Clostridium perfringens α and ß recombinant toxoids in equine immunization / Toxóides recombinantes α e ß de Clostridium perfringens na imunização de equinos

Clostridium perfringens is considered one of the main causative agents of superacute enterocolitis, usually fatal in the equine species, due to the action of the ß toxin, and is responsible for causing severe myonecrosis, by the action of the α toxin. The great importance of this agent in the equine economy is due to high mortality and lack of vaccines, which are the main form of prevention, which guarantee the immunization of this animal species. The aim of this study was to evaluate three different concentrations (100, 200 and 400µg) of C. perfringens α and ß recombinant toxoids in equine immunization and to compare with a group vaccinated with a commercial toxoid. The commercial vaccine was not able to stimulate an immune response and the recombinant vaccine was able to induce satisfactory humoral immune response in vaccinated horses, proving to be an alternative prophylactic for C. perfringens infection.(AU)

Clostridium perfringens é considerado um dos principais agentes causadores de enterocolites superagudas, geralmente fatais na espécie equina, devido à ação da toxina ß, além de ser responsável por causar quadros graves de mionecrose, pela ação da toxina α. A grande importância desses agentes na equinocultura, deve-se a elevada mortalidade e a inexistência de vacinas, principal forma de prevenção, que garantam a imunização dessa espécie animal. O objetivo deste trabalho foi avaliar três diferentes concentrações (100, 200 e 400µg) dos toxóides recombinantes α e ß de C. perfringens na imunização de equinos, bem como comparar com um grupo vacinado com um toxóide comercial. A vacina comercial não se mostrou capaz de estimular uma resposta imune e a vacina recombinante foi capaz de induzir resposta imune humoral satisfatória em equinos vacinados, provando ser uma alternativa profilática para infecção por C. Perfringens.(AU)

Evaluation of Potency on Diphtheria and Tetanus Toxoid for Adult Vaccines by In Vivo Toxin Neutralization Assay Using National Reference Standards

OBJECTIVES: Vaccinations against diphtheria and tetanus are essential in providing immunity against these bacterial infections. The potency of diphtheria and tetanus toxoid vaccines can be measured using the in vivo toxin neutralization assay. The limit of potency of this assay was determined only for children. Therefore, we assessed the potency of adult vaccines using this assay to identify the feasibility of limit for adult vaccines. METHODS: Fifteen lots of tetanus-reduced diphtheria and tetanus-diphtheria-acellular pertussis vaccines were used. In vivo toxin neutralization and lethal challenge assays were conducted on each vaccine to calculate the potencies of the toxoids. National reference standards for toxins and antitoxins were used for in vivo toxin neutralization assay. RESULTS: All 15 lots satisfied the limits of potency for lethal challenge assay. The potency of diphtheria and tetanus toxoids exceeded 1 and 8 units/mL, respectively, for in vivo toxin neutralization assay. CONCLUSION: Although additional studies are required for new assays and limits, the current level of potency for adult vaccines as determined by in vivo toxin neutralization assay, was demonstrated in this study. Such efforts to improve assays are expected to promote the development of diphtheria and tetanus vaccines for adults and to contribute to vaccine self-sufficiency.

Immunogenicity of MenACWY-CRM in Korean Military Recruits: Influence of Tetanus-Diphtheria Toxoid Vaccination on the Vaccine Response to MenACWY-CRM

The quadrivalent meningococcal conjugate vaccine (MenACWY-CRM) has been introduced for military recruits in Korea since 2012. This study was performed to evaluate the immunogenicity of MenACWY-CRM in Korean military recruits. In addition, the influence of tetanus-diphtheria toxoids (Td) vaccination on the vaccine response to MenACWY-CRM was analyzed. A total of 75 military recruits were enrolled. Among them, 18 received a dose of MenACWY-CRM only (group 1), and 57 received Td three days before MenACWY-CRM immunization (group 2). The immunogenicity of MenACWY-CRM was compared between the two groups. The serum bactericidal activity with baby rabbit complement was measured before and three weeks after immunization against serogroups A, C, W-135, and Y. The geometric mean titers (GMTs) against four serogroups were significantly increased in both groups after immunization. Compared to group 2, group 1 exhibited significantly higher vaccine responses in several aspects: post-immune GMTs against serogroup A and C, seroresponse rates against serogroup A, and a fold increases of titers against serogroup A, C, and Y. MenACWY-CRM was immunogenic against all vaccine-serogroups in Korean military recruits. Vaccine response to MenACWY-CRM was influenced by Td administered three days earlier.

