RESUMO
For serologically characterizing a recent primary toxoplasma infection, the low avidity of IgG specific antibodies was studied. Avidity was evaluated as the decrease of IgG antibody titers in ELISA after treating plates with 6 M urea, as a dissociating solution of low avidity antigen-antibody complexes. Sixty nine serum samples were studied, presenting characteristic patterns of recent, transitional or chronic toxoplasmosis. Serological patterns were determined according to results of IgG and IgM immunofluorescence, IgM-capture, and hemagglutination tests. Twenty three serum samples from each of the referred patterns I, II and III were titrated. For chronic toxoplasmosis infections, which presented a serological pattern III, observed decrease of titers was 3% +/- 3%. For pattern I recent toxoplasmosis sera it was 34% +/- 12%, and for transition pattern II, 12% +/- 9%. Thus, a low avidity of IgG specific antibodies can be applicable for the diagnosis of a recent toxoplasmosis infection.
Assuntos
Anticorpos Antiprotozoários/sangue , Afinidade de Anticorpos/imunologia , Imunoglobulina G/sangue , Toxoplasmose/imunologia , Animais , Biomarcadores , Ensaio de Imunoadsorção Enzimática , Imunofluorescência , Humanos , Imunoglobulina M/sangue , Toxoplasma/imunologiaRESUMO
A significantly diminished antibody response to hepatitis B vaccine has been demonstrated in adults when the buttock is used as the injection site. However, in Brazil, the buttock continues to be recommended as site of injection for intramuscular administration of vaccines in infants. In this age group, there are no controlled studies evaluating the immunogenicity of the hepatitis B vaccine when administered at this site. In the present study, 258 infants were randomized to receive the hepatitis B vaccine either in the buttock (n = 123) or in the anterolateral thigh muscle (n = 135). The immunization schedule consisted of three doses of hepatitis B vaccine (Engerix Bregister mark or target, 10 microg) at 2, 4 and 9 months of age. There were no significant differences in the proportion of seroconversion (99.3% x 99.2%), or in the geometric mean titer of ELISA anti-HBs (1,862.1 x 1,229.0 mIU/mL) between the two groups. This study demonstrates that a satisfactory serological response can be obtained when the hepatitis B vaccine is administered intramuscularly into the buttock.
Assuntos
Vacinas contra Hepatite B/administração & dosagem , Esquemas de Imunização , Injeções Intramusculares/métodos , Nádegas , Humanos , Lactente , Coxa da PernaRESUMO
The periods of persisting immunoglobulin M class antibodies to hepatitis B core antigen in 28 patients with acute hepatitis B infections and in 134 patients with chronic hepatitis B infections were studied by using an enzyme-linked immunosorbent assay and an indirect immunofluorescence technique. We showed that the clearance of antibodies to hepatitis B core antigen is independent of the degree of viremia in both forms of hepatitis.
Assuntos
Anticorpos Anti-Hepatite B/metabolismo , Antígenos do Núcleo do Vírus da Hepatite B/imunologia , Hepatite B/imunologia , Doença Crônica , Ensaio de Imunoadsorção Enzimática , Imunofluorescência , Hepatite B/microbiologia , Humanos , Imunoglobulina M/metabolismo , Taxa de Depuração Metabólica , Fatores de TempoRESUMO
This study was undertaken to evaluate an enzyme immunoassay (EIA) for hepatitis C virus antibody detection (anti-HCV), using just one antigen. Anti-HCV EIA was designed to detect anti-HCV IgG using on the solid-phase a recombinant C22 antigen localized at the N-terminal end of the core region of HCV genome, produced by BioMérieux. The serum samples diluted in phosphate buffer saline were added to wells coated with the C22, and incubated. After washings, the wells were loaded with conjugated anti-IgG, and read in a microtiter plate reader (492 nm). Serum samples of 145 patients were divided in two groups: a control group of 39 patients with non-C hepatitis (10 acute hepatitis A, 10 acute hepatitis B, 9 chronic hepatitis B, and 10 autoimmune hepatitis) and a study group consisting of 106 patients with chronic HCV hepatitis. In the study group all patients had anti-HCV detected by a commercially available EIA (Abbott), specific for HCV structural and nonstructural polypeptides, alanine aminotransferase elevation or positive serum HCV-RNA detected by nested-PCR. They also had a liver biopsy compatible with chronic hepatitis. The test was positive in 101 of the 106 (95%) sera from patients in the study group and negative in 38 of the 39 (97%) sera from those in the control group, showing an accuracy of 96%. According to these results, our EIA could be used to detect anti-HCV in the serum of patients infected with hepatitis C virus.
