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At least 397 records · Page 22Linked to original sources

Adoptive transfer of chimeric FcepsilonRI gene-modified human T cells for cancer immunotherapy.

Immunotherapeutic approaches involving genetic modification of T cells show promise in generating highly specific tumor-reactive effector cells for cancer treatment. Given the high affinity of FcRI (the subtype I Fc receptor for IgE) for IgE monoclonal antibody (mAb), modification of T cells with chimeric FcRI in combination with tumor-specific IgE mAbs is potentially a powerful and effective strategy to specifically target T cells to tumor cells. In this study, we retrovirally transduce human primary T cells with a cDNA encoding the extracellular domain of FcRI linked to the hinge and transmembrane domains of FcRI and the cytoplasmic domains of CD28 and T cell receptor zeta chain (FcRI-CD28-zeta). We demonstrate that human T cells expressing FcRI-CD28-zeta, in the presence of tumor-specific IgE mAb recognizing mouse CD8 antigen (Ly- 2.1+), can specifically secrete cytokine, proliferate, and mediate cytotoxic function after antigen ligation. Furthermore, adoptive transfer of FcRI-CD28-zeta cells incubated with anti-Ly-2.1 IgE mAb significantly enhances the survival of irradiated nonobese diabetic-severe combined immunodeficiency mice bearing Ly-2.1+ tumor compared with control mice. Thus, this set of experiments demonstrates that Fc gene-engineered human T cells mediate effector function in vitro and in vivo in an IgE-dependent manner and thus a novel and valid approach for cancer therapy can now be further developed.

Adoptive Transfer↗

DNASUN: a package of computer programs for the biotechnology laboratory.

The paper describes a new software package DNASUN developed for supporting gene engineering laboratories. The package provides a user-friendly interface for experimental researches and supports the traditional nucleotide/protein sequence analysis as well as physical mapping, sequencing, plasmid manipulations, optimal oligonucleotide probe selection and other common molecular biology procedures.

Biotechnology↗

Internet resources for phenotyping engineered rodents.

Genetically engineered mice (GEM) and rats (GER) have emerged as the main mammalian models for investigating normal (physiological, or "health") and abnormal (patho-logical, or "disease") mechanisms. Regardless of the genetic manipulation, novel GEM and GER must undergo meticulous genotypic and phenotypic analyses before it is possible to predict the significance of the engineered gene with re-spect to health and disease, especially when the desire is to extrapolate the findings to humans. Numerous websites have been generated to give researchers additional tools to facilitate genotyping and phenotyping. This list of many extant sites with descriptions of their basic features provides a starting point for new and established scientists faced with the need to characterize a new GEM or GER model.

Animals↗

Soluble human high-affinity receptor for IgE abrogates the IgE-mediated allergic reaction.

The high-affinity receptor for IgE (Fc epsilon RI) has a tetrameric structure structure composed of one alpha, one beta, and two disulfide-linked gamma subunits, of which the alpha subunit binds IgE with high affinity. A recombinant soluble form of the ectodomain of the human Fc epsilon RI alpha subunit (rsFc epsilon RI alpha) was recently generated by gene engineering and was verified to bind IgE with an affinity as high as that of native Fc epsilon RI on the cell surface. rsFc epsilon RI alpha was prepared on a large scale in order to analyze its biological function. rsFc epsilon RI alpha completely inhibited IgE binding to the cell surface, resulting in abrogation of the chemical mediator release from RBL-2H3 cells. Furthermore it completely abolished the passive cutaneous anaphylaxis (PCA) response by trapping IgE specifically when it was administered into rats prior to IgE sensitization. Even after IgE sensitization, treatment of rsFc epsilon RI alpha substantially reduced the PCA response. It was finally shown that rsFc epsilon RI alpha inhibited IgE binding to human peripheral blood basophils and the histamine release from them. In this paper we address the ability of rsFc epsilon RI alpha to specifically prevent the IgE-mediated allergic reaction.