Immunogenicity of MenACWY-CRM in Korean Military Recruits: Influence of Tetanus-Diphtheria Toxoid Vaccination on the Vaccine Response to MenACWY-CRM

The quadrivalent meningococcal conjugate vaccine (MenACWY-CRM) has been introduced for military recruits in Korea since 2012. This study was performed to evaluate the immunogenicity of MenACWY-CRM in Korean military recruits. In addition, the influence of tetanus-diphtheria toxoids (Td) vaccination on the vaccine response to MenACWY-CRM was analyzed. A total of 75 military recruits were enrolled. Among them, 18 received a dose of MenACWY-CRM only (group 1), and 57 received Td three days before MenACWY-CRM immunization (group 2). The immunogenicity of MenACWY-CRM was compared between the two groups. The serum bactericidal activity with baby rabbit complement was measured before and three weeks after immunization against serogroups A, C, W-135, and Y. The geometric mean titers (GMTs) against four serogroups were significantly increased in both groups after immunization. Compared to group 2, group 1 exhibited significantly higher vaccine responses in several aspects: post-immune GMTs against serogroup A and C, seroresponse rates against serogroup A, and a fold increases of titers against serogroup A, C, and Y. MenACWY-CRM was immunogenic against all vaccine-serogroups in Korean military recruits. Vaccine response to MenACWY-CRM was influenced by Td administered three days earlier.

Evaluation of humoral immunity and protective efficacy of biofilm producing Staphylococcus aureus bacterin-toxoid prepared from a bovine mastitis isolate in rabbit

Mastitis is a one of the major diseases of dairy animals. Staphylococcus aureus is the most common microorganism associated with this dairy scourge. Cure rates of mastitis associated with this pathogen are appallingly low. Biofilm is an important virulence factor and immunogenic structure of S. aureus that makes it resistant to phagocytosis and antibiotics. Reports on the efficacy of vaccine prepared from a biofilm producing S. aureus are infrequent. The present study was designed to evaluate the role of a bacterin-toxoid prepared from a strong biofilm producing S. aureus in effective immunization of rabbits. The strong biofilm producing S. aureus selected from 64 isolates of staphylococci was used to prepare bacterin-toxoid and aluminum hydroxide gel was added as an adjuvant. The vaccine was evaluated in rabbits by challenge protection assay and humoral immune response. The mortality rates in control and vaccinated groups were 80% and 10% at day 7 post challenge and 100% and 20% at day 15 post challenge, respectively. Serum antibody titer [GMT] was significantly higher [294.0] in vaccinated group as compared to control group of rabbits [2.63] at day 45. The results showed that the vaccine has significantly elicited humoral immune response in rabbit and developed protective efficacy against new infections

ELISA and modified toxin-binding inhibition test for quality control of the clostridial vaccine processes / ELISA direto e ToBI-test modificado para o controle de qualidade de processos de vacinas clostridiais

This study aimed to assess and standardize the ELISA and modified ToBI test in vitro methods in order to verify the potency of epsilon toxicoid in comparison with the in vivo TCP method. The following epsilon toxoids were used: NIBSC standard from batches 375/07, 532/08, 551/08, 373/07 and 378/07. These were evaluated using a TCP test, ELISA and ToBI tests. The results indicate that the correlation ratio between the dilutions of standard NIBSC toxicoid and absorbance values of 89.44% obtained with the ELISA method support the use of the curve to evaluate epsilon toxoids. However, it was observed that the absorbance values were similar for all toxoids, thus presenting no significant difference between higher and lower concentration toxoids. For the ToBI test, the correlation ratio of 96.76, obtained in the curve pattern, demonstrates the effectiveness of the curve to be used in the epsilon toxoid evaluation. The correlation ratio between the titration degrees of toxoids obtained through TCP and ToBI tests was higher than 90%. It is concluded that the type of ELISA test used does present discriminative power for toxoids with different concentrations, which does not support the use of this technique for such a purpose. The ToBI test can be used as a screening method for it is sensitive and effective to detect epsilon toxicoid produced by C. perfringens type D...

