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1.
In the USA, the potency of commercially prepared equine tetanus antitoxin is determined by the method outlined in the Code of Federal Regulations, Title 9, Part 113.451. In the current test, commercial equine tetanus antitoxin is tested by a toxin neutralization test in guinea pigs. The in vivo test measures antitoxin content through effectiveness of protection of guinea pigs injected with diluted mixtures of antitoxin and a standard toxin. A competitive enzyme-linked immunosorbent assay, designed as an in vitro alternative to the in vivo test, measures antitoxin content based on a competitive reaction between standard or unknown serum and murine monoclonal antibody specific for tetanus toxin. The monoclonal antibody used in the assay delayed death in mouse passive protection studies and reacted with the C fragment of tetanus toxin. No cross-reaction was observed when the antibody was tested with the toxins of Clostridium chauvoei, C. novyi, C. perfringens, or C. sordellii. The in vitro test will measure the antitoxin content of serum samples containing 100-1500 units of antitoxin. Tetanus antitoxin titers obtained by the competitive enzyme-linked immunosorbent assay compared favorably with the toxin neutralization test conducted in guinea pigs. The in vitro assay serves as a feasible alternative to the in vivo test because it can be completed in less time, is reproducible, and eliminates the use of test animals.  相似文献   

2.
Bernard J. F. Perey 《CMAJ》1966,94(9):437-441
Injections of tetanus antitoxin of animal origin frequently cause serious disability and sometimes death. Despite world-wide knowledge of these effects, millions of prophylactic injections of equine tetanus antitoxin are given annually, and it is continually proposed that the dosage be increased in order to obtain higher “protective” levels in the serum, a procedure which would increase the incidence and severity of reactions. Furthermore, equine antitoxin frequently fails to prevent tetanus.Tetanus antitoxin of human origin is available which carries no risk of complications and confers a higher degree of immunity more quickly than equine antitoxin. The cost of treating reactions to horse serum, together with the financial loss incurred by work-absence, far outweighs the cost of human antitoxin. In the author''s opinion, the use, in this country, of antitoxin of animal origin is no longer medically acceptable and may well prove legally indefensible.  相似文献   

3.
Botulinum antitoxin is commonly titrated by injecting a mixture of toxin and antitoxin into mice and by utilizing deaths as a marker to measure the amount of unneutralized toxin. We attempted to titrate antitoxin by converting the severity of symptoms (notably palsy) and time-to-death in days into scores. In neutralization tests with toxin levels at 5.9 LD50 and 23.5 LD50, a linear relationship was obtained for antitoxin dose in a range between 0.03 to 0.003 IU/ml. Statistical analysis showed that homogeneity of variance or slope was not denied for the scores obtained on any day from the first to the fourth days after injection, demonstrating that this method can titrate accurately antitoxin of such a low level as 0.003 IU/ml within 4 days after injection.  相似文献   

4.
Antitoxin in human pertussis immune globulins   总被引:1,自引:0,他引:1  
The level of antitoxin i.e. neutralizing antibodies to pertussis toxin, or lymphocytosis promoting factor, was determined in six pertussis immune globulin preparations from different manufactures. A comparison with antitoxin levels after natural pertussis disease in adults showed that pertussis immune globulins did not contain more antitoxin than convalescent phase sera, i.e. they had very low antitoxin content for specific immune globulins. Agglutinin and anti-FHA titres were relatively higher in immune globulins, probably reflecting a difference between the antibody response elicited by whole cell vaccines used for hyperimmunization in immune globulin production and by natural disease. The low antitoxin content of currently available pertussis immune globulin preparations could explain the inefficacy or conflicting results obtained with these products in prophylaxis and therapy of whooping cough.  相似文献   

