RESUMO
Symmetric and asymmetric IgGs having different neutralizing capacity are synthesized in variable proportions by the same clones during the course of immune response. The neutralizing activity of tetanus antibodies was studied in rabbits vaccinated with acellular (DTPa) or whole-cell pertussis (DTPw) vaccines. Symmetric and asymmetric F(ab)'2 fragments from the IgG fraction of the peak serum pools from each group of rabbits were purified by concanavalin A chromatography and measured by ELISA. After the third vaccine dose the asymmetric antibody percentage for DTPw (40%) was twice that for DTPa (20%). The neutralizing activity of asymmetric antibodies was roughly sixfold lower than symmetric ones. When antibody values titrated by ELISA approach minimal protective level, the proportion of symmetric antibodies with high toxin neutralizing activity acquires crucial importance.
Assuntos
Anticorpos Antibacterianos/biossíntese , Vacina contra Difteria, Tétano e Coqueluche/farmacologia , Tétano/imunologia , Animais , Anticorpos Antibacterianos/sangue , Anticorpos Antibacterianos/imunologia , Antígenos de Bactérias/sangue , Antígenos de Bactérias/imunologia , Bordetella pertussis/imunologia , Vacina contra Difteria, Tétano e Coqueluche/imunologia , Ensaio de Imunoadsorção Enzimática , Fragmentos de Imunoglobulinas/sangue , Imunoglobulina G/biossíntese , Imunoglobulina G/sangue , Testes de Neutralização , Coelhos , Relação Estrutura-Atividade , Toxoide Tetânico/imunologiaRESUMO
PROBLEM: The structure and protective activity of antibodies against tetanus (anti-T) and diphtheria (anti-D), produced during human pregnancy and transferred to new-born, was studied. METHOD: Antibody levels were measured by ELISA in non-pregnant women (control group), primiparae, and multiparae, and in their children. The proportion of symmetric and asymmetric IgG molecules was determined and their respective protective capacity evaluated. RESULTS: The quantity of asymmetric anti-T and anti-D antibodies in mothers at the time of delivery was roughly four- and three-fold that of the control group, respectively, dropping significantly 1 month later. A similar proportion of these antibodies was observed in the new-born. The lower neutralizing capacity of asymmetric molecules was demonstrated in vivo. CONCLUSION: Results show that during pregnancy there is a modulation of the immune response with an increase in the production of asymmetric molecules of lower protective capacity.
Assuntos
Anticorpos Antibacterianos/biossíntese , Anticorpos Antibacterianos/química , Difteria/prevenção & controle , Imunidade Materno-Adquirida/imunologia , Recém-Nascido/imunologia , Tétano/prevenção & controle , Adolescente , Adulto , Animais , Anticorpos Antibacterianos/uso terapêutico , Difteria/imunologia , Vacina contra Difteria, Tétano e Coqueluche/imunologia , Feminino , Cobaias , Humanos , Fragmentos Fab das Imunoglobulinas/biossíntese , Fragmentos Fab das Imunoglobulinas/química , Fragmentos Fab das Imunoglobulinas/uso terapêutico , Imunoglobulina G/biossíntese , Imunoglobulina G/química , Imunoglobulina G/uso terapêutico , Camundongos , Gravidez , Relação Estrutura-Atividade , Tétano/imunologia , Toxoide Tetânico/imunologiaRESUMO
The immunogenicity of the diphtheria component of 73 commercial vaccines from five different manufacturers was tested by the toxin neutralization test (TNT) and the enzyme-linked immunosorbent assay (ELISA) developed in our laboratory. A comparison of the antibody levels measured by both assays showed a very good correlation (r = 0.95, p < 0.001). The results suggest that the proposed ELISA is a reliable, simple and economical alternative to the TNT in guinea pigs. Also, the ELISA was found to measure IgG antibody levels as low as 5.5 x 10(-5) IU ml-1. To evaluate the possibility of accelerating the active immunization during the activity test of vaccines, an alternative schedule using one single human dose was assayed. A very good correlation was observed between the IgG antibody response obtained with this schedule and with the traditional programme. Therefore, the cost and the time required to perform the activity test may be considerably reduced when both the rapid immunization schedule and the ELISA are used.