Teve-se por objetivo avaliar e padronizar as metodologias in vitro, ELISA e ToBI-test modificado, para a análise de toxoide épsilon, em comparação com a metodologia in vivo TCP. Foram utilizados os seguintes toxoides épsilon: padrão NIBSC e os lotes 375/07, 532/08, 551/08, 373/07 e 378/07, os quais foram avaliados por métodos in vivo, TCP, e in vitro, ELISA e ToBI-test. A análise do título de toxoide épsilon por meio dos métodos in vitro foi realizada a partir de uma curva-padrão, estabelecida previamente. Os principais resultados mostram que os valores de absorbância foram semelhantes para todos os toxoides, não apresentando diferença significativa entre os toxoides mais concentrados e menos concentrados. No ToBI-test, o coeficiente de correlação de 96,76%, obtido na curva-padrão, demonstra a eficiência da curva para avaliação do toxoide épsilon. O coeficiente de correlação entre os títulos de toxoide obtidos pelo TCP e ToBI-test foi superior a 90%. Conclui-se que o tipo de ELISA utilizado não apresenta poder discriminativo para toxoides com diferentes concentrações, inviabilizando a técnica para esse fim. O ToBI-test pode ser utilizado como um método de triagem sensível e eficaz para a detecção de toxoide épsilon de C. perfringens tipo D...

Life-Threatening Acute Fulminant Myocarditis Following a Coffee Diet Program / 대한구급학회지

Myocarditis is an inflammatory disease of the myocardium caused by various infectious or noninfectious triggers. Although viral infections are important causes of myocarditis, some drugs or toxins can also cause myocarditis. We report a case of life-threatening fulminant myocarditis which followed an extensive coffee diet program. Despite medical treatment, the patient was not able to maintain hemodynamic stability. She was supported by extracorporeal membrane oxygenation and completely recovered 3 months later.

Quimioterápicos y cardiotoxicidad: un enfoque actual y práctico para el clínico de una disciplina en pleno desarrollo / Chemotherapy agents and cardiotoxicity: a current and user-friendly approach for the clinician, a developing discipline

La cardiotoxicidad por fármacos quimioterápicos es un efecto adverso frecuente y esperado. En este sentido se ha creado una especialización, la cardiooncología, que tiene como principal objetivo la prevención de estos efectos. La forma de expresión de este fenómeno es muy variada, pudiendo manifestarse como: insuficiencia cardíaca, hipertensión arterial, eventos coronarios agudos y/o trastornos del ritmo. La clave en la prevención está en la idividualización del riesgo cardiotóxico de cada paciente (en base a factores reconocidos como edad, sexo, irradiación mediastinal previa, tipo de fármaco, dosis acumulada, cardiopatía asociada previamente) y el riesgo potencial cardiotóxico de cada quimioterápico. En este sentido se han creado algoritmos de actuación fundamentados en la monitorización y el inicio de tratamiento precoz y oportuno de cada efecto, previniendo el mal mayor en cada paciente.

Resposta humoral de bovinos vacinados contra as toxinas botulínicas tipos c e dem diferentes faixas etárias / Humoral response of vaccinated cattle against toxins of Clostridium botulinum types c and d at different ages

Foi verificada pelo teste de ELISA indireto a resposta humoral contra os toxoides botulínicos C e D em bovinos de diferentes idades. O estudo envolveu 90 animais, que foram divididos em três grupos (n = 30), de acordo com a sua faixa etária; inferior a 2 anos de idade (G1), entre 2 e 5 anos (G2) e superior a 5 anos (G3). Os grupos experimentais foram vacinados com duas doses de vacina antibotulínica bivalente (C e D) comercial, nos dias 0 e 42 após a primo-vacinação (booster). Na avaliação, quando realizada 30 dias após o booster, os animais do G3 apresentaram maior produção de anticorpos (p < 0,05) em relação aos demais grupos. Entre o G1 e G2 não houve diferença significativa na resposta humoral contra a toxina C, no entanto, contra a toxina D, os animais do G1 apresentaram maior produção de anticorpos. Todos os grupos produziram uma resposta significativa de anticorpos contra as toxinas botulínicas após a 2ª dose da vacina bivalente comercial, principalmente contra o tipo D.

Humoral response of vaccinated cattle against toxins of clostridium botulinum types C and D at different ages. Cattle humoral response against type C and D botulinum toxoids (indirect ELISA) was verified in animals of different ages. The animals (n = 90) were divided in three groups (n = 30): group one (G1): less than two years old; group two (G2): from 2 to 5 years old; group three (G3): more than 5 years old. The groups were vaccinated with two doses [0 and 42 days after primary vaccination (booster)] of bivalent (C and D) antibotulinum vaccine. Group three had higher antibody production (p ≤ 0.05) compared to the other groups, 30 days after the booster. There was no difference (G1 and G2; p ≥ 0.05) in the humoral response against C toxin, however, against D toxin, group one had higher antibody production. It was possible to conclude that after two doses of the commercial bivalent vaccine all groups produced a significant antibody response against botulinum toxins, especially against D type.