5.
The use of the principle of inhibition of toxin binding to an antitoxin coated immunoassay plate as described in a previous paper for tetanus antitoxin titration, was adapted for the estimation of diphtheria antitoxin in human sera. With a few modifications, a Toxin-Binding Inhibition (ToBI) test was developed which could be used for a combined estimation of both tetanus and diphtheria antitoxin levels. The application of streptavidin-biotinylated peroxidase complex when using small serum samples (less than 50 microliters) is discussed. Antitoxin titres (both diphtheria and tetanus) of 0.002 IU ml-1 were detectable by the ToBI test, this being far below the level considered to be protective in man. Sera from 140 adults with different vaccination histories were titrated for both tetanus and diphtheria antitoxin. Good correlations were found between the estimates obtained by the ToBI test and those obtained by the toxin-neutralization (TN) test in mice (tetanus antitoxin) and those obtained in the in vitro neutralization test in VERO cells (diphtheria antitoxin). It is concluded that the ToBI test is a simple and reliable alternative to the functional models currently in use for the estimation of diphtheria and tetanus antitoxin levels. In addition, the ToBI test eliminates the need for laboratory-animal or cell-culture facilities and can be performed with small quantities of serum as required in field trials.  相似文献   

6.
An enzyme-linked immunosorbent assay (ELISA) has been developed for the measurement of tetanus antitoxin in human sera as an alternative to the toxin neutralization test in mice, the currently accepted method of assay. The ELISA was found to be simple and quick to perform and required only small amounts of materials. In addition, the assay was found to give reproducible estimates of antitoxin levels and to measure antitoxin at levels as low as 0.01 IU per ml, a sensitivity similar to that of the neutralization test. Furthermore, a comparison of the results of the ELISA and the neutralization test involving 80 human sera, including sera with both high and low antitoxin levels, showed close agreement in antitoxin levels obtained by the two methods. It was concluded that ELISA was an acceptable alternative to the toxin neutralization test in mice for the measurement of tetanus antitoxin levels in human sera.  相似文献   

7.
Prophylactic tetanus antitoxin is ineffective in the prevention of experimental tetanus. That this may be true clinically is indicated by the fact that there are increasing numbers of cases of tetanus in humans after prophylactic tetanus antitoxin. Despite this known ineffectiveness and the high rate of reaction to antitoxin (5 per cent), many physicians continue to use it prophylactically, apparently for medical legal reasons. Since tetanus in civilian wounds is so rare, occurring approximately once in every million wounds, the routine use of tetanus antitoxin will probably cause more harm than good.It has been demonstrated experimentally that oxytetracycline is the most effective antimicrobial in the prevention of tetanus. It is, therefore, believed that adequate tetanus prophylaxis may be obtained by meticulous debridement and cleansing of the wound, by the administration of 1 gm. oxytetracycline daily for five days, and by intradermal administration of tetanus toxoid on the first, fourth and seventh days. Tetanus antitoxin is not given unless contaminated wounds have ben neglected for eight hours or more. In these instances, 15,000 units or more of tetanus antitoxin is given.Tetanus toxoid remains the best wound prophylaxis and greater emphasis should be placed on immunizing entire populations.  相似文献   

8.
9.
Immunochemically pure tetanus antitoxin obtained from enzyme-treated horse serum is less reactogenic and anaphylactogenic and possesses higher therapeutic properties than antitoxin purified by nonspecific physico-chemical methods and containing ballast antigens. Due to its increased persistence in the recipient's body, the immunochemically pure antitoxin induces passive immunity in considerably lower doses than the preparations purified by the method "Diaferm-3".  相似文献   

10.
目的:通过对不同厂家破伤风抗毒素产品的渗透压浓度的调查,了解国内该产品的渗透压浓度的波动范围,为生产过程中渗透压浓度质量控制提供依据。方法采用Advanced 3250型冰点渗透压仪检测破伤风抗毒素的渗透压浓度。结果不同厂家破伤风抗毒素制品的渗透压浓度均不低于240 mOsmol/L。结论破伤风抗毒素渗透压浓度波动范围均与国外同类制品基本一致,符合欧洲药典规定。  相似文献   