Animals↗

In vivo excision and amplification of large segments of the Escherichia coli genome.

In vivo excision and amplification of large segments of a genome offer an alternative to heterologous DNA cloning. By obtaining predetermined fragments of the chromosome directly from the original organism, the problems of clone stability and clone identification are alleviated. This approach involves the insertion of two recognition sequences for a site-specific recombinase into the genome at predetermined sites, 50-100 kb apart. The integration of these sequences, together with a conditional replication origin (ori), is targeted by homologous recombination. The strain carrying the insertions is stably maintained until, upon induction of specifically engineered genes, the host cell expresses the site-specific recombinase and an ori-specific replication protein. The recombinase then excises and circularizes the genomic segment flanked by the two insertions. This excised DNA, which contains ori, is amplified with the aid of the replication protein and can be isolated as a large plasmid. The feasibility of such an approach is demonstrated here for E. coli. Using the yeast FLP/FRT site-specific recombination system and the pi/gamma-ori replication initiation of plasmid R6K, we have devised a procedure that should allow the isolation of virtually any segment of the E. coli genome. This was shown by excising, amplifying and isolating the 51-kb lacZ--phoB and the 110-kb dapX--dsdC region of the E. coli MG1655 genome.

Antiporters↗

Requirement of different subdomains of calpastatin for calpain inhibition and for binding to calmodulin-like domains.

Calpain requires Ca2+ for both proteolysis of its substrates and interaction with its endogenous inhibitor, calpastatin. The mechanism of inhibition of calpain by calpastatin has remained unsolved, although Nishimura and Goll [J. Biol. Chem. 266, 11842-11850 (1991)] reported that autolyzed calpain fragments containing calmodulin-like domains (CaMLDs) bound to an immobilized calpastatin column. We investigated the correlation between CaMLD-binding and calpain inhibition using immobilized columns of gene-engineered CaMLDs derived from the human mu-calpain large subunit and various recombinant calpastatin mutants. Among the four internally repetitive inhibitory domains of calpastatin, each having conserved regions A, B, and C, only domains 1 and 4 showed the binding activity. The region B deletion mutant of domain 1, retaining the CaMLD-binding ability, no longer had the calpain inhibition activity, and became susceptible to proteolysis. In contrast, a synthetic oligopeptide of region B with moderate calpain inhibition activity did not bind to the column. Domain 3 acquired the binding ability on substitution of region A with that of domain 1. These results suggest that calpain inhibition and binding to the CaMLDs are not correlated or mediated by different subdomains of calpastatin.

Amino Acid Sequence↗

Expression of mouse immunoglobulin light and heavy chain variable regions in Escherichia coli and reconstitution of antigen-binding activity.

The expression of immunoglobulin heavy and light chain variable regions in the cytoplasm of Escherichia coli and formation of a functional heterodimer has been demonstrated. Variable domain sequences were taken from the heavy and light chain cDNAs of the monoclonal antibody Gloop 2 and engineered for expression in a dual origin expression vector. The engineered genes vhg2 and vlg2 were separately subcloned into the vector, creating two expression plasmids. Expression of the heavy and light chain variable region genes (encoding 116 and 109 amino acids respectively) was investigated in eight E. coli strains; the polypeptides were rapidly degraded in a host strain optimized for expression and in E. coli strains deficient in the major protease La (lon-). Accumulation was permitted in severely protease-deficient E. coli having a defective heat-shock response. A lon- mutation in this genetic background permitted even higher accumulation. Expression levels were 7 and 1% of total bacterial protein for light and heavy chain variable regions respectively. Expression of the heavy chain variable region gene was increased by including a longer Shine-Dalgarno sequence. Similar constructions in the light chain vector had no effect on expression levels. The insoluble variable region polypeptides were reconstituted into a heterodimer possessing the full antigen binding characteristics of both the parent monoclonal antibody and its Fab fragment.

