Proteção de bovinos contra Haemonchus placei e Haemonchus contortus após imunização com antígenos oriundos da membrana intestinal de H. contortus
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Data
2011-02-21
Autores
Bassetto, César Cristiano [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Neste estudo avaliou-se a eficácia de uma vacina constituída de glicoproteínas obtidas da membrana do intestino de Haemonchus contortus em bezerros desafiados com H. contortus ou H. placei. Bezerros holandeses machos, criados livres de infecções por helmintos, foram distribuídos em quatro grupos com nove animais cada. Dois grupos foram vacinados com 50 μg do imunógeno diluído no adjuvante QuilA, enquanto os outros dois grupos foram os controles, receberam apenas adjuvante. A vacina foi administrada três vezes com intervalo de 21 dias entre as aplicações. Os bezerros foram artificialmente infectados sete dias após a última imunização e sacrificados para contagem dos vermes 43 dias depois. Os bezerros de um dos grupos vacinados receberam 8000 larvas infectantes (L3) de H. contortus enquanto os do outro grupo foram infectados com o mesmo número de L3 de H. placei. Os controles foram infectados na mesma ocasião com o mesmo número de L3 de H. contortus ou H. placei. A vacinação reduziu significativamente a contagem de ovos por grama de fezes (OPG) e a carga parasitária (P<0,01). A titulação de anticorpos nos animais controle permaneceu perto de zero enquanto nos animais vacinados verificou-se elevada titulação de anticorpos no soro. Os bezerros vacinados e desafiados com H. contortus não eliminaram ovos nas amostras de fezes, enquanto os controles apresentaram média máxima (± erro padrão) de 61,1 (±42,3) OPG 31 dias após a infecção. A partir deste dia, a contagem de OPG diminuiu progressivamente neste grupo controle com apenas um animal eliminando ovos nas fezes 42 dias após a infecção. Nos controles de H. placei, o ápice na contagem de OPG ocorreu 35 dias após a infecção (61,1 ± 21,7) e permaneceu relativamente constante até o final do estudo, enquanto no grupo vacinado apenas dois animais eliminaram ovos nas fezes, na última coleta. Os animais controle...
This study evaluated the efficacy of a vaccine containing integral membrane glycoproteins from the intestine of Haemonchus contortus in calves challenged with H. contortus or Haemonchus placei. Males Holstein calves, raised worm free, were distributed into four groups with nine animals each. Two groups were vaccinated with 50 μg of antigen diluted on QuilA adjuvant, while the others two groups were the controls and received only adjuvant. The vaccine was administered three times 21 days apart. Either vaccinated or not and challenged with either 8,000 H. contortus or H. placei infective larvae. The calves were challenged 7 days after the last immunization and killed for worm counts 43 days later. Vaccination significantly reduced faecal egg counts (FEC) and worm burdens (P< 0.01). Antibody titres in the calves control stayed close to zero meanwhile in the calves vaccinated was observed high antibody titres in the serum. Calves vaccinated and challenged with H. contortus did not shed eggs in faecal samples, while the controls showed a maximum mean (± standard error) FEC of 61.1 (±42.3) at 31 days post infection. Then, FEC progressively declined in this group with only one animal shedding eggs in faeces 42 days post infection. With H. placei the controls FEC peaked at 35 days post infection (61.1 ±21.7) and remained relatively constant until the end of the study, while in the vaccinated group only two animals shed eggs and only on the last collection date. With H. placei the controls contained a mean of 551.1 (±93.7) parasites, while the vaccinates had 174.4 (±56.3) worms. The establishment rate of H. contortus was lower than that of H. placei (P< 0.01) with an average of 163.9 (±39.4) and 74.4 (±20.4) specimens in the control and vaccinated groups, respectively. It was concluded that vaccination of calves with antigens obtained from H. contortus conferred protection against both H. placei and H. contortus
This study evaluated the efficacy of a vaccine containing integral membrane glycoproteins from the intestine of Haemonchus contortus in calves challenged with H. contortus or Haemonchus placei. Males Holstein calves, raised worm free, were distributed into four groups with nine animals each. Two groups were vaccinated with 50 μg of antigen diluted on QuilA adjuvant, while the others two groups were the controls and received only adjuvant. The vaccine was administered three times 21 days apart. Either vaccinated or not and challenged with either 8,000 H. contortus or H. placei infective larvae. The calves were challenged 7 days after the last immunization and killed for worm counts 43 days later. Vaccination significantly reduced faecal egg counts (FEC) and worm burdens (P< 0.01). Antibody titres in the calves control stayed close to zero meanwhile in the calves vaccinated was observed high antibody titres in the serum. Calves vaccinated and challenged with H. contortus did not shed eggs in faecal samples, while the controls showed a maximum mean (± standard error) FEC of 61.1 (±42.3) at 31 days post infection. Then, FEC progressively declined in this group with only one animal shedding eggs in faeces 42 days post infection. With H. placei the controls FEC peaked at 35 days post infection (61.1 ±21.7) and remained relatively constant until the end of the study, while in the vaccinated group only two animals shed eggs and only on the last collection date. With H. placei the controls contained a mean of 551.1 (±93.7) parasites, while the vaccinates had 174.4 (±56.3) worms. The establishment rate of H. contortus was lower than that of H. placei (P< 0.01) with an average of 163.9 (±39.4) and 74.4 (±20.4) specimens in the control and vaccinated groups, respectively. It was concluded that vaccination of calves with antigens obtained from H. contortus conferred protection against both H. placei and H. contortus
Descrição
Palavras-chave
Bovino - Parasito - Imunologia, Haemonchus contortus, Vaccine
Como citar
BASSETTO, César Cristiano. Proteção de bovinos contra Haemonchus placei e Haemonchus contortus após imunização com antígenos oriundos da membrana intestinal de H. contortus. 2011. 42 f. Dissertação (mestrado) - Universidade Estadual Paulista, Instituto de Biociências de Botucatu, 2011.