Tetanus toxin L chain is processed by major histocompatibility complex class I and class II pathways and recognized by CD8+ or CD4+ T lymphocytes.
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Tetanus toxin (TeNT) is a heterodimeric protein antigen, whose light chain (L) is translocated in the cytosol of neuronal target cells specifically to cleave its substrates, vesicle-associated membrane protein-2 (VAMP-2, or synaptobrevin) or cellubrevin. We report that the L chain behaves as a nominal antigen recognized by specific T-cell clones upon either class I- or II-restricted presentation. Three types of responses are observed: (i) a TeNT- and L-specific CD8+ T-cell response, that can be inhibited in a dose-dependent manner by the proteasome inhibitor clasto-Lactacystin beta-lactone; (ii) a CD4+ T-cell response specific for L but not TeNT, with recognition of a determinant processed in a chloroquine-sensitive and brefeldin A-resistant compartment; (iii) a CD4+ T-cell response against both L and TeNT, with processing in a brefeldin A-sensitive compartment. The L chain processing was investigated in U937 cells by internalization and localization of L chain by separation of the cell content by differential centrifugation experiments. After incubation with TeNT or L chain in the presence of H chain, the L chain was predominantly distributed in the cytosolic fraction, whereas incubation with L alone led to localization in a lysosome/membrane fraction. The distribution of the TeNT L chain in both cytosolic and endocytic compartments of the antigen-presenting cell accounted for its processing by both class I and class II pathways. Furthermore, an epitope overlapping with the zinc-binding region was recognized by CD4+ and CD8+ T cells. (+info)
A defined medium for the growth of Clostridium tetani and other anaerobes of clinical interest.
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The growth of six strains of Clostridium tetani was assessed in a chemically supplemented commercially available defined medium. All strains grew reliably even after 12 serial passages, and two strains produced demonstrable toxic activity after passage. Consistent growth of the test strains could also be obtained on a solid version of this medium ("CA109-S" medium), and the strains could be serially passaged on this medium. Preliminary evidence is presented that the medium supports the surface growth of some other test anaerobes. Such a defined solid medium might prove of value in further studies on the surface growth of C. tetani and of other anaerobes of clinical interest. (+info)
Isolation and purification of two antigenically active, "complimentary" polypeptide fragments of tetanus neurotoxin.
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Tetanus neurotoxin (molecular weight approximately 160,000) was purified from bacterial extracts (intracellular toxin) and mildly trypsinized and from culture filtrates (extracellular toxin). Both purified preparations could be dissociated reversibly into two polypeptide chains, with molecular weights of 53,000 (fragment alpha) and 107,000 (fragment beta), by treatment with 100 mM dithiothreitol (DTT) and 4 M urea with concomitant loss of toxicity. Upon removal of DDT and urea from the dissociated toxin preparation by dialysis, these fragments reassociated, forming the whole toxin. The two fragments were isolated and purified from the dissociated toxin by gel filtration on an Ultrogel AcA 44 column equilibrated with buffer containing 2 M urea and 1 mM DTT. The preparation of fragment alpha was nontoxic whereas that of fragment beta was slightly toxic. Immunodiffusion analyses, using horse antitoxin, showed that the antigenicities of fragment alpha and fragment beta were distinct from each other but were partially identical with that of undissociated toxin. The abilities of these fragments to precipitate antitoxin were lost on heating at 60 C for 5 min. The molecular substructure of tetanus neurotoxin is discussed on the basis of these findings. (+info)
Safety and immunogenicity of a new equine tetanus immunoglobulin associated with tetanus-diphtheria vaccine.
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In a single-center double-blind, randomized trial in West Africa, we evaluated the safety and immunogenicity of a new pasteurized, pepsin-digested equine tetanus immunoglobulin (heat-treated equine tetanus immunoglobulin [HT-ETIG]) in the post-exposure prophylaxis of tetanus compared with the reference product, equine tetanus immunoglobulin (ETIG). A total of 134 adults presenting to Garoua Hospital, Cameroon with a tetanus-prone wound were randomized to receive a 3,000 international units (IU) intramuscular injection (deltoid) of either HT-ETIG or ETIG, simultaneously with a tetanus-diphtheria vaccine. No serious adverse reactions were reported. The incidences of local and systemic reactions were similar in the two groups. Repeated measures of equine tetanus-antibody levels measured from Day 0 to Day 28 showed that titers were significantly higher in the HT-ETIG group (P = 0.017). At Day 7, a higher percentage of subjects in the HT-ETIG group had equine antibody levels > or = 0.1 IU/ml (80.4% versus 37.9%; P < 0.0001). No cases of tetanus occurred during the follow-up, attesting to the efficacy of the combined prophylactic treatment. (+info)
Protection against tetanus by needle-free inoculation of adenovirus-vectored nasal and epicutaneous vaccines.
