Humoral response (IgG) of goats experimentally infected with Fasciola hepatica against cysteine proteinases of adult fluke

Abstract

-The use of cysteine proteinases from Fasciola hepatica adult flukes for the serodiagnosis of caprine fasciolosis by means of an indirect ELISA test was studied. Two proteolytic fractions from adult fluke homogenates, with apparent molecular weights of 28 and 34 kDa (P28 and P34 respectively), were characterised as cysteine proteinases using azocasein assays and gelatin gel analysis. Both P28 and P34 fractions were electroluted and used as antigens in two different indirect ELISA tests. Serum IgG levels against P28 and P34 in goats given an experimental primary infection with 200 metacercariae or in goats given two experimental infections with 200 metacercariae were determined and compared with those observed in an uninfected control group. ELISA tests using both cysteine proteases showed a rapid and consistent detection of specific IgG in all experimentally infected goats. The IgG response to P28 was the first to be detected as early as 2-3 weeks post-infection and remained elevated throughout the experiment. The response to P34 was detected later (4-6 wpi) and disappeared in some animals at 18 wpi, while flukes were still present in the bile ducts. No significant differences were observed between the anti-P28 and anti-P34 IgG responses between animals receiving a primary or a challenge infection. The results of our study, although preliminary, are promising since the P28 ELISA described here may be a reliable method for the immunodiagnosis of F. hepatica infection in goats.Fasciola hepatica / cysteine proteinases / IgG / ELISA / goat

Immunoprotection in goats against Haemonchus contortus after immunization with cysteine protease enriched protein fractions

“…Haemonchus PBS soluble extracts were also checked for protease activity by gelatin gel electrophoresis as described by Ruiz et al [22]. Briefly, gelatin was incorporated into 12% gel slabs at a final concentration of 0.1%.…”

Development of Two Antibody Detection Enzyme-Linked Immunosorbent Assays for Serodiagnosis of Human Chronic Fascioliasis

“…Several F. hepatica purified antigens (17,18) and recombinant antigens have been employed to enhance the specificity of diagnostic assays (11,19,20). The most notable are cathepsin L, the major protease involved in F. hepatica virulence (21), fatty acid-binding proteins (FABPs) (22)(23)(24), and saposin-like proteins (FhSAP2) (25), which have been documented as useful immunodiagnostic antigens for serological detection of fascioliasis.…”

Biochemical Characterization and Differential Expression of a 16.5-Kilodalton Tegument-Associated Antigen from the Liver Fluke Fasciola hepatica

“…However, because of the high complexity of these antigenic extracts, cross-reactions with other parasites have been reported, diminishing the specificity of the techniques (14,20,38). Several F. hepatica recombinant antigens have been purified to enhance the specificity of the diagnostic assays (8,15,32,62). Some of these antigens have also been found to be excellent immunogens capable of inducing partial protection against a challenge F. hepatica infection in a variety of experimental models (1,3,9,21,28).…”