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The Journal of Clinical Investigation Oct 2020Transcription infidelity (TI) is a mechanism that increases RNA and protein diversity. We found that single-base omissions (i.e., gaps) occurred at significantly higher...
Transcription infidelity (TI) is a mechanism that increases RNA and protein diversity. We found that single-base omissions (i.e., gaps) occurred at significantly higher rates in the RNA of highly allergenic legumes. Transcripts from peanut, soybean, sesame, and mite allergens contained a higher density of gaps than those of nonallergens. Allergen transcripts translate into proteins with a cationic carboxy terminus depleted in hydrophobic residues. In mice, recombinant TI variants of the peanut allergen Ara h 2, but not the canonical allergen itself, induced, without adjuvant, the production of anaphylactogenic specific IgE (sIgE), binding to linear epitopes on both canonical and TI segments of the TI variants. The removal of cationic proteins from bovine lactoserum markedly reduced its capacity to induce sIgE. In peanut-allergic children, the sIgE reactivity was directed toward both canonical and TI segments of Ara h 2 variants. We discovered 2 peanut allergens, which we believe to be previously unreported, because of their RNA-DNA divergence gap patterns and TI peptide amino acid composition. Finally, we showed that the sIgE of children with IgE-negative milk allergy targeted cationic proteins in lactoserum. We propose that it is not the canonical allergens, but their TI variants, that initiate sIgE isotype switching, while both canonical and TI variants elicit clinical allergic reactions.
Topics: 2S Albumins, Plant; Adolescent; Allergens; Anaphylaxis; Animals; Antigens, Plant; Arachis; Cattle; Child; Child, Preschool; Fabaceae; Female; Frameshifting, Ribosomal; Genetic Variation; Humans; Immune Sera; Immunoglobulin E; Male; Mice; Mice, Inbred BALB C; Milk Hypersensitivity; Peanut Hypersensitivity; Phaseolus; Plant Proteins; Recombinant Proteins; Glycine max; Transcription, Genetic
PubMed: 32634131
DOI: 10.1172/JCI126275 -
Journal of Experimental & Clinical... Apr 2023Colorectal cancer (CRC) is the third most lethal cancer in the world, and its incidence is steadily rising. In this study, we investigated the induction of humoral...
BACKGROUND
Colorectal cancer (CRC) is the third most lethal cancer in the world, and its incidence is steadily rising. In this study, we investigated the induction of humoral immunity by a phytogalactolipid enriched fraction (CRA) derived from the medicinal plant Crassocephalum rabens (Benth.) S. Moore to combat CRC.
METHODS
Immunocompetent BALB/c mice were used to evaluate CRA's therapeutic effects in CRC. The phenotypes of B cell subsets in splenocytes and tumors from the CRA-treated mice were isolated and analyzed by flow cytometry. The titers, isotypes, specificity, antigen recognition, and cytotoxic activity of CRA-induced anti-tumor antibodies were determined. The mechanisms of CRA on B cell differentiation were determined by cell-based analyses, including co-cultural with T cells, cytokine analysis, gene expression by qPCR, and protein expression by western blotting.
RESULTS
CRA efficiently inhibited tumor growth in colorectal tumor-bearing allograft mice. CRA treatment attracted an abundance of B cells into the tumor consequently enhancing the anti-tumor antibodies in sera and inducing a class-switch. CRA-induced antisera (designated CRA antisera) specifically recognized surface antigens on the plasma membrane of cancer cells. CRA antisera induced cytotoxicity including antibody-dependent cell cytotoxicity, phagocytosis, and complement-dependent cytotoxicity. CRA interacted with IL-6 receptor to activate STAT3 and cMaf, resulting in T cell secretion of IL-21, which, in turn induced B cell differentiation through the IL-21R/STAT3/Blimp-1 pathway.
CONCLUSIONS
CRA regulated T cell activity resulting in B cell activation and triggering of anti-tumor antibodies to impede CRC progression.
