Genetically detoxified tetanus toxin as a vaccine and conjugate carrier protein.

Tetanus toxoid (TTxd), developed over 100 years ago, is a clinically effective, legacy vaccine against tetanus. Due to the extreme potency of native tetanus toxin, manufacturing and regulatory efforts often focus on TTxd production, standardization, and safety, rather than product modernization. Recently, a genetically detoxified, full-length tetanus toxin protein (8MTT) was reported as a tetanus vaccine alternative to TTxd (Przedpelski et al. mBio, 2020). Here we describe the production of 8MTT in Gor/MetTM E. coli, a strain engineered to have an oxidative cytoplasm, allowing for the expression of soluble, disulfide-bonded proteins. The strain was also designed to efficiently cleave N-terminal methionine, the obligatory start amino acid for E. coli expressed proteins. 8MTT was purified as a soluble protein from the cytoplasm in a two-column protocol to > 99 % purity, yielding 0.5 g of purified 8MTT/liter of fermentation broth with low endotoxin contamination, and antigenic purity of 3500 Lf/mg protein nitrogen. Mouse immunizations showed 8MTT to be an immunogenic vaccine and effective as a carrier protein for peptide and polysaccharide conjugates. These studies validate 8MTT as commercially viable and, unlike the heterogenous tetanus toxoid, a uniform carrier protein for conjugate vaccines. The development of a recombinant, genetically detoxified toxin produced in E. coli aligns the tetanus vaccine with modern manufacturing, regulatory, standardization, and safety requirements.

Characterising the Phenotypic Diversity of Antigen-Specific Memory B Cells Before and After Vaccination.

The diversity of B cell subsets and their contribution to vaccine-induced immunity in humans are not well elucidated but hold important implications for rational vaccine design. Prior studies demonstrate that B cell subsets distinguished by immunoglobulin (Ig) isotype expression exhibit divergent activation-induced fates. Here, the antigen-specific B cell response to tetanus toxoid (TTd) booster vaccination was examined in healthy adults, using a dual-TTd tetramer staining flow cytometry protocol. Unsupervised analyses of the data revealed that prior to vaccination, IgM-expressing CD27+ B cells accounted for the majority of TTd-binding B cells. 7 days following vaccination, there was an acute expansion of TTd-binding plasmablasts (PB) predominantly expressing IgG, and a minority expressing IgA or IgM. Frequencies of all PB subsets returned to baseline at days 14 and 21. TTd-binding IgG+ and IgA+ memory B cells (MBC) exhibited a steady and delayed maximal expansion compared to PB, peaking in frequencies at day 14. In contrast, the number of TTd-binding IgM+IgD+CD27+ B cells and IgM-only CD27+ B cells remain unchanged following vaccination. To examine TTd-binding capacity of IgG+ MBC and IgM+IgD+CD27+ B cells, surface TTd-tetramer was normalised to expression of the B cell receptor-associated CD79b subunit. CD79b-normalised TTd binding increased in IgG+ MBC, but remained unchanged in IgM+IgD+CD27+ B cells, and correlated with the functional affinity index of plasma TTd-specific IgG antibodies, following vaccination. Finally, frequencies of activated (PD-1+ICOS+) circulating follicular helper T cells (cTFH), particularly of the CXCR3-CCR6- cTFH2 cell phenotype, at their peak expansion, strongly predicted antigen-binding capacity of IgG+ MBC. These data highlight the phenotypic and functional diversity of the B cell memory compartment, in their temporal kinetics, antigen-binding capacities and association with cTFH cells, and are important parameters for consideration in assessing vaccine-induced immune responses.

Alergia a toxoide tetánico: estudio de 14 casos / Allergy to tetanus toxoid: study of 14 cases

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Oxigenación tisular durante la crisis de disautonomía en el tétano severo / Tissular oxygenation during the crisis of dysautonomia in to severe tetanus

El síndrome de hiperactividad simpática en el marco del tétanos severo, es un cuadro de gravedad extrema por ya ser una de las principales causas de muerte. Fisiopatológicamente continúa siendo un "misterio", tratáse de explicar todo lo que ocurre debido a la elevada concentración de catecolaminas circulantes. Sin embargo, poco se sabe sobre el comportamiento de la oxigenación de los tejidos durante las crisis disautonómicas, dada las dificultades que existen para su diagnóstico, detección precoz y ausencia de literatura al respecto. Por tal motivo nos propusimos evaluar en forma prospectiva los pacientes con tétanos severo sometidos a monitoreo hemodinámico invasivo y de la perfusión del territorio esplácnico, particularmente durante los episodios de sobreactividad del sistema nervioso autónomo. Así, durante 20 crisis disautonómicas desarrolladas en 12 pacientes consecutivos se evidenció una profunda depresión miocárdica e hipoxia tisular, los que pueden constituir factores de riesgo clave que ayuden a explicar la elevada morbimortalidad cuando el síndrome hace su aparición en el marco del tétanos severo (AU)

