Potential immunological markers for diagnosis and therapeutic assessment of toxocariasis / Estudo de marcadores imunológicos para o diagnóstico e avaliação terapêutica da toxocaríase

In human toxocariasis, there are few approaches using immunological markers for diagnosis and therapeutic assessment. An immunoblot (IB) assay using excretory-secretory Toxocara canis antigen was standardized for monitoring IgG, IgE and IgA antibodies in 27 children with toxocariasis (23 visceral, three mixed visceral and ocular, and one ocular form) for 22-116 months after chemotherapy. IB sensitivity was 100 percent for IgG antibodies to bands of molecular weight 29-38, 48-54, 95-116, 121-162, >205 kDa, 80.8 percent for IgE to 29-38, 48-54, 95-121, > 205 kDa, and 65.4 percent for IgA to 29-38, 48-54, 81-93 kDa. Candidates for diagnostic markers should be IgG antibodies to bands of low molecular weight (29-38 and 48-54 kDa). One group of patients presented the same antibody reactivity to all bands throughout the follow-up study; in the other group, antibodies decayed partially or completely to some or all bands, but these changes were not correlated with time after chemotherapy. Candidates for monitoring patients after chemotherapy may be IgG antibodies to > 205 kDa fractions, IgA to 29-38, 48-54, 81-93 kDa and IgE to 95-121 kDa. Further identification of antigen epitopes related to these markers will allow the development of sensitive and specific immunoassays for the diagnosis and therapeutic assessment of toxocariasis.

Métodos imunológicos desempenham papel importante no diagnóstico da toxocaríase, entretanto há poucos estudos sobre marcadores diagnósticos e de acompanhamento terapêutico. Foi padronizado ensaio de immunoblot (IB) empregando antígeno de excreção-secreção de Toxocara canis para pesquisa de anticorpos IgG, IgE e IgA em 27 crianças com toxocaríase nas formas visceral (23), mista visceral e ocular (3) e ocular (1), por 22-116 meses após quimioterapia. Foram observados dois perfis de reatividade dos anticorpos: permanência contra todas as frações no decorrer do estudo; diminuição ou negativação contra algumas ou todas as frações, porém, essas mudanças não se correlacionaram com tempo de tratamento. A sensibilidade do IB foi 100,0 por cento para anticorpos IgG específicos para frações de massa molecular de 29-38, 48-54, 95-116, 121-162, > 205 kDa, 80,8 por cento para IgE específicos para 29-38, 48-54, 95-121, > 205 kDa e 65,4 por cento para IgA específicos para 29-38, 48-54, 81-93 kDa. Anticorpos IgG específicos para frações de baixa MM (29-38 e 48-54 kDa) podem ser sugeridos como candidatos a marcadores diagnósticos. Por sua vez, anticorpos IgG para fração > 205 kDa, IgA para 29-38, 48-54, 81-93 kDa e IgE para 95-121 kDa podem ser candidatos a marcadores terapêuticos. A identificação de epítopos antigênicos relacionados a estes marcadores poderá ser importante para o desenvolvimento de ensaios altamente sensíveis e específicos no diagnóstico e avaliação terapêutica da toxocaríase.

Systemic and local antibodies induced by an experimental inactivated vaccine against bovine herpesvirus type 1 / Anticorpos locais e sistêmicos induzidos por uma vacina experimental inativada contra o herpesvírus bovino tipo 1

An experimental inactivated vaccine against bovine herpesvirus-1 (BoHV-1) was produced aiming to evaluate the systemic and local antibody responses in 12 seronegative heifers, after vaccination and revaccination. Serum samples were submitted to virus neutralization assay and to ELISA test for detection of IgG1 and IgG2 isotypes. Nasal secretion samples were submitted to the same ELISA test for detection of IgG1 and IgG2 isotypes. The results showed that moderate to high neutralizing titres and IgG1 and IgG2 antibody responses were induced after the second vaccination in the serum and in nasal secretions up to 114 days post vaccination. IgG2 antibodies were the prevalent isotype for most of the post-vaccination period. The results indicate that BoHV-1 experimental inactivated vaccine elicited potentially protective IgG1 and IgG2 antibody levels, both in the systemic and mucosal compartments.

Uma vacina experimental inativada contra o herpesvírus bovino tipo 1 (BoHV-1) foi produzida com o objetivo de se avaliar a resposta imune humoral local e sistêmica contra o BoHV-1, em 12 novilhas soronegativas, após a vacinação e a revacinação. Os soros foram submetidos à prova de vírus-neutralização para quantificação do título de anticorpos neutralizantes e a um ELISA para detecção de IgG1 e IgG2. Os swabs nasais também foram submetidos ao ELISA para detecção de IgG1 e IgG2 na secreção nasal. Os resultados demonstraram que títulos de anticorpos neutralizantes foram induzidos após a revacinação, em níveis moderados a altos, permanecendo em níveis significativos no soro sanguíneo e na secreção nasal até o dia 114 pós-vacinação. O IgG2 foi o isótipo predominante na maior parte do período pós-vacinação, tanto na secreção nasal, como no compartimento sistêmico. A vacina experimental inativada contra o BoHV-1 estimulou níveis de anticorpos potencialmente protetores dos isótipos IgG1 e IgG2, tanto no compartimento sistêmico, como nas mucosas.

Induction of Active Systemic Anaphylaxis and Immunological Aspects in Mice Sensitized with House Dust Mite / 대한면역학회지

We have used BALB/c mice as an animal model for the study of anaphylactic hypersensitivity to the house dust mite. For the sensitization, BALB/c mice were injected with a single dose of extracts of Oermatophagoides farinae (D. pa) or Dermatophagoides pteronyssinus (D. pt) mixed with adjuvants (aluminum hydroxide and Bordetella pertussis) intraperitonealy. On days of 15, 30, and 60 after the sensitization, the mice received a challenge dose of the same allergen intravenously to induce anaphylactic shock. The hypersensitivity reactions were scored by anaphylactic shock. And various immunological parameters, including cytokines and immunoglobulin isotypes, were studied in relation with the shock. A high level of anaphylactic shock was produced in the mice by both of the allergens, D, fa and D, pt, at 15 and 30 days after sensitization. In vitro Ag specific proliferative reponses of spleen cells from D. pt treated mice (D. pt mice) was six times higher than those from O. fa treated mice (O. fa mice). Regardless the differences in antigens, the production of IFN-r by spleen cells from D. pt mice or O. fa mice was equally high at 15 days after sensitization. However, the ability to produce IFN-r by the spleen cells from D, pt mice was three times higher compared to that from D. fa mice. The production of IL-4 by the spleen cells was enhanced slightly but not significant in both groups. In studies of the allergen-specific immunoglobulin isotypes in the sera of the mice, the level of IgE in both groups was enhanced slightly but not significant. In contrast, the level of IgG subtypes were increased in both groups. When the levels of IgG were compared by subtypes, the level of IgG1 increased significantly on day 15 when the anaphylactic shock score was maximized in both groups. Increase in IgG2a level at the day was not significant, instead, asignificant increase in IgG2 levels was observed on day 60 after sensitization when the anaphylaxis was almost discontinued. Although a higher level of IgG3 was examined on day 15 and 30 in D. pt mice and on day 60 in D, fa mice, anaphylaxis was not appeared to be associated with the levels of IgG3 in this study. The IgG1, rather than IgE, was assumed to the major factor involved in the anaphylactic response observed in this experiment. In conclusion, BALB/c mice would be an animal model for the study of anaphylactic hypersensitivity to D. fa or D, pt., which might be an essential tool for the future development of immuno-therapeutic agents.