Recent studies have highlighted the promise of targeting tumor neoantigens to generate potent antitumor immune responses and provide strong motivation for improving our understanding of antigen-T-cell receptor (TCR) interactions. Advances in single-cell sequencing technologies have opened the door for detailed investigation of the TCR repertoire, providing paired information from TCRα and TCRβ, which together determine specificity. However, a need remains for efficient methods to assess the specificity of discovered TCRs. We developed a streamlined approach for matching TCR sequences with cognate antigen through on-demand cloning and expression of TCRs and screening against candidate antigens. Here, we first demonstrate the system's capacity to identify viral-antigen-specific TCRs and compare the functional avidity of TCRs specific for a given antigen target. We then apply this system to identify neoantigen-specific TCR sequences from patients with melanoma treated with personalized neoantigen vaccines and characterize functional avidity of neoantigen-specific TCRs. Furthermore, we use a neoantigen-prediction pipeline to show that an insertion-deletion mutation in a putative chronic lymphocytic leukemia (CLL) driver gives rise to an immunogenic neoantigen mut- and use this approach to identify the mut--specific TCR sequence. This approach provides a means to identify and express TCRs, and then rapidly assess antigen specificity and functional avidity of a reconstructed TCR, which can be applied for monitoring antigen-specific T-cell responses, and potentially for guiding the design of effective T-cell-based immunotherapies.
Treatment with epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs), such as gefitinib and erlotinib, has achieved high clinical response rates in patients with non–small cell lung cancers (NSCLCs). However, over time, most tumors develop acquired resistance to EGFR-TKIs, which is associated with the secondary EGFR T790M resistance mutation in about half the cases. Currently there are no effective treatment options for patients with this resistance mutation. Here we identified two novel HLA-A*0201 (A2)-restricted T cell epitopes containing the mutated methionine residue of the EGFR T790M mutation, T790M-5 (MQLMPFGCLL) and T790M-7 (LIMQLMPFGCL), as potential targets for EGFR-TKI-resistant patients. When peripheral blood cells were repeatedly stimulated in vitro with these two peptides and assessed by antigen-specific IFN-γ secretion, T cell lines responsive to T790M-5 and T790M-7 were established in 5 of 6 (83%) and 3 of 6 (50%) healthy donors, respectively. Additionally, the T790M-5- and T790M-7-specific T cell lines displayed an MHC class I-restricted reactivity against NSCLC cell lines expressing both HLA-A2 and the T790M mutation. Interestingly, the NSCLC patients with antigen-specific T cell responses to these epitopes showed a significantly less frequency of EGFR-T790M mutation than those without them [1 of 7 (14%) vs 9 of 15 (60%); chi-squared test, p = 0.0449], indicating the negative correlation between the immune responses to the EGFR-T790M-derived epitopes and the presence of EGFR-T790M mutation in NSCLC patients. This finding could possibly be explained by the hypothesis that immune responses to the mutated neo-antigens derived from T790M might prevent the emergence of tumor cell variants with the T790M resistance mutation in NSCLC patients during EGFR-TKI treatment. Together, our results suggest that the identified T cell epitopes might provide a novel immunotherapeutic approach for prevention and/or treatment of EGFR-TKI resistance with the secondary EGFR T790M resistance mutation in NSCLC patients.
An ascorbate analog labeled with iodine-131, 6-deoxy-6-[131 I]iodo-L-ascorbic acid was prepared for evaluation as an in vivo tracer of L-ascorbic acid. The no-carrier-added radiosynthesis was conducted by nucleophilic bromine-iodine exchange between the brominated precursor and sodium [131 I]iodide in 2-pentanone at 130-1401C. HPLC purification using a reversephase column gave 6-deoxy-6-[ 131 I]iodo-L-ascorbic acid in radiochemical yield of 36-60% with high radiochemical purity and satisfactory-specific radioactivity in a total preparation time of 90 min. Biodistribution studies in fibrosarcoma-bearing mice showed a high uptake in the adrenal glands, accompanied by low activity of tumor accumulation, accumulation properties similar to previous results obtained with 14 C-labeled ascorbic acid and 6-deoxy-6-[ 18 F]fluoro-L-ascorbic acid, in spite of high level of deiodination.
