Immunization of rats against Fasciola hepatica using crude antigens conjugated with Freund's adjuvant or oligodeoxynucleotides.

CERVI L, BORGONOVO J, EGEA M, CHIAPELLO L, MASIH D.

VETERINARY IMMUNOLOGY AND IMMUNOPATHOLOGY

ELSEVIER SCIENCE BV

Año: 2004 vol. 97 p. 97 - 104

0165-2427

Chronic Fasciola hepatica infection is correlated with the development of a T helper (Th2)-predominant immune response. To determine whether immunostimulatory CpG-containing oligodeoxynucleotides (CpG-ODN) or Freund´s complete adjuvant (FCA), known to promote a Th1 (T helper 1) immune responses, could provide protection from F. hepatica infection, total homogenate (TH) of F. hepatica mixed with CpG-ODN or FCA were injected subcutaneously (s.c.) into Wistar rats. A F. hepatica-specific Th1-predominant immune response was induced with CpG-ODN or FCA in lymph nodes of immunized animals. Lymph node cells from TH-CpG-ODN or TH-FCA immunized rats showed increased antigen-specific proliferation with high levels of INFgamma, compared to lymphocytes from rats injected with TH alone. In contrast, these two groups of immunized animals did not modify IL-4 release by draining lymph node cells, when they were subsequently stimulated with TH in vitro. However, a significant reduction in the burden of flukes (76.7%) was only observed in rats immunized with TH-FCA. Conversely, immunization of rats with TH-CpG-ODN did not promote protection against the parasite. Therefore, even though CpG-ODNs and FCA induced Th1 type responses, only FCA provided a significant protection to rats infected with F. hepatica.