Topics: Mice; Animals; Immunity, Humoral; Colorectal Neoplasms; Antineoplastic Agents; Cytokines; Immune Sera
PubMed: 37081540
DOI: 10.1186/s13046-023-02660-x -
Current Pharmaceutical Design 2022Snakebites have been declared a neglected health problem that is considered a national disease by the WHO (world health organisation). Asian countries like India have...
Snakebites have been declared a neglected health problem that is considered a national disease by the WHO (world health organisation). Asian countries like India have high snakebite death rates due to short antidotes and poorly equipped doctors. In today's scenario, local resources like herbs need to be used to prepare cheap antidotes and are often available to victims. Snake bites should be viewed as an emergency problem and require additional national guidelines, doctor training, expertise, and human concentration for effective and timely treatment-measures to be taken to ensure the availability and mass production of antidotes. Currently available, antidotes have problems with storage, manufacture, and aspects of the results. Attention should be paid to the natural compound Gedunin with antitoxic effects. To determine Gedunin's therapeutic efficacy, well-designed clinical research is required. This article emphasizes and proves the therapeutic effectiveness of the herbal plant active ingredient Gedunin against snakebites.
Topics: Antidotes; Antivenins; Asia; Humans; Snake Bites
PubMed: 35440297
DOI: 10.2174/1381612828666220417134118 -
BMC Emergency Medicine Jan 2022Green pit vipers (GPVs), namely Trimeresurus albolabris and Trimeresurus stejnegeri accounts for most snakebites in Southern China. Green pit viper venom contains... (Observational Study)
Observational Study
Effectiveness of clotting factor replacement therapy after antivenom treatment on coagulopathic envenomation following green pit viper bites: a retrospective observational study.
BACKGROUND
Green pit vipers (GPVs), namely Trimeresurus albolabris and Trimeresurus stejnegeri accounts for most snakebites in Southern China. Green pit viper venom contains thrombin-like enzymes, resulting in defibrination syndrome. Using of clotting factor replacement after antivenom administration is controversial. The objective of this study was to investigate the effects of clotting factor replacement in coagulopathic patients with T. albolabris and T. stejnegeri bites after antivenom administration.
METHODS
We retrospectively reviewed 123 patients who were bitten by T. albolabris and T. stejnegeri and were admitted to the Emergency Department of a hospital in Guangzhou, Southern China, from 2013 to 2019. Recovery of prothrombin time (PT) and fibrinogen level were compared among (1) fresh-frozen plasma (FFP) group; (2) cryoprecipitate (cryo) group; (3) FFP and cryo group; and (4) control group after antivenom administration.
RESULTS
The incidence of coagulopathy was 31%. Persistent and late coagulopathy were the most common patterns among four groups. The median reduction in PT was 20.1 ± 31.2 s for FFP and cryo group. The median increase in fibrinogen level was very small: 0.05 ± 0.20 g/L for FFP group, 0.09 ± 0.37 g/L for cryo group and 0.07 ± 0.31 g/L for FFP and cryo group, respectively. The percentage of unimproved PT was markedly higher in the FFP and cryo group than the control group (P = 0.01 by log-rank test, P = 0.02 by Gehan-Breslow-Wilcoxon test). The percentage of unimproved fibrinogen level tended to be worse in the FFP and cryo group than the control group, but the different was marginal (P = 0.05 by Gehan-Breslow-Wilcoxon test, P = 0.07 by log-rank test). A total of 7.8% (7/90) of the patients in the clotting factor replacement groups developed anaphylaxis and heart failure.
CONCLUSION
There is no improvement in coagulopathy profile in patients with T. albolabris and T. stejnegeri bites who received clotting factor replacement after antivenom administration. But the results from GPVs may not be generalized to other species of venomous snakes.
