Orientador: Antonio Fernando Pestana de Castro, Nando K. Chatterjee / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-07-22T03:33:53Z (GMT). No. of bitstreams: 1 Said_AparecidaCellideAlmeida_D.pdf: 3937580 bytes, checksum: 1feafe1349dfd970ab48b2c5fcf4d58f (MD5) Previous issue date: 1997 / Resumo: A similaridade entre a proteína P2-C do vírus Coxsackie B4 e GAD humano e o possível papel dessa homologia de epótopos no desenvolvimento de uma resposta imune específica na diabetes mellitus dependente de insulina (DMDI) foi investigada. Foram produzidos anticorpos contra os peptídios sintéticos P2-C, GAD6s e GAD67 e sua imunoreatividade ftente a GAD total purificado de cérebro e pâncreas de camundongos foi analisada através do ELISA e Immunoblotting. Além disso, anticorpos anti-P2-C e anti-GAD foram pesquisados de camundongos infectados com vírus Coxsackie B4 e nos soros de pacientes com diabetes mellitus dependente de insulina. Os antissoros anti-peptídios (anti-P2-C , anti-GAD6s e anti-GAD67) reagIram fortemente com os respectivos peptídios homólogos; o antissoro anti-P2-C reagiu cruzadamente com GAD6s tão eficientemente quanto anti-GAD6s com P2-C, porém não foi detectada reação cruzada entre P2-C e GAD67, embora a reação entre os dois GADs tenha sido bastante intensa. O antissoro P2-C formou imunocomplexo com GAD6s purificado de cérebro e pâncreas de camundongo, enquanto que anti-GAD6s e anti-GAD67 também mostraram capacidade de formar imunocomplexos com GAD dessas duas fontes. A maioria dos soros de camundongos infectados foram reativos a GAD purificado de cérebro e pâncreas de camundongo e ao peptídio P2-C, enquanto que somente alguns soros reagiram ao peptídio GAD65 e muito poucos ao peptídio GAD67. Muitos soros diabéticos reagiram com GAD65 purificado e também com os peptídios P2-C e GAD65 mas somente muito poucos reagiram com o peptídio GAD67. A imunoreatividade dos soros de camundongos e dos soros humanos foi bloqueada por absorção com GAD purificado de cérebro de camundongo. Os resultados sugerem que o mimetismo molecular deve ter um papel na patogênese da Diabetes mellitus dependente de insulina (DMDI) / Abstract: The possible role of amino acid sequence and epitope homologies between a protein P2-C of Coxsackie virus B4 and human GAD in the development of host-specific immune response in insulin-dependent diabetes mellitus (100M) (molecular mimicry) was investigated. Peptide antibodies to the P2-C protein, GAD65 and GAD67 were raised to analyze their immunoreactivity by enzyme-linked immunosorbent assay and immunoblotting with GAD purified from the brain and pancreas of mice that develop hyperglycemia after the infection. Additionally, antibody reactivity to these peptide antigens was assessed in sera from the virus-infected mice and IDDM patients. All three peptide antisera reacted very strongly with homologous peptides; P2-C antiserum cross-reacted with GAD6s as efficiently as GAD65 antiserum with P2-C, but no cross-reaction was detected between P2-C and GAD67 although cross-reaction between the two GADs was quite pronounced. P2-C antiserum immunocomplexed with GAD65 from mouse brain or pancreas, whereas GAD65 and GAD67 antisera both immunocomplexed with the two GADs from these sources. Most of the sera from virus-infected mice were reactive to brain and pancreas GAD65 and also to P2-C peptide, whereas some reacted to GAD65 and a few to GAD67 peptides. A number of rnOM sera reacted with mouse GAD65 and also with P2-C and GAD65 peptides, whereas only a few reacted with GAD67 peptide. The immunoreactivity of the mouse and IDDM sera to P2-C and GAD65 peptides was blocked by pre-adsorption with mouse GAD. The results suggest that molecular mimicry may play a role in the pathogenesis of the disease / Doutorado / Doutor em Ciências