O papel das imunidades nas relações parasito-hospedeiro: o carrapato Rhipicephalus (Boophilus ) microplus e bovinos resistentes ou susceptíveis
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Data
2006-06-21
Autores
Carvalho, Wanessa Araújo [UNESP]
Título da Revista
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
No hospedeiro bovino o nível de resistência ao carrapato Rhipicephalus (Boophilus) microplus varia de acordo com a raça sendo os fenótipos contrastantes herdáveis. O presente trabalho explora esses fenótipos a fim de estabelecer os perfis das respostas imunes, humoral e inflamatória, correlacionados com resistência em raça zebuína (Nelore) e susceptibilidade em raça taurina (HPB). Os animais foram expostos a infestação natural pelo R.(B.) microplus e amostras de soros foram coletadas em pontos estratégicos da cinética das infestações. Os níveis de imunoglobulinas totais (IgG1 e IgG2), bem como os de anticorpos IgG1, IgG2 e IgE anti-extrato de ovo, anti-extrato de larva não alimentada e anti-saliva foram determinados. Elementos da resposta inflamatória, como as principais proteínas de fase aguda e óxido nítrico, também foram dosados. Os resultados obtidos mostram que as infestações muito intensas, em hospedeiros suscetíveis, são capazes de modular os níveis séricos de IgG1 e IgG2 total, diminuindo-os significativamente em relação aos níveis observados durantes infestações menores. Também modulam negativamente a produção de todos os anticorpos específicos IgG1 e IgG2 avaliados a nível sistêmico. Bovinos susceptíveis ao carrapato produzem níveis mais altos de anticorpos IgE para todos os antígenos. O fenótipo susceptivel de infestação se diferencia pela maior freqüência do alótipo de IgG?2a, herdado por herança Mendeliana co-dominante. Animais suscetíveis, quando infestados, produzem níveis mais altos da proteína de fase aguda a1- glicoproteína ácida, de padrão anti-inflamatório, enquanto que animais resistentes produziram relativamente mais proteínas de fase aguda pró-inflamatórias, haptoglobina e amilóide sérica A. Em ambas as raças não houve diferença nos níveis de transferrina e óxido nítrico sistêmico, porém a produção de ambos é influenciada pelos níveis de infestação.
In bovine hosts resistance to the cattle tick, Rhipicephalus (Boophilus) microplus, varies according to the breed, being the phenotypes of infestations inherited. The present work exploits these contrasting phenotypes in order to determine the profile of the humoral, inflammatory and acute phase responses that are correlated with resistance seen in a zebuine breed (Nelore) and susceptibility seen in a taurine breed (Holstein). Bovines were exposed to natural infestations with R.(B.) microplus and they presented, as expected, different levels of infestation that also varied in intensity according to the season of the year. Samples of sera were collected at strategic points during the kinetics of different cycles of infestations. The levels of total serum IgG1 and IgG2 immunoglobulins, as well as those of IgG1, IgG2 and IgE anti-egg extracts, anti-unfed larvae extracts and anti-saliva antibodies were measured. Components of the inflammatory response, nitric oxide, as well as acute phase proteins, were also measured. The results show that very intense infestations in ticksusceptible bovines modulate the serum levels of IgG1 and IgG2, which are significantly diminished relative to those observed during less intense infestations. Intense infestations also modulate the production of all specific IgG1 and IgG2 antibodies. Susceptible animals produced more specific IgE, suggesting that this isotype does not participate in resistance against ticks. The susceptible cattle also have a higher frequency of IgG?2a , which are encoded by Mendelian co-dominant alleles. When infested susceptible animals produced higher levels of the anti-inflammatory acute phase protein, a1-acid glycoprotein, whereas resistant animals produced relatively higher levels of the pro-inflammatory proteins, haptoglobin and serum amyloide A.
In bovine hosts resistance to the cattle tick, Rhipicephalus (Boophilus) microplus, varies according to the breed, being the phenotypes of infestations inherited. The present work exploits these contrasting phenotypes in order to determine the profile of the humoral, inflammatory and acute phase responses that are correlated with resistance seen in a zebuine breed (Nelore) and susceptibility seen in a taurine breed (Holstein). Bovines were exposed to natural infestations with R.(B.) microplus and they presented, as expected, different levels of infestation that also varied in intensity according to the season of the year. Samples of sera were collected at strategic points during the kinetics of different cycles of infestations. The levels of total serum IgG1 and IgG2 immunoglobulins, as well as those of IgG1, IgG2 and IgE anti-egg extracts, anti-unfed larvae extracts and anti-saliva antibodies were measured. Components of the inflammatory response, nitric oxide, as well as acute phase proteins, were also measured. The results show that very intense infestations in ticksusceptible bovines modulate the serum levels of IgG1 and IgG2, which are significantly diminished relative to those observed during less intense infestations. Intense infestations also modulate the production of all specific IgG1 and IgG2 antibodies. Susceptible animals produced more specific IgE, suggesting that this isotype does not participate in resistance against ticks. The susceptible cattle also have a higher frequency of IgG?2a , which are encoded by Mendelian co-dominant alleles. When infested susceptible animals produced higher levels of the anti-inflammatory acute phase protein, a1-acid glycoprotein, whereas resistant animals produced relatively higher levels of the pro-inflammatory proteins, haptoglobin and serum amyloide A.
Descrição
Palavras-chave
Humoral immune response, Acute phase proteins, Nitric oxide, Bovino, Relação hospedeiro-parasito, Rhipicephalus, Resposta imune, Óxido nítrico
Como citar
CARVALHO, Wanessa Araújo. O papel das imunidades nas relações parasito-hospedeiro: o carrapato Rhipicephalus (Boophilus ) microplus e bovinos resistentes ou susceptíveis. 2006. xii, 113 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Ciências Agrárias e Veterinárias, 2006.