Oxigenación tisular durante la crisis de disautonomía en el tétano severo / Tissular oxygenation during the crisis of dysautonomia in to severe tetanus

El síndrome de hiperactividad simpática en el marco del tétanos severo, es un cuadro de gravedad extrema por ya ser una de las principales causas de muerte. Fisiopatológicamente continúa siendo un "misterio", tratáse de explicar todo lo que ocurre debido a la elevada concentración de catecolaminas circulantes. Sin embargo, poco se sabe sobre el comportamiento de la oxigenación de los tejidos durante las crisis disautonómicas, dada las dificultades que existen para su diagnóstico, detección precoz y ausencia de literatura al respecto. Por tal motivo nos propusimos evaluar en forma prospectiva los pacientes con tétanos severo sometidos a monitoreo hemodinámico invasivo y de la perfusión del territorio esplácnico, particularmente durante los episodios de sobreactividad del sistema nervioso autónomo. Así, durante 20 crisis disautonómicas desarrolladas en 12 pacientes consecutivos se evidenció una profunda depresión miocárdica e hipoxia tisular, los que pueden constituir factores de riesgo clave que ayuden a explicar la elevada morbimortalidad cuando el síndrome hace su aparición en el marco del tétanos severo

Tetanos post-aborto / Post-abortal tetanus

El tétanos es una enfermedad cuyas manifestaciones clínicas son producidas por las toxinas y no por el germen, caracterizandose por la introducción de clostridium tetáni a un tejido necrótico cuyo medio es satisfactório para este germen anaeróbico estricto. El curso clínico y el pronóstico de esta enfermedad esta dado por el tiempo de incubación (menor de una semana es de mal pronóstico), tiempo de generalización de las contracciones musculares (menor de 24 horas es de pésimo pronóstico), puerta de entrada (inyectables, post-cirugías y post-aborto son de evolución sombría) y presencia de hipertermia o hipotermia marca un curso pobre de la enfermedad. En este estudio se hace una revisión de todos los casos de tétanos presentados en el Hospital Loayza de Marzo de 1971 a Marzo de 1985 y en relación a la erradicación del foco infeccioso para los casos de tétanos post-aborto se adicionó la casuística del Hospital Cayetano Heredia en el mismo periodo. En estas pacientes debe indicarse legrado uterino y sólo excepcionalmente histerectomía. Unido a esta conducta quirúrgica debe seguirse los mismos procedimientos terapéuticos establecidos para otras puertas de entrada al germen. Siguiendo recomendaciones de últimas aplicaciones se ha aplicado gammaglobulina humana antitetánica intratecal en los últimos casos con buenos resultados, aun cuando todavía se trata de observaciones preliminares

[Split tetanus vaccine. Studies on its efficacy and tolerance as compared to adsorbed vaccine]. / Tetanus-Spaltimpfstoff. Untersuchungen über Wirksamkeit und Verträglichkeit im Vergleich zu Adsorbatimpfstoff.

A tetanus split vaccine consisting of the purified C fragment of tetanus toxin was compared with normal adsorbed toxoid vaccine with respect to local reactions and immunogenicity. Altogether, 200 volunteers with primary vaccination against tetanus were vaccinated. Local reactions were studied in 170 persons, the immune response in 87. Immunogenicity, expressed as mean conversion factor, was identical for both groups. Local reactions, including frequency, duration and intensity of symptoms, were reduced by 60% in the subjects given split vaccine. In both groups a positive correlation between preimmunization antibody titer and the mean extent of the local reaction was observed.

Behavioural correlates of an experimental hippocampal epileptiform syndrome in rats.

Experiments are reported describing assessment of abnormal behaviour of rats in which a chronic epileptiform syndrome has been induced by the injection of tetanus toxin bilaterally into their hippocampi. The abnormal behaviour included hyper-reactivity to a novel environment, intermittent aggression on handling, and abnormally passive response to a strange rat introduced into their home cage. In animals with unilateral injection of toxin, electrical records from the hippocampi have been obtained. They illustrated bilaterally simultaneous discharges and also some independence between the two hippocampi. The discharges were accompanied by overt signs of complex partial seizures during the first few weeks of the syndrome but later occurred without motor signs. In this later stage the rats were somewhat resistant to the convulsant effects of pentylenetetrazol.

Histoautoradiography of central nervous system in rats with generalized tetanus due to 125I-toxin.

Rats were injected i.v. with 125I-tetanus toxin. In autoradiographs of the spinal cord radioactivity was found over the pericarya and in the surroundings of the motoneurones whereas grain density was less over their nuclear region. In addition, pericarya in the lateral horn of the thoracic region and also the bipolar cells of the spinal ganglia contained radioactivity. The central part and the dorsal horns of spinal cord, and the white substance did not show any appreciable radioactivity. Within the medulla oblongata, clusters of large cells representing motor nuclei, as well as some fibre tracts close to them, contained 125I. Forebrain and cerebellum remained free. According to its histoautoradiographic appearance, generalized tetanus can be described best as a combination of multiple local tetani.