Evaluation of local immune response to Fasciola hepatica experimental infection in the liver and hepatic lymph nodes of goats immunized with Sm14 vaccine antigen

Abstract

Protection against Fasciola hepatica in goats immunized with a synthetic recombinant antigen from Schistosoma mansoni fatty acid-binding protein 14 (rSm14) was investigated by assessing worm burdens, serum levels of hepatic enzymes, faecal egg count and hepatic damage, which was evaluated using gross and microscopic morphometric observation. The nature of the local immune response was assessed by examining the distribution of CD2+, CD4+, CD8+ and γ´+ T lymphocytes along with IgG+, IL-4+ and IFN-γ+ cells in the liver and hepatic lymph nodes (HLN). The goats used consisted of group 1 (unimmunized and uninfected), group 2 [infected control - immunized with Quillaia A (Quil A)] and group 3 (immunized with rSm14 in Quil A and infected), each containing seven animals. Immunization with rSm14 in Quil A adjuvant induced a reduction in gross hepatic lesions of 56.6% (p < 0.001) and reduced hepatic and HLN infiltration of CD2+, CD4+, CD8+ and γ´+ T lymphocytes as well as IL-4+ and IFN-γ+ cells (p < 0.05). This is the first report of caprine immunization against F. hepatica using a complete rSm14 molecule derived from S. mansoni. Immunization reduced hepatic damage and local inflammatory infiltration into the liver and HLN. However, considering that Quil A is not the preferential/first choice adjuvant for Sm14 immunization, further studies will be undertaken using the monophosphoryl lipid A-based family of adjuvants during clinical trials to facilitate anti-Fasciolavaccine development.

Development of the Brazilian Anti Schistosomiasis Vaccine Based on the Recombinant Fatty Acid Binding Protein Sm14 Plus GLA-SE Adjuvant

“…Further analysis confirmed these initial findings and also demonstrated that vaccination with rSm14 can protect the natural host of F. hepatica , the sheep, against experimental parasite challenge resulting in complete abolition of liver pathology ( 34 ). In independent experiments undertaken in Spain, protection against fasciola infection was later also achieved in goats immunized with rSm14, where again significantly reduced liver damage was recorded ( 35 ). Several groups around the world have been undertaking studies to evaluate the potential of FABPs homologous to Sm14 derived from various organisms as vaccines against a number of different helminth diseases.…”

Fasciola and fasciolosis in ruminants in Europe: Identifying research needs

“…However, numerous trials have shown no significant or discrete protection (Toet et al., ; Yap & Smooker, ). Some trials using recombinant antigens have shown very high protection, for example, a trial using recombinant Schistosoma mansoni 14 antigen (rSm14) in RIBI adjuvant, induced 98.5% protection in (Almeida et al., ), although the groups were small ( n = 4), and protection was not confirmed in subsequent trials in goats (Mendes et al., ). A second study used rLAP from F. hepatica given in different adjuvants in sheep, and led to a reduction in fluke burden of 74% and 86% with adjuvac 50 and alum adjuvant, respectively (Maggioli et al., ).…”

Fasciola hepaticaFatty Acid Binding Protein Inhibits TLR4 Activation and Suppresses the Inflammatory Cytokines Induced by Lipopolysaccharide In Vitro and In Vivo

“…Previous studies have shown that vaccines containing FABPs induce partial immune protection in experimentally infected mice and sheep (25, 26). Moreover, F. hepatica FABPs also appear to be important molecules for inducing cross-immunity against Schistosoma species (27). Although numerous published papers have explored the vaccine potential of F. hepatica FABPs, no studies have investigated whether FABPs have anti-inflammatory effects or whether they may interact with cells of the host immune system.…”