Animals↗

Leaf Rust in Rye: From Pathogen Biology to Host Defense and Resistance Breeding.

Leaf rust (LR), caused by Puccinia recondita f. sp. secalis (Prs), is considered one of the most dangerous rye (Secale cereale L.) diseases, causing yield losses exceeding 35%. This review summarizes all currently available data about this disease: pathogen characteristics (including its life cycle, natural variation, and disease symptoms), resistance resources, and the background of the plant immune response at the genome, transcriptome, and metabolome levels. The research conducted so far has allowed for the identification of dozens of genes that play a significant role in the rye immune response to Prs infection. Among them, genes encoding NBS-LRR proteins (including SECCE1Rv1G0014220, the most likely Pr3 candidate), glycosyltransferase, β-1,3-glucanase, 1-deoxy-D-xylulose 5-phosphate synthase, β-1,3-glucanase, UDP-glycosyltransferase, pathogenesis-related protein 1, ammonium transporter, and cytochrome P450 enzymes are candidates for seedling and all-stage resistance, whereas ScLr_ABC25 currently represents the most promising candidate associated with adult-plant resistance. Among the metabolites differentially accumulated in response to Prs, those related to phenylpropanoids, diterpenoids, and thiamine branches seem to play the most important role in the immune response. Finally, we suggest how the knowledge acquired so far about the rye-Prs interaction can be used in modern breeding programs aimed at obtaining cultivars with enhanced resistance to LR, such as through the use of functional gene markers and/or metabolic biomarker-assisted selection and, in the more distant future, by developing and applying new genomic techniques for precise editing of resistance and susceptibility genes, engineering synthetic immune receptors and decoys, and pan-genomic exploration for identification of rare or lineage-specific resistance alleles. [Formula: see text] Copyright © 2026 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Plant Diseases↗

The evolution of medical technology: lessons from the Burgess Shale.

Many forthcoming medical advances-growth factors, tissue engineering, gene therapy, attachable prosthetic limbs, and implantable computers--are so new that as yet there is no clinical experience with them. Each therapeutic technique will evolve in an environment containing few guideposts to help judge its efficacy and safety. Recent developments in evolution theory (based on an analysis of Cambrian fossils in Canada's Burgess Shale quarry) suggest that evolution passes, at times, through innovative cycles of progress--when diversification of design leads to perfection of form--with the concomitant production of many unsuccessful models. The evolution of the total knee replacement is a perfect example of the process, because many of the early devices have proven to be dismal failures. However, modern knee replacements would not have been developed without them. Because the risk of unforeseen complications associated with new medical products cannot be discerned in advance, each patient-consumer should have the opportunity to intelligently weigh an innovative product's risk potential against its possible benefit. The proposal made here, for a temporary New Product status for new drugs and devices after a product is cleared by the Food and Drug Administration for general marketing, provides a mechanism for making such decisions.

Humans↗

Generation of cohesive ends on PCR products by UDG-mediated excision of dU, and application for cloning into restriction digest-linearized vectors.

We have investigated the use of dU excision by uracil N-glycosylase (UDG) to create cohesive ends on PCR fragments "mimicking" those generated by restriction enzymes. The feasibility of this approach for directional and nondirectional cloning using cohesive ends mimicking SacI or PstI ends is demonstrated by the subcloning of a 383 to 388-bp fragment of bovine basic fibroblast growth factor into restriction enzyme-linearized pT7T318U. UDG-mediated cohesive ends imperfectly matched to PstI-generated vector ends gave reasonable cloning efficiency and accuracy, suggesting that the approach may be extended to mimicry of other restriction enzymes producing 3' overhangs. The rapid and specific excision of dU by UDG (within 30 min at 37 degrees C) has several potential advantages over the use of restriction site-modified primers, including the avoidance of restriction cleavage at internal sites within the PCR product. Also, following ligation, the approach described may be used to prevent subsequent cleavage of the joined DNA segments by the restriction enzyme, that is, by not recreating the restriction enzyme recognition sequence at the junction, which may find application in gene engineering. By adapting the approach to use dU-containing linkers or "vectorettes," the approach may be used for cloning unknown sequences (e.g., by cDNA or genomic library construction) or for mimicking 5' overhang cohesive ends on PCR fragments.

