Study of the local immune response to Fasciola hepatica in the liver and hepatic lymph nodes of goats immunised with a peptide of the Sm14 antigen

The nature of the local immune response was assessed studying the distribution of CD2+, CD4+, CD8+, γδ+ T lymphocytes, IgM+ B cells, IL-4+ and IFN-γ+ cells in the liver and hepatic lymph nodes (HLN) of goats immunised with a synthetic peptide of the Sm14 antigen from Schistosoma mansoni and challenged with Fasciola hepatica. A morphometric study of HLN was also carried out in order to evaluate the hyperplasia of lymphoid follicles. Despite the decrease in fluke burdens found in the immunised group (45.9%) respect to the infected control group, this difference was not statistically significant due to the high individual variability. In liver, a significant increase of CD2+, CD4+, CD8+, γδ+ T lymphocytes was found in the infected groups respect to the uninfected control and in the infected control respect to the immunised group. HLN showed a significant enlargement due to the hyperplasia of lymphoid follicles and infiltration of CD2+, CD4+, CD8+, γδ+ T lymphocytes in both infected groups respect to the uninfected control, with no significant differences between the infected control and immunised group. IFN-γ+ lymphoid cells was absent or very occasional in HLN where the number of IL-4+ cells was higher than that of IFN-γ, suggesting a polarized Th2 response in immunised and in infected control group.