Immunization with the recombinant myosin regulatory light chain (FhrMRLC) in Adjuplex® adjuvant elicits a Th1-biased immune response and a reduction of parasite burden in Fasciola hepatica infected rats.

The aim of this study was to assess the immune response and the protective efficacy elicited by the vaccination with the recombinant Fasciola hepatica myosin regulatory light chain (FhrMRLC) in Adjuplex® adjuvant against the infection with F. hepatica in rats. Four groups of 15 animals each were used for the study, one group was immunized with the recombinant F. hepatica MRLC in Adjuplex® adjuvant and the other groups remained as adjuvant, positive and negative control groups. The parasitological study showed that a statistically significant reduction of 65.1% and 82.1% in fluke burden and fecal egg count, respectively, was detected in vaccinated animals. In addition, vaccination with FhrMRLC induced a well-defined humoral and cellular immune response characterized by a significant production of specific IgG and IL-2, IL-12, TNF-α and IFN-γ; which confirms the immunogenic capacity of the FhrMRLC.

Characterization and differential expression of cathepsin L3 alleles from Fasciola hepatica.

Fasciola hepatica infections cause significant global problems in veterinary and human medicine, including causing huge losses in cattle and sheep production. F. hepatica host infection is a multistage process and flukes express papain-like cysteine proteases, termed cathepsins, which play pivotal roles in virulence through host entry, tissue migration and immune evasion. Expression of these proteases is developmentally regulated. Recent studies indicate that excystment of infective larvae is dependent on cysteine proteases and together FhCL3 and FhCB account for over 80% of total protease activity detectable in newly excysted juvenile (NEJ) fluke. This paper focuses on members of the cathepsin L gene family, specifically those belonging to the CL3 clade. The cDNA of two novel cathepsin L3 proteases--FhCL3-1 and FhCL3-2 were cloned. The mRNA transcript expression levels for these enzymes were significantly different at various time points in life development stages obtained in vitro, from dormant metacercariae to NEJ 24h after excystment. Maximum expression levels were observed in NEJ immediately after excystment. In all stages examined by Real Time PCR, FhCL3-2 was expressed at a higher level compared to FhCL3-1 which was expressed only at very low levels. Western blot and immunohistochemical analysis also indicated higher expression of the FhCL3-2 allele and its secretory nature. The ability of antibody responses from rats and sheep challenged with F. hepatica to recognize recombinant FhCL3-1 and FhCL3-2 was shown to differ. Differences were also confirmed through the use of anti-rFhCL3-1 and anti-rFhCL3-2 sera in Western blot analysis of juvenile excretory/secretory (ES) material separated by 2D electrophoresis. These results indicate analysis of relative expression of parasite virulence factors from different populations is required, as this will likely impact the effectiveness of vaccines based on these antigens.

Increased AST/ALT ratio in azotaemic dogs infected with Babesia canis.

The AST/ALT ratio was estimated in 182 dogs infected with Babesia canis. Among these dogs 65 had anaemia and 68 were azotaemic. Student's t test was used to compare means of the AST/ALT ratio in anaemic and non-anaemic dogs, and in azotaemic and non-azotaemic dogs (p < 0.05). The differences in AST/ALT ratio between anaemic (1.52 +/- 1.15) and non-anaemic (1.76 +/- 1.34) dogs were statistically insignificant (p = 0.23), however, the comparison of AST/ALT ratio between azotaemic (2.68 +/- 1.52) and non-azotaemic (1.08 +/- 0.53) dogs revealed a significantly higher value of this index in azotaemic dogs (p = 0.00). The present results suggest that kidney injury contributed to increased AST activity in these dogs.