Assuntos
Hepacivirus/imunologia , Anticorpos Anti-Hepatite C/isolamento & purificação , Técnicas Imunoenzimáticas/métodos , Proteínas Recombinantes , Proteínas do Core Viral/imunologia , Adolescente , Adulto , Idoso , Alanina Transaminase/sangue , Ensaio de Imunoadsorção Enzimática , Feminino , Hepacivirus/genética , Anticorpos Anti-Hepatite C/sangue , Hepatite C Crônica/diagnóstico , Humanos , Imunoglobulina G/isolamento & purificação , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , RNA/sangueRESUMO
A caracterizacao de infeccao primaria recente pelo Toxoplasma gondii se apoia principalmente na presenca, no soro, de anticorpos especificos IgM. Para fins diagnosticos de toxoplasmose aguda, ou de contagio recente, a possibilidade de outros marcadores e altamente desejavel. Um marcador de infeccao recente atualmente referido e a baixa afinidade ou avidez de anticorpos especificos IgG. Para avaliacao do novo marcador, titularam-se os soros contra poliantigenos do T.gondii pelo teste imunoenzimatico (ELISA), antes e apos tratamento dos complexos antigeno-anticorpo formados, com solucao de ureia 6 M como agente dissociante. O deslocamento de anticorpos de baixa avidez foi indicado por uma queda de titulos, calculada em porcentagem em relacao aos titulos iniciais. Foram estudados 69 soros, 23 de cada um dos 3 perfis sorologicos sucessivos, observados na infeccao, e que a caracterizam respectivamente como recente, em fase de transicao e cronica. Os perfis foram determinados segundo os resultados de uma bateria de testes, incluindo os de imunofluorescencia IgG e IgM, de captura de anticorpos IgM e de hemaglutinacao. Para os soros de infeccao cronica a queda observada foi de 3 por cento ñ 3 por cento, de 34 por cento ñ 12 por cento para toxoplasmose recente e de 12 por cento ñ 9 por cento para a fase de transicao...
Assuntos
Animais , Humanos , Anticorpos Antiprotozoários/sangue , Afinidade de Anticorpos/imunologia , Imunoglobulina G/sangue , Toxoplasmose/imunologia , Biomarcadores , Ensaio de Imunoadsorção Enzimática , Imunofluorescência , Imunoglobulina M/sangue , Toxoplasma/imunologiaRESUMO
This study was undertaken to evaluate an enzyme immunoassay (EIA) for hepatitis C virus antibody detection (anti-HCV), using just one antigen. Anti-HCV EIA was designed to detect anti-HCV IgG using on the solid-phase a recombinant C22 antigen localized at the N-terminal end of the core region of HCV genome, produced by BioMérieux. The serum samples diluted in phosphate buffer saline were added to wells coated with the C22, and incubated. After washings, the wells were loaded with conjugated anti-IgG, and read in a microtiter plate reader (492 nm). Serum samples of 145 patients were divided in two groups: a control group of 39 patients with non-C hepatitis (10 acute hepatitis A, 10 acute hepatitis B, 9 chronic hepatitis B, and 10 autoimmune hepatitis) and a study group consisting of 106 patients with chronic HCV hepatitis. In the study group all patients had anti-HCV detected by a commercially available EIA (Abbott(r)), specific for HCV structural and nonstructural polypeptides, alanine aminotransferase elevation or positive serum HCV-RNA detected by nested-PCR. They also had a liver biopsy compatible with chronic hepatitis. The test was positive in 101 of the 106 (95 percent) sera from patients in the study group and negative in 38 of the 39 (97 percent) sera from those in the control group, showing an accuracy of 96 percent. According to these results, our EIA could be used to detect anti-HCV in the serum of patients infected with hepatitis C virus.