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The effectiveness of vaccination programs would be enhanced greatly through the availability of vaccines that can be administered simply and, preferably, painlessly without the need for timed booster injections. Tetanus is a prime example of a disease that is readily preventable by vaccination but remains a major threat to public health due to the problems associated with administration of the present vaccine. Here we show that a protective immune response against live Clostridium tetani infection in mice can be elicited by an adenovirus vector encoding the tetanus toxin C fragment when administered as a nasal or epicutaneous vaccine. The results suggest that these vaccination modalities would be effective needle-free alternatives. This is the first demonstration that absorption of a small number of vectored vaccines into the skin following topical application of a patch can provide protection against live bacteria in a disease setting. (+info)
Antibody responses to vaccinations given within the first two years after transplant are similar between autologous peripheral blood stem cell and bone marrow transplant recipients.
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As a consequence of the significantly larger inoculum of lymphoid cells present in peripheral blood stem cell (PBSC) harvests compared to bone marrow (BM), it is possible that autoPBSCT recipients may have an earlier and*or enhanced response to vaccines. Until data to confirm this become available, the European Blood and Marrow Transplantation Association (EBMT) recommend that all transplant recipients be immunized in the same way regardless of stem cell source. We performed a prospective study comparing serological responses to influenza, pneumococcal polysaccharide and tetanus toxoid vaccines between autoPBSCT with autoBMT recipients. Antibody responses in sibling HLA-matched allogeneic BMT (alloBMT) survivors were also evaluated. All vaccines were administered within the first 2 years after stem cell transplantation. Fifty patients were enrolled. The time of vaccination after transplant was similar between autoPBSCT (mean 11 months for each vaccine) and autoBMT recipients (mean 12 months except 13 months for tetanus toxoid) (P = NS). Serological responses were poor and no significant difference in response to any of the vaccines used was seen between the three transplant cohorts. We provide no evidence that current EBMT guidelines be modified. Large prospective vaccine studies are needed to address the issue more fully. (+info)
Chronic ulcers and myasis as ports of entry for Clostridium tetani.
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Evaluating tetanus immune status is not yet the usual clinical practice regarding patients with chronic ulcers or myasis. However, of 858 tetanus patients at Hospital Couto Maia (Salvador, Bahia, Brazil) aged 1 year or above, 2 had pressure ulcers and 17 had chronic ulceration of the lower limbs where these skin lesions were the ports of entry for Clostridium tetani. In these 19 cases, the following predisposing factors were described: venous insufficiency (n=6), sickle cell anemia (n=2), Hansen s disease (n=1), malnutrition (n=1), diabetes mellitus (n=1), trauma (n=1) and unknown factors (n=7). In 6 other cases, in addition to the Hansen s disease patient, the port of entry for tetanus was the site of extraction of Tunga penetrans larvae. In these 25 cases, the majority of patients (68%) were over 40 years old (17/25) and all of these patients stated that they had either not followed a tetanus toxoid vaccination regimen (19/25), or had partially completed such a regimen, or did not give precise information (6/25). Among the same series studied, over half (52%) of the patients died (13/25). We conclude that tetanus prevention must be included in the treatment of chronic skin ulcer patients, vaccination coverage should be increased among older people, and strategies aimed at improving coverage for all age groups must be reviewed. (+info)
The genome sequence of Clostridium tetani, the causative agent of tetanus disease.
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Tetanus disease is one of the most dramatic and globally prevalent diseases of humans and vertebrate animals, and has been reported for over 24 centuries. The manifestation of the disease, spastic paralysis, is caused by the second most poisonous substance known, the tetanus toxin, with a human lethal dose of approximately 1 ng/kg. Fortunately, this disease is successfully controlled through immunization with tetanus toxoid; nevertheless, according to the World Health Organization, an estimated 400,000 cases still occur each year, mainly of neonatal tetanus. The causative agent of tetanus disease is Clostridium tetani, an anaerobic spore-forming bacterium, whose natural habitat is soil, dust, and intestinal tracts of various animals. Here we report the complete genome sequence of toxigenic C. tetani E88, a variant of strain Massachusetts. The genome consists of a 2,799,250-bp chromosome encoding 2,372 ORFs. The tetanus toxin and a collagenase are encoded on a 74,082-bp plasmid, containing 61 ORFs. Additional virulence-related factors could be identified, such as an array of surface-layer and adhesion proteins (35 ORFs), some of them unique to C. tetani. Comparative genomics with the genomes of Clostridium perfringens, the causative agent of gas gangrene, and Clostridium acetobutylicum, a nonpathogenic solvent producer, revealed a remarkable capacity of C. tetani: The organism can rely on an extensive sodium ion bioenergetics. Additional candidate genes involved in the establishment and maintenance of a pathogenic lifestyle of C. tetani are presented. (+info)