11.
12.
Grover SS  Negi SS  Singh S  Ray K 《Biologicals》2012,40(4):262-265
The level of circulating tetanus toxin, antitoxin and their individual influence on the outcome of tetanus cases were determined in unimmunized 125 neonatal and 39 infant cases of tetanus. PHA (passive haemagglutination) test showed 40% positive cases for toxin while its absence in the remaining cases indicated of either toxin fixation to the central nervous system (CNS) or it got neutralized by antitoxin. TN (toxin neutralization) and PHA test carried out in 46 sera samples revealed a strong positive correlation (r = 0.9) showing that 35/46 (76%) and 38/46 (82.6%) samples were positive for antitoxin, respectively. 25.4% of the neonate and infant cases and 34% of the control group had a protective serum tetanus antitoxin level. 42.5% of the paired sera from unimmunized mothers and their neonates showing nonprotective antitoxin levels suggested that a high level of antitoxin is needed for transplacental transfer, although transfer may not play a decisive role in the resistance against the disease. The presence of toxin or antitoxin in the clinical cases did not affect the outcome of the disease, although in neonates, presence of toxin was found to be a bad prognostic sign. This study explicitly advocates for the need to improve the vaccination coverage strategy.  相似文献   

13.
The tetanus antitoxin titres of 174 serum samples from healthy adults were determined by a standardization indirect haemagglutination test (IHA) and the conventional toxin neutralization (TN) test. The serum samples were titrated by the IHA test using glutaraldehyde-fixed and toxoid sensitized sheep erythrocytes before and after the treatment of the sera with 2-mercaptoethanol (2-ME). The IHA method has been found to be very sensitive and specific for the estimation of tetanus antitoxin in human sera. The IHA titres before the treatment of the sera with 2-ME were generally about four times higher than the TN titres and the correlation coefficient between these titres was 0.94. The IHA titres after the treatment of the sera with 2-ME were in good agreement with the TN titres and there was no statistically significant differences between the titres by the two methods. The tetanus antitoxin titres of 50% of the sera were below the minimum protective titres of tetanus antitoxin (0.01 IU/ml). In 19.5% of the sera the antitoxin level (IU/ml) ranged from 0.01 to 0.1, in 20.1% from 0.1 to 1.0 and in 10.4% from 1.0 to 10.0.  相似文献   

14.
L Yuan  W Lau  J Thipphawong  M Kasenda  F Xie  J Bevilacqua 《CMAJ》1997,156(7):985-990
OBJECTIVE: To determine the diphtheria and tetanus antitoxin levels among blood donors in Toronto. DESIGN: Cross-sectional seroprevalence study. SETTING: Two fixed-site blood-donation clinics in Toronto from September to November 1994. PARTICIPANTS: Blood donors 20 years of age or older were eligible to participate; of the 781 eligible donors, 710 (90.9%) participated in the study. MAIN OUTCOME MEASURES: Diphtheria and tetanus antitoxin levels and factors associated with disease susceptibility, such as vaccination history, country of birth, age and sex. A diphtheria antitoxin level lower than 0.01 lU/mL and a tetanus antitoxin level lower than 0.15 lU/mL were considered nonprotective. RESULTS: Among the participants, 147 (20.7%) had a diphtheria antitoxin level in the nonprotective range, and 124 (17.5%) had a tetanus antitoxin level that was nonprotective. Increasing age and lack of written vaccination records were associated with susceptibility to the 2 diseases. Birth outside Canada was significantly related to tetanus susceptibility. CONCLUSION: Adults over 50 years of age who did not know their vaccination history were the least likely to be protected against diphtheria and tetanus. The greatest benefit of any immunization strategy would be gained by targeting this group.  相似文献   

15.
绿脓杆菌抗毒素精制方法与效价测定方法的研究   总被引:1,自引:0,他引:1  
本文采用胃酶消化──硫酸铵盐析法对绿脓杆菌外毒素A(PEA)免疫马血浆进行了试制提纯,对该法酶处理及热变性中影响精制效果的几个主要因素进行了比较试验,同时对文中采用的4种效价测定方法进行了筛选。结果表明,胃酶消化法可用于PEA免疫马血浆的精制;效价测定以生物学方法(细胞毒性中和试验、小鼠致死毒性中和试验)为佳。综合比较试验的结果,本文拟订了PEA免疫马血浆精制的“修订法”并与“常规法”进行了精制比较。初步结果表明,修订法的精制效果优于常规法。  相似文献   

