Correlation of specific antibody titre and avidity with protection in cattle immunized against Fasciola hepatica
1998; Elsevier BV; Volume: 16; Issue: 9-10 Linguagem: Inglês
10.1016/s0264-410x(97)00289-2
ISSN1873-2518
Autores Tópico(s)Animal Nutrition and Physiology
ResumoCattle produce specific serum antibody mainly of the IgG1 isotype in response to infection with the liver fluke, Fasciola hepatica. In these animals a positive correlation between fluke-specific serum IgG1 levels and fluke-burden in non-immunized infected animals was observed. In contrast, immunization of cattle with a combination of the fluke-derived antigens cathepsin L2 (CL2) and fluke haemoglobin (FHb) in Freund's complete/incomplete adjuvant (FCAFIA) induced a· specific antibody response involving IgG2, as well as IgG1. These immunized animals also exhibited very high (72%) levels of protection against a subsequent challenge infection. When the vaccine was administered in FIA alone the specific antibody response, while still involving IgG1 and IgG2, was of lower magnitude (10-fold and 100-fold, respectively) and no significant reduction in fluke burden was observed following challenge. Nevertheless, in these animals, a strong IgG2 response was associated with low fluke burdens. These results provide further evidence of the non-protective nature of specific immune responses in cattle following F. hepatica infection, and demonstrate that vaccination can induce a qualitatively different, and protective, response.
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