Assuntos
Anticorpos Antibacterianos/sangue , Toxoide Diftérico/imunologia , Animais , Toxoide Diftérico/farmacologia , Ensaio de Imunoadsorção Enzimática , Feminino , Cobaias , Esquemas de Imunização , Imunoglobulina G/sangue , Masculino , Testes de Neutralização , Reprodutibilidade dos TestesRESUMO
An inhibition enzyme-linked immunosorbent assay was developed for Pseudomonas fluorescens enumeration of meat surfaces. The assay detected contamination levels as low as 3 x 10(5) bacteria per ml and could be completed within 4 h. It could be used as a framework for a test system for quantifying P. fluorescens spoilage in meat products.
Assuntos
Ensaio de Imunoadsorção Enzimática/métodos , Carne/microbiologia , Pseudomonas fluorescens/isolamento & purificação , Microbiologia de AlimentosRESUMO
An enzyme-linked immunosorbent assay (ELISA) has been developed to measure anti-tetanus toxoid antibody levels in immunized guinea-pig sera as a useful alternative to the currently used toxin neutralization test (TNT) in determining the activity of the tetanus toxoid in vaccines. The ELISA was found to measure antibody levels as low as 5.8 x 10(-5) IU/ml. Furthermore, a comparison of the results from ELISA and TNT involving 132 different commercial vaccines showed a very good correlation (r = 0.94, p < 0.001) between antibody levels measured by both methods. The results suggest that the proposed ELISA is a reliable, simple and economical alternative to the TNT in mice for assessing the activity of tetanus toxoids in vaccines.
Assuntos
Anticorpos Antibacterianos/análise , Ensaio de Imunoadsorção Enzimática/métodos , Testes de Neutralização/métodos , Toxoide Tetânico/análise , Animais , Feminino , Cobaias , Masculino , Camundongos , Toxoide Tetânico/imunologiaRESUMO
N:NIH mice were vaccinated according to the WHO recommendations for the potency test with the Second International Standard for Pertussis Vaccine (ISPV). Blood for serological investigation was taken from the animals on day 14 post immunization before intracerebral challenge with Bordetella pertussis 18323 was done. The relationship between anti-pertussis toxin, anti-filamentous hemagglutinin and anti-adenylate cyclase antibody levels as measured by ELISA and protection from intracerebral challenge was studied. The proportion of surviving mice increased in correlation with increasing anti-PT titres; a protective level of 4 ELISA units/ml was found. Such relationship between protection against intracerebral challenge and antibody titres was not found for anti-FHA nor for anti-AC antibodies, thus suggesting that these antibodies do not play an important role in protection in this model. The excellent correlation between anti-PT antibody titres and protection suggests that the measure of anti-PT response could be a useful tool for estimating the potency of whole-cell vaccines. The development of an alternative method for testing the potency of pertussis whole-cell vaccines based on the anti-PT response should be considered.
Assuntos
Adenilil Ciclases/imunologia , Anticorpos Antibacterianos/biossíntese , Encefalopatias/prevenção & controle , Hemaglutininas/imunologia , Vacina contra Coqueluche/imunologia , Coqueluche/prevenção & controle , Toxina Adenilato Ciclase , Animais , Antígenos de Bactérias/imunologia , Encefalopatias/imunologia , Encefalopatias/microbiologia , Feminino , Masculino , Camundongos , Toxina Pertussis , Vacina contra Coqueluche/normas , Fatores de Virulência de Bordetella/imunologia , Coqueluche/mortalidade , Coqueluche/veterináriaRESUMO
The antibody response to filamentous haemagglutinin and pertussis toxin was studied in N:NIH mice vaccinated according to the WHO recommendations for potency test with the International Standard for Pertussis Vaccine (ISPV). Some of the vaccinated animals were challenged intracerebrally on day 14. All animals, whether challenged or not, were bled on days 7, 14, 21, 28 and 35 after immunization. The relationship between anti-PT and anti-FHA antibodies measured by ELISA and protection from intracerebral challenge was examined. All those mice with anti-PT titres on day 14 higher than 43 EU/ml survived challenge. No relationship was found between anti-FHA antibodies and survival. Anti-PT titres on day 14 below 43 EU/ml were related to the days of survival after challenge; a linear regression curve of y = 13 + 2.4x, with a correlation coefficient r = 0.61 was found. Anti-PT antibodies seem to play an important role in protection when animals are challenged intracerebrally, as is the case in the standard potency test for pertussis vaccine.