17 research outputs found
Identification of protective peptides of Fasciola hepatica-derived cathepsin L1 (FhCL1) in vaccinated sheep by a linear B-cell epitope mapping approach
Background: Fasciolosis is one of the most important parasitic diseases of livestock. The need for better control strategies
gave rise to the identification of various vaccine candidates. The recombinant form of a member of the cysteine
protease family, cathepsin L1 of Fasciola hepatica (FhCL1) has been a vaccine target for the past few decades since it
has been shown to behave as an immunodominant antigen. However, when FhCL1 was used as vaccine, it has been
observed to elicit significant protection in some trials, whereas no protection was provided in others.
Methods: In order to improve vaccine development strategy, we conducted a linear B-cell epitope mapping of
FhCL1 in sheep vaccinated with FhCL1, FhHDM, FhLAP and FhPrx plus Montanide and with significant reduction of
the fluke burden, sheep vaccinated with FhCL1, FhHDM, FhLAP and FhPrx plus aluminium hydroxide and with nonsignificant
reduction of the fluke burden, and in unvaccinated-infected sheep.
Results: Our study showed that the pattern and dynamic of peptide recognition varied noticeably between both
vaccinated groups, and that the regions 55–63 and 77–84, which are within the propeptide, and regions 102–114
and 265–273 of FhCL1 were specifically recognised only by vaccinated sheep with significant reduction of the fluke
burden. In addition, these animals also showed significant production of specific IgG2, whereas a scarce non-significant
production was observed in animals vaccinated with Aluminium hydroxide and no production was detected in
infected control animals.
Conclusions: We have identified 42 residues of FhCL1 that contributed to protective immunity against infection with
F. hepatica in sheep. Our results provide indications in relation to key aspects of the immune response. Given the variable
outcomes of vaccination trials conducted in ruminants to date, this study adds new insights to improve strategies
of vaccine development
Nuclear speckles:A model for nuclear organelles
Speckles are subnuclear structures that are enriched in pre-messenger RNA splicing factors and are located in the interchromatin regions of the nucleoplasm of mammalian cells. At the fluorescence-microscope level they appear as irregular, punctate structures, which vary in size and shape, and when examined by electron microscopy they are seen as clusters of interchromatin granules. Speckles are dynamic structures, and both their protein and RNA-protein components can cycle continuously between speckles and other nuclear locations, including active transcription sites. Studies on the composition, structure and behaviour of speckles have provided a model for understanding the functional compartmentalization of the nucleus and the organization of the gene-expression machinery