Animals↗

Insulin and insulin-like growth factor 1 stimulate proliferation of metastatic variants of colon carcinoma 26.

The proliferation rate of malignant cells in vivo is one of the important factors which affect the formation of tumor metastasis. A highly metastatic variant of mouse colon adenocarcinoma 26 (NL-17) grew more rapidly than a low-metastatic variant (NL-44) both in vitro and in vivo. The effect of growth factors on the proliferation of NL-17 and NL-44 cells was examined in serum-free medium. Among growth factors examined, human insulin and insulin-like growth factor 1 (IGF-1), which were produced by gene engineering techniques, stimulated the growth of metastatic NL-17 and NL-44 cells as determined by thymidine incorporation and cell counts. DNA synthesis and cell proliferation of the high-metastatic NL-17 was stimulated to a greater extent by insulin and IGF-1 than those of the low-metastatic NL-44. These findings suggest that circulating growth factors could enhance the formation of tumor metastasis. Scatchard analysis of [125I]IGF-1 binding to NL-17 and NL-44 showed that each cell line had an almost equal number of IGF-1 receptors (1.37 x 10(5)/cell and 1.26 x 10(5)/cell, respectively), which had similar dissociation constants (8.94 x 10(-10) M and 9.54 x 10(-10) M, respectively). Since the number and affinity of IGF-1 receptors are equivalent between low- and high-metastatic cells, the intracellular events which result in the cell growth after binding of IGF-1 may differ between NL-17 and NL-44 cells.

Adenocarcinoma↗

Perspectives on cancer immuno-epidemiology.

Estimating human cancer risk based on host-environment interaction is one task of epidemiology, and it has provided indispensable knowledge for prevention of cancer. The recent develop-ment of gene-engineered mice has also provided solid evidence about the relationship between cancer development and immunity. The aim of this review is to discuss the possible contribution of epidemiology to understanding the role of immunity in host defense against cancer, and also to assess the involvement of inflammation in the occurrence of selected cancers. Here we look at the concepts of cancer immunosurveillance and infection-inflammation-cancer, and include a brief introduction to recent studies in humans and experimental animal models. It has been postulated for many years that the immune system has the ability to recognize and eliminate nascent transformed cells in the body (so-called cancer immunosurveillance hypothesis), and this idea has recently obtained strong support from animal experiments. In humans, follow-up studies among immunosuppressed transplant recipients revealed a remarkably increased risk of not only selected malignancies, but also cancers with no known viral etiology. On the other hand, a prospective cohort study among the general population revealed that individuals with low natural cytotoxic activity of peripheral blood lymphocytes had an increased risk of cancer development. More studies are warranted to allow the construction of a model for the interaction between host immunity, aging, and the environment. The host immune system is also involved in inflammatory responses to pathogen infection: insufficient immune function of the host, or repeated infection, may result in persistent inflammation, where growth/survival factors continuously act on initiated cells. The combined use of biomarkers will be necessary to define low-grade persistent inflammation in future cohort studies; and, in addition to these phenotype marker-based cohort studies, one plausible future direction will be a genomic approach that can be undertaken within cohort studies, looking at the genetic background underlying individual variations in phenotype markers.

Animals↗

The critical role of type-1 innate and acquired immunity in tumor immunotherapy.