Over the past few decades, a number of radiopharmaceuticals for noninvasive imaging of the adrenal glands by the nuclear imaging technique have been evolved, designed by targeting specific metabolic or synthetic processes within the gland.1,2) Among the current developments and the expansion of new molecular imaging modalities and specific probes, adrenal scintigraphy using more specific radiotracers to obtain functional information for tissue characterization is still challenging. 3,4)The adrenal gland is among the organs with the highest concentration of L-ascorbic acid (AsA) in the body and is particularly sensitive to deficiencies of AsA.5) It is well known that AsA is an important cofactor required both in catecholamine biosynthesis and in adrenal steroidogenesis, and that it functions as a water-soluble antioxidant in the adrenal gland. [5][6][7][8][9] The cellular uptake of AsA and its distribution in cells are important factors that determine its inherent activity. Studies of tissue distribution of radioactivity in animals after injection of 14 C-labeled AsA ( 14 C-AsA) were reported in the 1960s, showing a remarkable uptake of radioactivity in the adrenal glands, pituitary glands and parotid glands.10-12) Diagnostic application of AsA as a radiotracer for imaging the adrenals, however, remains to be limited by relatively high accumulations of 14 C-AsA in the liver and kidneys. 13)Recent biochemical studies have demonstrated that AsA is taken up into cells by the sodium-dependent vitamin C transporter (SVCT-1 and -2), whereas oxidized vitamin C (dehydroascorbic acid) is transported via glucose transporters. [14][15][16][17][18][19] SVCT-1 is expressed in epithelial organs such as the liver and kidneys, whereas SVCT-2 is found in the adrenal glands and lungs. [14][15][16][17][18][19] In particular, SVCT-2 is primarily responsible for the uptake of AsA from blood circulation into the adrenal cells. [14][15][16][17][18][19] The adrenals have been shown to have the largest falls in the AsA levels in mice with a deficiency of 20) and the influence of the depletion of tissue AsA on tissue catecholamines was found to be most prominent in the adrenals. 21,22) In addition, it has recently been shown that overexpression of adrenal SVCT-2 mRNA in diabetic mice resulted in increased uptake of AsA. 23) Thus, it is most likely that the AsA transport mechanism plays an important role in the pathologic processes of the adrenals. 24) We became interested in the possibility that appropriate structural AsA analogs with specific transport characteristics, if possessing favorable in vivo distribution properties, might be used as tracer agents for the visualization of biochemical events associated with the action of AsA in the adrenal glands. Several AsA analogs labeled with 18 F, 131 I, 125 I, or 99m Tc were prepared and their potential imaging characteristics were evaluated in animals. [25][26][27][28][29][30][31] 6-Deoxy-6-iodo-L-ascorbic acid (6-IAsA) has been shown to be an effective inhibitor of AsA transport, with tran...
If fire breaks out on an airplane, a large amount of fire extinguishing agents should be discharged within a very short time. For effective fire extinguishing, increased discharge velocity of the fire extinguishing agents is required. This can be achieved by using a large-sized vessel in which the fire extinguishing agents are highly pressurized by noncombustible gases. It is important to understand the flow characteristics of a fire extinguishing system for optimal system design. This study reports a numerical analysis of the flow characteristics of an airplane fire extinguishing system using halon-1301 as a fire extinguishing agent. The unsteady flow model was simulated with the general-purpose software package "FLUENT", to study the flow characteristics of the fire extinguishing agents in the system. The effects of the rupture surface area and tube diameter on the flow characteristics were investigated for optimal system design. From the analysis results, it was clarified that the characteristics of the halon discharge from the end of tube are very sensitive to the rupture surface area and significantly affected by the tube diameter.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.