumors makes this protein a very attractive vaccine target. NY-ESO-1 peptides, recognized by HLA-A2-restricted CTL, have recently been described. However, it remains unclear how efficiently tumors generate these epitopes, and whether peptide analogues can be used for optimal expansion and activation of NY-ESO-1-specific HLA-A2-restricted CTL. By generating unique CTL clones, we demonstrate that NY-ESO-1-positive tumor cells are efficiently killed by HLA-A2-restricted CTL specific for the peptide epitope NY-ESO-1 157-165. Presentation of this epitope is not affected by the presence or absence of the proteasome subunits low molecular proteins 2 and 7 and is not blocked by proteasome inhibitors, while it is impaired in the TAP-deficient cell line LBL 721.174. NY-ESO-1 157-165 peptide analogues were compared for their antigenicity and immunogenicity using PBL from melanoma patients. Three peptides, containing the carboxyl-terminal cysteine substituted for either valine, isoleucine, or leucine, were recognized at least 100 times more efficiently than the wild-type peptide by specific CTL. Peptide analogues were capable of stimulating the expansion of NY-ESO-1-specific CTL from PBL of melanoma patients much more efficiently than wild-type peptide. These findings define the processing requirements for the generation of the NY-ESO-1 157-165 epitope. Identification of highly antigenic NY-ESO-1 peptide analogues may be important for the development of vaccines capable of expanding NY-ESO-1-specific CTL in cancer patients.

Phase I study in melanoma patients of a vaccine with peptide-pulsed dendritic cells generated in vitro from CD34(+) hematopoietic progenitor cells

Dendritic cells (DCs) are professional antigen-presenting cells (APCs) that can be used for vaccination purposes, to induce a specific T-cell response in vivo against melanoma-associated antigens. We have shown that the sequential use of early-acting hematopoietic growth factors, stem cell factor, IL-3 and IL-6, followed by differentiation with IL-4 and granulocyte-macrophage colony-stimulating factor allows the in vitro generation of large numbers of immature DCs from CD34(+) peripheral blood progenitor cells. Maturation to interdigitating DCs could specifically be induced within 24 hr by addition of TNF-alpha. Here, we report on a phase I clinical vaccination trial in melanoma patients using peptide-pulsed DCs. Fourteen HLA-A1(+) or HLA-A2(+) patients received at least 4 i.v. infusions of 5 x 10(6) to 5 x 10(7) DCs pulsed with a pool of peptides including either MAGE-1, MAGE-3 (HLA-A1) or Melan-A, gp100, tyrosinase (HLA-A2), depending on the HLA haplotype. A total of 83 vaccinations were performed. Clinical side effects were mild and consisted of low-grade fever (WHO grade I-II). Clinical and immunological responses consisted of anti-tumor responses in 2 patients, increased melanoma peptide-specific delayed-type hypersensitivity reactions in 4 patients, significant expansion of Melan-A- and gp100-specific cytotoxic T lymphocytes in the peripheral blood lymphocytes of 1 patient after vaccination and development of vitiligo in another HLA-A2(+) patient. Our data indicate that the vaccination of peptide-pulsed DCs is capable of inducing clinical and systemic tumor-specific immune responses without provoking major side effects.

[A study on the chemical components of essential oil of oak moss concrete by gas chromatography/mass spectrometry]

The essential oil of oak moss concrete was extracted by volatile oil content equipment. The chemical compositions and their relative contents were analyzed by GC and GC/MS. A Supelco-5 fused silica capillary column (30 m x 0.32 mm i.d.; 0.25 micron thickness) and a flame ionization detector (FID) were employed in GC analysis. The temperature program included temperature increase of 4 degrees C/min from 50 degrees C to 250 degrees C, and a 10 min isothermal period at 250 degrees C. Mass spectra were obtained by electron impact at 70 eV and a source temperature of 170 degrees C. Twenty-four volatile compounds of oak mass concrete were identified, which comprised more than 83% of volatile fraction. The major components were diethyl phthalate, alpha-terpineol, cedrane and linalool.

Phase I study in melanoma patients of a vaccine with peptide-pulsed dendritic cells generated in vitro from CD34(+) hematopoietic progenitor cells

Dendritic cells (DCs) are professional antigen-presenting cells (APCs) that can be used for vaccination purposes, to induce a specific T-cell response in vivo against melanoma-associated antigens. We have shown that the sequential use of early-acting hematopoietic growth factors, stem cell factor, IL-3 and IL-6, followed by differentiation with IL-4 and granulocyte-macrophage colony-stimulating factor allows the in vitro generation of large numbers of immature DCs from CD34(+) peripheral blood progenitor cells. Maturation to interdigitating DCs could specifically be induced within 24 hr by addition of TNF-alpha. Here, we report on a phase I clinical vaccination trial in melanoma patients using peptide-pulsed DCs. Fourteen HLA-A1(+) or HLA-A2(+) patients received at least 4 i.v. infusions of 5 x 10(6) to 5 x 10(7) DCs pulsed with a pool of peptides including either MAGE-1, MAGE-3 (HLA-A1) or Melan-A, gp100, tyrosinase (HLA-A2), depending on the HLA haplotype. A total of 83 vaccinations were performed. Clinical side effects were mild and consisted of low-grade fever (WHO grade I-II). Clinical and immunological responses consisted of anti-tumor responses in 2 patients, increased melanoma peptide-specific delayed-type hypersensitivity reactions in 4 patients, significant expansion of Melan-A- and gp100-specific cytotoxic T lymphocytes in the peripheral blood lymphocytes of 1 patient after vaccination and development of vitiligo in another HLA-A2(+) patient. Our data indicate that the vaccination of peptide-pulsed DCs is capable of inducing clinical and systemic tumor-specific immune responses without provoking major side effects.

Generation and purification of CD8+ melan-A-specific cytotoxic T lymphocytes for adoptive transfer in tumor immunotherapy

Tumor antigens that might serve as potential targets for adoptive T-cell therapy have been defined in different tumor entities, especially in malignant melanoma. To generate conditions to induce primary T-cell responses against different HLA-A*0201-restricted melanoma peptides and to allow further expansion of peptide-specific T cells for adoptive transfer, CD8+-purified T cells from healthy donors were stimulated with Melan-A-pulsed autologous dendritic cells. Dendritic cells were generated in vitro from monocytes with granulocyte macrophage colony-stimulating factor, interleukin-4, and transforming growth factor-beta1. After 3-4 weekly stimulation cycles with Melan-A-pulsed DCs, we were able to induce a strong peptide-specific CTL response in vitro. MHC-peptide tetramer staining revealed a frequency of up to 3.5% CD8+/Melan-A+ T cells. Additional antigen-independent expansion with anti-CD3/anti-CD28 monoclonal antibodies together with interleukin-2 gave rise to 600-fold expansion of CD8+ CTLs that maintained Melan-A specificity and were able to efficiently lyse Melan-A-expressing melanoma cells. To enrich antigen-specific T cells in vitro, we used a recently established technology for analysis and sorting of live cells according to secreted cytokines. In the present study, we demonstrated that Melan-A-specific T cells can be purified by magnetic separation according to secreted IFN-gamma. These cells revealed a very potent monospecific CTL response, even at low E:T ratios, against Melan-A-pulsed and Melan-A-expressing target cells. Altogether, our study demonstrated that we have developed an efficient method for generating large numbers of peptide-specific T cells in vitro that may be used for adoptive T-cell transfer in tumor immunotherapy.