Neuropatías de fibras pequeñas de origen tóxico: [revisión] / Small fiber neuropathies of toxic origin: [review]

La neurona sensorial de fibras pequeñas se encarga de la función termoalgésica y autonómica, función que se ve afectada por procesos tóxicos, mediados por sustancias como la del alcohol o por medicamentos antineoplásicos, biológicos o inmunoreguladores, en los que se comprometen en gran medida los factores neutróficos que soportan o mantienen a las estructuras neuronales sensoriales. Estas sustancias penetran en las neuronas sensoriales en los ganglios de las raíces dorsales, que carece de barrera protectora afectan especialmente a los factores de crecimiento neural (NGF), y de crecimiento neural derivado del cerebro BDNF, que son los encargados de restaurar y mantener las estructuras que median sus acciones a través de sustancia P y acetilcolina, de allí su sintomatología de dolor quemante y de los cambios autonómicos. Esta toxicidad varía en gran medida por la concentración de las sustancias en el ganglio de la raíz dorsal o por las alteraciones que se originan en las mitocondrial por disregulación en la homeostasis del calcio o de procesos asociados. También se puede presentar compromiso en las subunidades de las beta-tubulinas de las axones que se comprometen en la división celular y en la apoptosis, originando compromiso en el transporte axonal. Una estrategia terapéutica es la prevención de estas complicaciones o la supresión de la sustancia, lo cual debe revertir el proceso. La administración de factores neurotróficos puede prevenir o tratar estas complicaciones, una manera más racional es la corrección de las deficiencias nutricionales, sustancias esenciales para la toxicidad de medicamentos función de estas estructuras con la administración de oligoelementos de calcio y magnesio, previa y posteriormente a la administración de medicamentos con reconocida toxicidad en los nervios de fibras pequeñas.

In vitro evaluation of Clostridium septicum alpha toxoid / Avaliação in vitro de toxoide alfa de Clostridium septicum

Aiming to investigate in vitro alternatives, a test for neutralizing antibody detection using cell culture was developed. This test was more sensitive than previous animal models, allowing for detection of substantially lower alpha toxin and anti-alpha toxin titers. Titers observed during in vivo and in vitro seroneutralization had a correlation of 99.12 percent, indicating that cell culture is a viable alternative in the evaluation of vaccine potency, screening of vaccinal seeds, and Clostridium septicum alpha toxin titration.

Padronizou-se um teste para detecção de anticorpos neutralizantes in vitro, em cultura de células. O modelo in vitro mostrou-se mais sensível que os testes com animais, permitindo a detecção de títulos de toxina e antitoxina alfa mais baixos. Os títulos observados na soroneutralização in vivo e in vitro, apresentaram correlação de 99,12 por cento, demonstrando ser a cultura de células uma alternativa viável na avaliação da potência de vacinas, triagem de sementes vacinais e titulação de toxina alfa de Clostridium septicum.

Cloning and expression of a hemolysin gene of Aeromonas hydrophila and the immunogenicity of the toxoid / 生物工程学报

According to the GenBank sequences (GenBank Accession No. AF539467), one pair of primers was designed to amplify hly gene of Aeromonas hydrophila by PCR. After sequencing, homology analysis indicated that a DNA fragment of 1485 bp was amplified from isolated DNA from Aeromonas hydrophila, and it shared more than 99% homology in nucleotide sequence compared with other reference strains in GenBank. The gene was cloned in pET-28a vector to construct a recombinant plasmid pET-28a-hly, which was transformed into Escherichia coli BL21 (DE3), and the recombinant strain BL21(DE3)(pET-28a-hly) was obtained. The hemolysin was highly expressed when the recombinant strain BL21 (DE3) (pET-28a-hly) was induced by IPTG. The expressed protein was 56 kD as estimated by 15% SDS-polyacrylamide gel electrophoresis (SDS-PAGE). The immunogenicity of the expressed Hly protein was confirmed by Western blotting. Mice were immunized with inactivated whole bacteria vaccine and the genetic engineering vaccines showing promise that all these vaccines have a high protective ability. The results showed that the recombinant strain BL21 (DE3)(pET-28a-hly) could be candidate of hemolysin toxoid vaccine to provide protective immunity against diseases caused by Aeromonas hydrophila.

new brevifolin carboxylic acid derivative from lagerstroemia indica L.: isolation, characterization and antibacterial activity