The discovery of a large array of tumor antigens has demonstrated that host lymphocytes can indeed recognize and destroy tumor cells as originally proposed in the cancer immunosurveillance hypothesis. Recent reports that led to the cancer immunoediting concept also strongly support the immunosurveillance hypothesis, and they further indicate that the host immune system plays a critical role not only in promoting host protection against cancer but also in selecting tumors that can better escape from immune attack. Thus, it is now clear that T cells have the ability to recognize and destroy spontaneously arising tumors. However, the generation of antitumor immunity is often difficult in the tumor-bearing host because of various negative regulatory mechanisms. Here, we review our recent work on tumor immunotherapy, which utilizes the activation of type-1 innate and/or acquired immunity as a potent strategy to overcome immunosup-pression in the tumor-bearing host. We have established a variety of tumor therapeutic protocols that aim to activate type-1 immunity, such as tumor-vaccine therapy with CpG encapsulat-ed in liposomes, cell therapy using tumor-specific Th1 cells, and gene therapy using gene-engineered Th1 cells. We found that CpG encapsulated in liposomes stimulated IL-12-producing DC and induced IFN-gamma-producing NK cells, NKT cells, and tumor-specific CTL. Th1 cell therapy was also shown to be beneficial for acceleration of APC/Th1 cell-cell interaction in the DLN, which was critical for inducing tumor-specific CTL at the tumor site. Therefore, we conclude that the activation of type-1 innate and acquired immunity is crucial for tumor immunotherapy in order to overcome strong immunosuppression in the tumor-bearing host.

Animals↗

Properties of truncated forms of the elongation factor 1alpha from the archaeon Sulfolobus solfataricus.

Two truncated forms of the Sulfolobus solfataricus elongation factor 1alpha (SsEF-1alpha), corresponding to the putative domains G+M, Ss(GM)EF-1alpha, and G, Ss(G)EF-1alpha, have been constructed by gene engineering, produced in Escherichia coli and purified. Neither truncated form was able to sustain poly(Phe) synthesis but they were able to bind guanine nucleotides with an affinity much higher with respect to that of the intact factor. However, the difference in the affinity for GDP and GTP became progressively reduced with the extent of the truncation. The values of kcat and Km for GTP of the intrinsic GTPase of SsEF-1alpha triggered by 3.6 M NaCl were not affected by the deletions. In contrast, both Ss(GM)EF-1alpha and Ss(G)EF-1alpha were less thermostable than the intact factor; the region of the factor most responsible for the loss of resistance against heat inactivation was the C-terminal domain. On the other hand the domain M was the regulator of the thermophilicity of SsEF-1alpha since only Ss(G)EF-1alpha showed a reduced thermophilicity. Remarkably, both Ss(GM)EF-1alpha and Ss(G)EF-1alpha were able to exchange [3H]GDP for GTP at a very high rate so that they were no more sensitive to the stimulatory effect of SsEF-1beta, which is the nucleotide exchange factor of SsEF-1alpha.

Bacterial Proteins↗

Vertebrectomy, bone allograft fusion, and antitumor vaccination for the treatment of vertebral fibrosarcoma in a dog.

OBJECTIVE: To describe the surgical technique of vertebrectomy with bone allograft fusion and the use of antitumor vaccine for the treatment of a primary vertebral neoplasm in a dog. STUDY DESIGN: Case Report. ANIMALS OR SAMPLE POPULATION: A 3 year old 32 kg female spayed mixed breed dog with progressive paraplegia. METHODS: Myelography was performed to identify an L5 lytic lesion with spinal cord compression. A dorsal laminectomy was performed to decompress the spinal cord and obtain biopsies. Pathologic fracture of the vertebral body two days later was treated with L5 vertebrectomy, cortical allograft implantation, and bilateral plating from L4 to L6. Tumor samples were used to create an autologous cytokine-gene-engineered tumor cell vaccine. Recheck radiographs and neurologic examinations were obtained 1, 2, 7, and 13 months after surgery. RESULTS: The histopathologic diagnosis was fibrosarcoma. Although slight osteopenia of the allograft was noted thirteen months after surgery, the allograft and plate fixation remained stable. The patient tolerated the antitumor vaccination protocol well. Two years after the procedures the dog was able to ambulate normally but remained urinary and fecal incontinent. CONCLUSIONS AND CLINICAL RELEVANCE: Vertebrectomy and cortical allograft implantation with plating permitted this patient to return to a functional lifestyle with its owners.