Topics: Animals; Antivenins; Blood Coagulation Factors; Fibrinogen; Humans; Retrospective Studies; Snake Bites; Trimeresurus
PubMed: 35045831
DOI: 10.1186/s12873-022-00569-w -
Indian Journal of Pediatrics Aug 2023
Topics: Humans; Animals; Antivenins; Bites and Stings; Lizards
PubMed: 37256448
DOI: 10.1007/s12098-023-04673-y -
Archives of Toxicology Jan 2023Snake venoms are heterogeneous mixtures of proteins and peptides used for prey subjugation. With modern proteomics there has been a rapid expansion in our knowledge of... (Review)
Review
Snake venoms are heterogeneous mixtures of proteins and peptides used for prey subjugation. With modern proteomics there has been a rapid expansion in our knowledge of snake venom composition, resulting in the venom proteomes of 30% of vipers and 17% of elapids being characterised. From the reasonably complete proteomic coverage of front-fanged snake venom composition (179 species-68 species of elapids and 111 species of vipers), the venoms of vipers and elapids contained 42 different protein families, although 18 were only reported in < 5% of snake species. Based on the mean abundance and occurrence of the 42 protein families, they can be classified into 4 dominant, 6 secondary, 14 minor, and 18 rare protein families. The dominant, secondary and minor categories account for 96% on average of a snake's venom composition. The four dominant protein families are: phospholipase A (PLA), snake venom metalloprotease (SVMP), three-finger toxins (3FTx), and snake venom serine protease (SVSP). The six secondary protein families are: L-amino acid oxidase (LAAO), cysteine-rich secretory protein (CRiSP), C-type lectins (CTL), disintegrins (DIS), kunitz peptides (KUN), and natriuretic peptides (NP). Venom variation occurs at all taxonomic levels, including within populations. The reasons for venom variation are complex, as variation is not always associated with geographical variation in diet. The four dominant protein families appear to be the most important toxin families in human envenomation, being responsible for coagulopathy, neurotoxicity, myotoxicity and cytotoxicity. Proteomic techniques can be used to investigate the toxicological profile of a snake venom and hence identify key protein families for antivenom immunorecognition.
Topics: Humans; Proteomics; Snake Venoms; Antivenins; Toxins, Biological; Proteome; Peptides
PubMed: 36437303
DOI: 10.1007/s00204-022-03420-0 -
Frontiers in Immunology 2023Syphilis, a sexually transmitted infection caused by the spirochete (), is resurging globally. 's repertoire of outer membrane proteins (OMPs) includes BamA (β-barrel...
INTRODUCTION
Syphilis, a sexually transmitted infection caused by the spirochete (), is resurging globally. 's repertoire of outer membrane proteins (OMPs) includes BamA (β-barrel assembly machinery subunit A/TP0326), a bipartite protein consisting of a 16-stranded β-barrel with nine extracellular loops (ECLs) and five periplasmic POTRA (polypeptide transport-associated) domains. BamA ECL4 antisera promotes internalization of by rabbit peritoneal macrophages.
METHODS
Three overlapping BamA ECL4 peptides and a two-stage, phage display strategy, termed "Epivolve" (for epitope evolution) were employed to generate single-chain variable fragments (scFvs). Additionally, antisera generated by immunizing mice and rabbits with BamA ECL4 displayed by a thioredoxin scaffold (Trx). MAbs and antisera reactivities were evaluated by immunoblotting and ELISA. A comparison of murine and rabbit opsonophagocytosis assays was conducted to evaluate the functional ability of the Abs (, opsonization) and validate the mouse assay. Sera from -infected mice (MSS) and rabbits (IRS) were evaluated for ECL4-specific Abs using Trx and overlapping ECL4 peptides in immunoblotting and ELISA assays.
RESULTS
Each of the five mAbs demonstrated reactivity by immunoblotting and ELISA to nanogram amounts of Trx. One mAb, containing a unique amino acid sequence in both the light and heavy chains, showed activity in the murine opsonophagocytosis assay. Mice and rabbits hyperimmunized with Trx produced opsonic antisera that strongly recognized the ECL presented in a heterologous scaffold and overlapping ECL4 peptides, including S2. In contrast, Abs generated during infection of mice and rabbits poorly recognized the peptides, indicating that S2 contains a subdominant epitope.
DISCUSSION
Epivolve produced mAbs target subdominant opsonic epitopes in BamA ECL4, a top syphilis vaccine candidate. The murine opsonophagocytosis assay can serve as an alternative model to investigate the opsonic potential of vaccinogens. Detailed characterization of BamA ECL4-specific Abs provided a means to dissect Ab responses elicited by infection.
