Epsilon antitoxin

About: Epsilon antitoxin is a research topic. Over the lifetime, 24 publications have been published within this topic receiving 424 citations. The topic is also known as: Epsilon_antitox & IPR015090.

The ClpXP Protease Is Responsible for the Degradation of the Epsilon Antidote to the Zeta Toxin of the Streptococcal pSM19035 Plasmid

Abstract: Most bacterial genomes contain different types of toxin-antitoxin (TA) systems. The ω-ϵ-ζ proteinaceous type II TA cassette from the streptococcal pSM19035 plasmid is a member of the ϵ/ζ family, which is commonly found in multiresistance plasmids and chromosomes of various human pathogens. Regulation of type II TA systems relies on the proteolysis of antitoxin proteins. Under normal conditions, the Epsilon antidote neutralizes the Zeta toxin through the formation of a tight complex. In this study, we show, using both in vivo and in vitro analyses, that the ClpXP protease is responsible for Epsilon antitoxin degradation. Using in vivo studies, we examined the stability of the plasmids with active or inactive ω-ϵ-ζ TA cassettes in B. subtilis mutants that were defective for different proteases. Using in vitro assays, the degradation of purified His6-Epsilon by the His6-LonBs, ClpPBs, and ClpXBs proteases from B. subtilis was analyzed. Additionally, we showed that purified Zeta toxin protects the Epsilon protein from rapid ClpXP-catalyzed degradation.

Modified toxin-binding inhibition (ToBI) test for epsilon antitoxin determination in serum of immunized rabbits.

Abstract: The aim of the present study was to evaluate and standardize the ToBI test in vitro as a substitute for the serum neutralization test in mice for quality control of clostridial vaccines. The ToBI test in vitro was used to evaluate 40 serum samples of known antibody content, obtained from rabbits immunized against clostridiosis with experimental vaccine. The correlation between epsilon antitoxin titers in rabbit sera, determined by the ToBI test and serum neutralization in mice, ranged from 0.222% to 0.452% in polyvalent vaccines and from 0.154% to 0.387% in monovalent vaccines. Interplate coefficients of variation were not significant, reaching 0.350% in polyvalent vaccines and 0.400% in monovalent vaccines, indicating high homogeneity. In conclusion, the ToBI test in vitro is suitable for assessing the potency of clostridial vaccines and may be used as an alternative method able to replace current in vivo tests.

Identification and functional characterization of a bacterial homologue of Zeta toxin in Leishmania donovani.

Abstract: Zeta-toxin is a cognate toxin of epsilon antitoxin of prokaryotic Type II toxin-antitoxin system (TA) and play an important role in cell death. An orthologue of bacterial-zeta-toxin (BzT) was identified in Leishmania donovani with similar structural and functional features. Leishmania zeta-toxin (named Ld_ζ1) harboring similar UNAG and ATP-binding pockets showed UNAG kinase and ATP-binding activity. An active Ld_ζ1 was found to express in infective extracellular promastigotes stage of L. donovani and episomal overexpression of an active Ld_ζ1domain-triggered cell death. This study demonstrates the presence of prokaryotic-like-zeta-toxin in eukaryotic parasite Leishmania and its association with cell death. Conceivably, phosphorylated UNAG or analogues, the biochemical mimics of zeta-toxin function mediating cell death can act as a novel anti-leishmanial chemotherapeutics.

Control of Clostridium perfringens vaccines using an indirect competitive ELISA for the epsilon toxin component - examination of the assay by a collaborative study.

Abstract: Investigations on the replacement of the mouse neutralisation test for proving vaccine batches of Clostridium (C.) perfringens toxoid vaccines were performed since several years. The European Pharmacopoeia (Ph. Eur.) monograph Clostridium perfringens vaccines for veterinary use (0363) is prescribing a potency test by immunisation of rabbits and checking the induction of specific antibodies against the toxins in a mouse neutralisation test. Since the monograph was revised, immunochemical methods are favoured to detect directly specific antibodies in the rabbit sera. An indirect competitive ELISA using a monoclonal antibody was established at the Paul-Ehrlich-Institut for the detection of antibodies against the epsilon toxin component of C. perfringens. It was revised using the Clostridia rabbit antiserum Ph. Eur. Biological Reference Preparation (BRP) Batch 1 as reference serum. With a defined content of 11 International Units (IU) of C. perfringens epsilon antitoxin this reference serum enables the calculation of the potency of rabbit sera under test. For the collaborative study vaccine products of different composition licensed for the German and European markets were used. Seven international laboratories were included. Aim was to make a prediction on the transferability and precision of the test method. The results showing a satisfactory intermediate precision and transferability of the test confirmed the applicability of the ELISA method for the batch control of C. perfringens vaccines. Therefore a replacement of the mouse neutralisation test is available.

Serological evaluation of polyvalent commercial vaccines against enterotoxemia in goats

Abstract: We evaluated the serological response of five commercial polyvalent vaccines containing epsilon toxoid of Clostridium perfringens type D. For this, 84 young goats were randomly divided into six groups, with 14 animals in each group. The goats in the control group were not vaccinated, while goats of Groups 1 to 5 received two vaccine shots four weeks apart. The first shot was administered when the goats were 45 (± 3) days old and the second at 75 (± 3). Blood samples for serological tests were collected on days zero, and 30, 60, 90, 120 and 150 after the start of the experiment. The Indirect ELISA technique was used to quantify the epsilon antitoxin antibodies for Clostridium perfringens type D. In general, the mean serum antibody titers of goats on day 60 increased as a response to the two vaccine shots received on days zero and 30. The largest number of animals considered protected was also detected on day 60, in response to the two vaccine shots. Only five animals from Group 1 and one goat from Group 3 displayed antibody titers that are considered protective up to 150 days after vaccination. Based on these results, we concluded that the evaluated vaccines showed poor ability of stimulate a protective immune response in the assessed goats.