A new polyphenolic, 1-O-brevifolin carboxylyl-beta-[4]C1 glucopyranose 5, together with four known phenolics, 2,6-di-O-galloyl- beta -[4]C1-glucopyranose 1, vescalagin 2, castalagin 3 and 3, 4, 8, 9, 10-pentahydroxydibenzo [b, d] pyran-6-one 4 have been isolated from the aqueous alcohol extract of the leaves of Lagerstroemia indica L. All structures were established on the basis of analysis of [1]H, [13]C NMR, HMQC, HMBC and ESI-MS spectral data. The extract as well as the isolates 1-5 showed considerable antibacterial activity against drug-resistant bacterial strains

Comparison of protection induced by corynebacterium pseudotuberculosis toxoid and BCG vaccines in lambs

A total of 460 sheep in 3 distinct age/sex groups were examined to determine the occurrence of caseous lymphadenitis in Beni Suef Governorate. The results confirmed that frequency increased with age but also revealed increases in extent of involvement and occurrence of visceral lesion, particularly in association with lesion in the body. An attempt was conducted to evaluate the immunogenic value of toxoid [prepared from C. pseudotuberculosis field isolate] and BCG used in sheep farms. Application of ELISA revealed slight increase in antibody response to toxoid and BCG vaccines prior to challenge, however, at week 7 [1 week post challenge] there was statistical significance elevation of antibody titre in group A vaccinated with toxoid over group B vaccinated with BCG [P < 0.05]. The capacity for induction of memory is a better indicator of vaccine performance and is most effectively assessed by challenge in the natural host. The protection rates post challenge were 71.4%, 42.9% and 14.3% for lambs immunized with toxoid, BCG and non vaccinated group respectively. Generally, the toxoid vaccine [prepared from field isolate] has been shown to confer high but not absolute degree of protection against caseous lymphadenitis and was more efficient than BCG. In sheep, it is likely that a short period of expression is insufficient to induce strong immune response in vivo

The study on the cloning and expression of alpha toxin gene of clostridium septicum and the immunity of the toxoid / 生物工程学报

In order to amplify alpha toxin gene of Clostridium septicum HeB01 strain, one pair of primers was designed according to the GenBank sequence, and a 1323bp alpha toxin gene fragment was obstained by PCR. Sequence analysis indicated that the homology of the nucleotid sequence of HeB01 strain to those other reference strains was more than 99.5% . The expression plasmid pQE30-alpha was constructed by inserting alpha toxin gene into the prokaryotic expression vector pQE30. The plasmid expressed when the recombinant strain M15(pQE30-alpha) was induced by IPTG. The specific 48 kD protein was detected SDS-PAGE and the immunogenicity of the expressed alpha toxin was confirmed by Western blot and ELISA. The expressed alpha toxin was transformed into alpha toxoid vaccine by adding 0.3% formaldehyde into alpha toxin. The protective immune response was proved after the mice was immunized with alpha toxoid vaccine. The results showed that the recombinanted strain M15 (pQE30-alpha) could be as a candidate of alpha toxoid vaccine to provide protective immune response against clostridium septicum infection.

Protective efficacy of maternal antibodies induced by Salmonella toxoid (vaccine).

An attempt was made to evaluate the protective efficacy of maternal antibodies in chicks against salmonellosis. Layer chicks ageing 21 days were individually vaccinated with 100 microg of Salmonella enterica subspecies enterica serovar Weltevreden (BM 1643) toxoid adjuvanted with vitamin E subcutaneously. After 90 days of the primary vaccination the birds were given booster dose of the vaccine. The saline extract of the yolk of eggs laid by the vaccinated birds yielded agglutination and ELISA titres ranging from 43.2 +/- 5.33 to 75.2 +/- 6.26 and 4.987 x 10(3) +/- 0.54 to 5.89x103 +/- 0.56, respectively. Sera of chicks hatched from eggs laid by the vaccinated layers were also subjected to agglutination and ELISA. Agglutination and ELISA titres on the 5th day--post hatching (dph) were 21.6 +/- 1.75 and 4.025 x 10(2) +/- 0.59, while on the 10th dph titers were 13.6 +/- 1.65 and 1.21 x 10(2) +/- 0.60, respectively. It was also observed that only one out of 6 chicks died when challenged with 2 x 10(9) CFU of S. serovar Gallirarum at the age of 7 days showing 83.33% protection. Thus it can be concluded that passive immunity confided by Salmonella enterica subspecies enterica serovar Weltevreden (BM 1643) toxoid can protect chicks against salmonellosis during their early days of life.

