Produção de anticorpos policlonais para detecção de bovicina HC5 por ensaios imunoenzimáticos

• Ano de defesa: 2007
• Autor(a) principal: Paiva, Aline Dias
• Orientador(a): Mantovani, Hilário Cuquetto
• Banca de defesa: Moraes, Célia Alencar de , Passos, Flávia Maria Lopes
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Microbiologia Agrícola
• Departamento: Associações micorrízicas; Bactérias láticas e probióticos; Biologia molecular de fungos de interesse
• País: BR
• Palavras-chave em Português: Bovicina HC5; Anticorpos; Ensaio imunoenzimático
• Palavras-chave em Inglês: Bovicin HC5; Antibodies; Immunoenzymatic assays
• Área do conhecimento CNPq: CNPQ::CIENCIAS BIOLOGICAS::MICROBIOLOGIA::BIOLOGIA E FISIOLOGIA DOS MICROORGANISMOS
• Link de acesso: http://locus.ufv.br/handle/123456789/5388

Some bacteria produce antimicrobial peptides called bacteriocins that show bactericidal or bacteriostatic effect against other bacteria from the same species or species that are phylogenetically related. These peptides have been studied mainly due to their potential application in food industry, in medicine and in livestock production. Bovicin HC5, a bacteriocin produced by Streptococcus bovis HC5, is similar to the lantibiotics and has a wide spectrum of action. Despite the great potential for practical applications, the production of bacteriocins is frequently limited by the methods used for detection, quantification and purification. However, immunoenzymatic assays can be used as an effective alternative to detect and purify antimicrobial peptides. This work aimed to produce polyclonal antibodies to detect and quantify the bacteriocin bovicin HC5 by immunoenzymatic assays and also to determine the cytotoxic effect of this bacteriocin on Vero cells. Production of the polyclonal antibodies was performed using HPLC-purified peptide followed by immunization of New Zealand rabitts and BALB/c mice. Periodical blood harvests were performed for up to 60 days. Immunoenzymatic analysis was carried out by indirect ELISA and Western blotting with samples from blood serum, S. bovis HC5 cell extracts or supernatants from cultures grown in basal media. Bovicin HC5 generated a immune response of moderated intensity. Nonspecific reactions were not observed between the antibody and the supernatants of other lactic acid cultures by Western blotting and indirect ELISA analysis. Only the purified bovicin HC5 was detected using these techniques. Agar diffusion assays indicated that the anti-bovicin HC5 anti-serum could neutralize 75 % of the bacteriocin activity. The bioassay also indicated that production of bovicin HC5 by S. bovis HC5 started during exponential phase and the biological activity of the bacteriocin increased when the culture reached stationary phase. Bovicin HC5 could be detected in the cell extract and in the supernatant of the S. bovis HC5 culture using the indirect ELISA technique. There was a direct relationship between the activity determined by the ELISA technique and the bioassays. Bovicin HC5 showed toxic effect against Vero cells at concentrations equal to or greater than 100 μg mL-1. These results indicated that immunoenzymatic assays can be used to detect bovicin HC5, but further work is needed to improve the sensitivity of the technique. The effect of bovicin HC5 on different cell lineages must also be investigated to evaluate the toxicity of the peptide and its potential application in animal production.