Topics: Mice; Animals; Rabbits; Treponema pallidum; Antibodies, Monoclonal; Syphilis; Immune Sera; Bacteriophages; Epitopes
PubMed: 37675118
DOI: 10.3389/fimmu.2023.1222267 -
Frontiers in Cellular and Infection... 2020Persistence has evolved as a potent survival strategy to overcome adverse environmental conditions. This capability is common to almost all bacteria, including all human... (Review)
Review
Persistence has evolved as a potent survival strategy to overcome adverse environmental conditions. This capability is common to almost all bacteria, including all human bacterial pathogens and likely connected to chronic infections caused by some of these pathogens. Although the majority of a bacterial cell population will be killed by the particular stressors, like antibiotics, oxygen and nitrogen radicals, nutrient starvation and others, a varying subpopulation (termed persisters) will withstand the stress situation and will be able to revive once the stress is removed. Several factors and pathways have been identified in the past that apparently favor the formation of persistence, such as various toxin/antitoxin modules or stringent response together with the alarmone (p)ppGpp. However, persistence can occur stochastically in few cells even of stress-free bacterial populations. Growth of these cells could then be induced by the stress conditions. In this review, we focus on the persister formation of human intracellular bacterial pathogens, some of which belong to the most successful persister producers but lack some or even all of the assumed persistence-triggering factors and pathways. We propose a mechanism for the persister formation of these bacterial pathogens which is based on their specific intracellular bipartite metabolism. We postulate that this mode of metabolism ultimately leads, under certain starvation conditions, to the stalling of DNA replication initiation which may be causative for the persister state.
Topics: Anti-Bacterial Agents; Antitoxins; Bacteria; Escherichia coli; Humans
PubMed: 33520740
DOI: 10.3389/fcimb.2020.615450 -
Nature Feb 2022The Omicron (B.1.1.529) variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was initially identified in November 2021 in South Africa and Botswana,...
The Omicron (B.1.1.529) variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was initially identified in November 2021 in South Africa and Botswana, as well as in a sample from a traveller from South Africa in Hong Kong. Since then, Omicron has been detected globally. This variant appears to be at least as infectious as Delta (B.1.617.2), has already caused superspreader events, and has outcompeted Delta within weeks in several countries and metropolitan areas. Omicron hosts an unprecedented number of mutations in its spike gene and early reports have provided evidence for extensive immune escape and reduced vaccine effectiveness. Here we investigated the virus-neutralizing and spike protein-binding activity of sera from convalescent, double mRNA-vaccinated, mRNA-boosted, convalescent double-vaccinated and convalescent boosted individuals against wild-type, Beta (B.1.351) and Omicron SARS-CoV-2 isolates and spike proteins. Neutralizing activity of sera from convalescent and double-vaccinated participants was undetectable or very low against Omicron compared with the wild-type virus, whereas neutralizing activity of sera from individuals who had been exposed to spike three or four times through infection and vaccination was maintained, although at significantly reduced levels. Binding to the receptor-binding and N-terminal domains of the Omicron spike protein was reduced compared with binding to the wild type in convalescent unvaccinated individuals, but was mostly retained in vaccinated individuals.
Topics: 2019-nCoV Vaccine mRNA-1273; Adult; Antibodies, Monoclonal; Antibodies, Neutralizing; Antibodies, Viral; BNT162 Vaccine; COVID-19; COVID-19 Vaccines; Convalescence; Female; Humans; Immune Evasion; Immune Sera; Immunization, Secondary; Models, Molecular; Neutralization Tests; SARS-CoV-2; Spike Glycoprotein, Coronavirus
PubMed: 35016197
DOI: 10.1038/s41586-022-04399-5 -
Haematologica Oct 2019
Topics: Anemia, Aplastic; Antilymphocyte Serum; Child; Humans; Immunosuppression Therapy; United States
PubMed: 31575670
DOI: 10.3324/haematol.2019.225870