Animals↗

Genomic medicine: exploring the basis of a new approach to endocrine hypertension.

Recent improvements in defining the molecular basis of disease have encouraged scientists worldwide to develop new therapeutic strategies based on engineered genes and cells. Genomic medicine has the potential to revolutionize diagnosis and therapy of a variety of human diseases, including endocrine disorders. Hypertension is the presenting feature of some of these disorders, such as congenital adrenal diseases, and adrenal and pituitary tumors. Preclinical data indicate that gene transfer to both the adrenal gland and the pituitary is not only feasible but also quite efficient. Research in this field is only in its infancy, but with the ever-increasing advances in DNA technologies, genomic therapies for endocrine hypertension may become available within the next few decades.

Endocrine Glands↗

Infectious disease issues in xenotransplantation.

Xenotransplantation, the transplantation of living organs, tissues, or cells from one species to another, is viewed as a potential solution to the existing shortage of human organs for transplantation. While whole-organ xenotransplantation is still in the preclinical stage, cellular xenotransplantation and extracorporeal perfusion applications are showing promise in early clinical trials. Advances in immunosuppressive therapy, gene engineering, and cloning of animals bring a broader array of xenotransplantation protocols closer to clinical trials. Despite several potential advantages over allotransplantation, xenotransplantation encompasses a number of problems. Immunologic rejection remains the primary hindrance. The potential to introduce infections across species barriers, another major concern, is the main focus of this review. Nonhuman primates are unlikely to be a main source for xenotransplantation products despite their phylogenetic proximity to humans. Genetically engineered pigs, bred under special conditions, are currently envisaged as the major source. Thus far, there has been no evidence for human infections caused by pig xenotransplantation products. However, the existence of xenotropic endogenous retroviruses and the clinical evidence of long-lasting porcine cell microchimerism indicate the potential for xenogeneic infections. Thus, further trials should continue under regulatory oversight, with close clinical and laboratory monitoring for potential xenogeneic infections.

Animals↗

Three immunoproteasome-associated subunits cooperatively generate a cytotoxic T-lymphocyte epitope of Epstein-Barr virus LMP2A by overcoming specific structures resistant to epitope liberation.

The precise roles of gamma interferon-inducible immunoproteasome-associated molecules in generation of cytotoxic T-lymphocyte (CTL) epitopes have yet to be fully elucidated. We describe here a unique epitope derived from the Epstein-Barr virus (EBV) latent membrane protein 2A (LMP2A) presented by HLA-A*2402 molecules. Generation of the epitope, designated LMP2A(222-230), from the full-length protein requires the immunoproteasome subunit low-molecular-weight protein 7 (ip-LMP7) and the proteasome activator 28-alpha subunit and is accelerated by ip-LMP2, as revealed by gene expression experiments using an LMP2A(222-230)-specific CTL clone as a responder in enzyme-linked immunospot assays. The unequivocal involvement of all three components was confirmed by RNA interference gene silencing. Interestingly, the LMP2A(222-230) epitope could be efficiently generated from incomplete EBV-LMP2A fragments that were produced by puromycin treatment or gene-engineered shortened EBV-LMP2A lacking some of its hydrophobic domains. In addition, epitope generation was increased by a single amino acid substitution from leucine to alanine immediately flanking the C terminus, this being predicted by a web-accessible program to increase the cleavage strength. Taken together, the data indicate that the generation of LMP2A(222-230) is influenced not only by extrinsic factors such as immunoproteasomes but also by intrinsic factors such as the length of the EBV-LMP2A protein and proteasomal cleavage strength at specific positions in the source antigen.

Alanine↗