16.
Concern about the malicious applications of botulinum neurotoxin has highlighted the need for a new generation of safe and highly potent antitoxins. In this study, we developed and evaluated the preclinical pharmacology and safety of a new F(ab′)2 antitoxin against botulinum neurotoxin serotype A (BoNT/A). As an alternative to formalin-inactivated toxoid, the recombinant Hc domain of botulinum neurotoxin serotype A (rAHc) was used to immunize horses, and the IgGs from the hyperimmune sera were digested to obtain F(ab′)2 antitoxin. The protective effect of the new F(ab′)2 antitoxin against BoNT/A was determined both in vitro and in vivo. The results showed that the F(ab′)2 antitoxin could prevent botulism in mice challenged with BoNT/A and effectively delayed progression of paralysis from botulism in the therapeutic setting. The preclinical safety of the new F(ab′)2 antitoxin was also evaluated, and it showed neither harmful effects on vital functions nor adverse effects such as acute toxicity, or immunological reactions in mice and dogs. Thus, our results provide valuable experimental data for this new antitoxin as a potential candidate for treatment of botulism caused by BoNT/A, and our findings support the safety of the new F(ab′)2 antitoxin for clinical use. Our study further demonstrates the proof of concept for development of a similar strategy for obtaining potent antitoxin against other BoNT serotypes.  相似文献   

17.
The pneumococcal epsilon zeta antitoxin toxin (PezAT) system is a chromosomally encoded, class II toxin antitoxin system from the human pathogen Streptococcus pneumnoniae. Neutralization of the bacteriotoxic protein PezT is carried out by complex formation with its cognate antitoxin PezA. Here we study the stability of the inhibitory complex in vivo and in vitro. We found that toxin release is impeded in Escherichia coli and Bacillus subtilis due to the proteolytic resistance of PezA once bound to PezT. These findings are supported by in vitro experiments demonstrating a strong thermodynamic stabilization of both proteins upon binding. A detailed kinetic analysis of PezAT assembly revealed that these particular features of PezAT are based on a strong, electrostatically guided binding mechanism leading to a stable toxin antitoxin complex with femtomolar affinity. Our data show that PezAT complex formation is distinct to all other conventional toxin antitoxin modules and a controlled mode of toxin release is required for activation.  相似文献   

18.
Activities of common adjuvants were compared in mice, rabbits and monkeys with tetanus toxoid as an antigen. Aluminium gel showed consistently high adjuvanticity for antitoxin production in all animal species examined when administered subcutaneously. Water-in-oil in water (w/o/w) showed high activity comparable to that of aluminium in mice and rabbits but no activity in monkeys. Endotoxin was considerably effective in rabbits and monkeys but not so in mice. Production of both IgM and IgG antitoxin was promoted by the effective adjuvants in rabbits and monkeys. In mice, however, the effects of adjuvants on the production of IgM antitoxin was less significant and inconsistent. Contrary to the case of guinea pigs, tetanus antitoxin was produced in mice by ip injection to a level comparable to that induced by sc injection. The effects of adjuvants in mice administered by ip and sc injection were not significantly different from each other.  相似文献   

19.
20.
ELISA for the routine determination of antitoxic immunity to tetanus   总被引:4,自引:0,他引:4  
Serum samples from 727 persons with different vaccination histories were assessed for tetanus antitoxin content in an enzyme linked immunosorbent assay (ELISA) and tested for tetanus toxin neutralization activity in mice in order to compare the results obtained by the two methods. Neutralizing antibody activities in sera from individuals previously completely vaccinated correlated well with results obtained by ELISA and the accuracy increased with increasing antitoxin concentration in serum. This correlation was observed in sera from persons vaccinated recently as well as in sera from persons vaccinated many years ago. In sera from persons with an incomplete vaccination history ELISA was found to be an unreliable tool for the prediction of in vivo results. Many of these sera had antitoxin levels by ELISA far above the in vivo values, probably due to the presence of non specific or low avidity antitoxin which is detected in ELISA. The lowest ELISA value reliably predictive of protective antibody activity in serum irrespective of vaccination history was found to be 0.16 IU/ml. It was concluded that ELISA is useful for larger population studies as an initial test, but sera with an antitoxin content below 0.16 IU/ml should also be assessed in a neutralization system.  相似文献   

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