Reimmunization after bone marrow transplantation: current recommendations and perspectives

Pacientes submetidos ao transplante de medula óssea, alogênico ou autogênico, perdem sua memória imunológica de exposição a agentes infecciosos e a vacinas adquiridas durante sua vida e necessitam eventualmente serem revacinados. Toxóide difteriano, tetânico e pertussis (crianças < de 7 anos), Haemophilus influenza do tipo B (Hib) conjugada, polissacáride pneumocócica - valência 23, vacina inativada de influenza, vacina de pólio inativada e vacinas vivas atenuadas de sarampo-caxumba- rubéola são as vacinas comumente recomendadas em um programa de vacinação de TMO. No entanto, o momento, número de doses e/ou o tempo de duração da imunidade após a vacinação ainda não se encontram estabelecidos. Os protocolos de vacinação entre os vários centros de TMO variam e inexistem dados que propiciem sólidas recomendações. O uso de outras vacinas e perspectivas de diferentes protocolos de vacinação são discutidos nesta revisão.

Perfil sorológico das amostras de Clostridium botulinum tipos C e D utilizadas para produçäo de imunógenos no Brasil / Serological profile of C and D type Clostridium botulinum strains used for toxoid production in Brazil

Com o objetivo de avaliar o perfil sorológico de três amostras de Clostridium botulinum tipo C e três do tipo D utilizadas para produçäo de imunógenos no Brasil, determinou-se o índice de eficiência e o grau de homologia sorológica dentro de cada tipo. O índice de eficiência mostrou a mesma tendência para os dois tipos. Os consumos relativos de antitoxinas foram proporcionais nos níveis de 20, 200 e 1000 DL50, verificados através de curvas de neutralizaçäo que apresentaram inclinaçöes semelhantes. A quantificaçäo da variaçäo do consumo de antitoxinas expresso em grau de homologia sorológica reflete uma similaridade relativa entre as amostras, sendo neutralizados 80 a 91,5 por cento de determinantes antigênicos para o tipo C e 85 a 95 por cento para o tipo D. Pelos resultados apresentados, as amostras analisadas comportaram-se como variantes sorológicas nos níveis de testes de 20, 200 e 1000 DL50

Induction of neutralizing antibodies in mice immunized with scorpion toxins detoxified by liposomal entrapment

The possibility of producing neutralizing antibodies against the lethal effects of scorpion toxins was evaluated in the mouse model by immunization with an immunogen devoid of toxicity. A toxic fraction (5 mg) from the venom of the scorpion Tityus serrulatus was entrapped in sphingomyelin-cholesterol liposomes. The liposomes were treated for 1 h at 37 degrees Celsius with a 1 per cent (w/w) trypsin solution in 0.2 M sodium carbonate buffer, pH 8.3. This treatment led to a strong reduction in venom toxicity. Immunization was performed as follows: mice were injected sc with 20 mug of the liposome-entrapped toxic fraction on days 1 and 21 and a final injection (20 mug) was administered ip on day 36. After injection of the immunogen, all mice developed an IgG response which was shown to be specific for the toxic antigen. The antibodies were measured 10 days after the end of the immunization protocol. In an in vitro neutralization assay we observed that pre-incubation of a lethal dose of the toxic fraction with immune serum strongly reduced its toxicity. In vivo protection assays showed that mice with anti-toxin antibodies could resist the challenge with the toxic fraction, which killed, 30 min after injection, all non-immune control mice.

Gamma irradiation of Egyptian cobra [Naja haje] venom

The aim of the present study was to prepare an effective and safe toxoid for the Egyptian Cobra [Naja haje] Venom by gamma irradiation. The effects of gamma irradiation [0.1-10 M rad] on the toxicity, as well as the antigen antibody complex formation reactivity was described. It appears from the results that the lethality of Naja haje venom irradiated in the dry form was not affected up to a dose of 10 M rad [100 KGy]. On the other hand the venom irradiated in the aqueous solution form showed a decrease in its lethality, and this was proportionately related to the dose of irradiation, while the ability of the venom antigens to react with its corresponding antibodies was retained up to irradiation dose of 5 M rad. The results of double immunodiffusion of non irradiated and the different dose levels of gamma irradiated venom [0.1-5 M rad] against a commercial Egyptian poly valent antivenin, all showed similar patterns the four visible lines obtained in the immunodiffusion reactions were identical and joined smoothly at the corners, indicating that there was no change in antigenic reactivity with antibodies determinants