Bright Singh, I S; Kulkarni, A; Rombout, J H W M; Sudheer, N S; Vlak, J M; Caipang, C M A; Kiron, V; Brinchmann, M F(Elsevier, October 26, 2012)
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Abstract:
Several oral vaccination studies have been undertaken to evoke a better protection against white spot
syndrome virus (WSSV), amajor shrimp pathogen. Formalin-inactivated virus andWSSV envelope protein
VP28 were suggested as candidate vaccine components, but their uptake mechanism upon oral delivery
was not elucidated. In this study the fate of these components and of live WSSV, orally intubated to black
tiger shrimp (Penaeus monodon) was investigated by immunohistochemistry, employing antibodies
specific for VP28 and haemocytes. The midgut has been identified as the most prominent site of WSSV
uptake and processing. The truncated recombinant VP28 (rec-VP28), formalin-inactivated virus (IVP) and
live WSSV follow an identical uptake route suggested as receptor-mediated endocytosis that starts with
adherence of luminal antigens at the apical layers of gut epithelium. Processing of internalized antigens is
performed in endo-lysosomal compartments leading to formation of supra-nuclear vacuoles. However, the
majority of WSSV-antigens escape these compartments and are transported to the inter-cellular space via
transcytosis. Accumulation of the transcytosed antigens in the connective tissue initiates aggregation and
degranulation of haemocytes. Finally the antigens exiting the midgut seem to reach the haemolymph. The
nearly identical uptake pattern of the different WSSV-antigens suggests that receptors on the apical
membrane of shrimp enterocytes recognize rec-VP28 efficiently. Hence the truncated VP28 can be
considered suitable for oral vaccination, when the digestion in the foregut can be bypassed
Surekhamol, I S; Dr.Bright Singh,I S(Cochin University of Science and Technology, November , 2012)
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Abstract:
Aquaculture is a global industry providing food and employment thereby contributing to the economy. For the sustenance of aquaculture, disease management is a major requirement. Among the bacterial pathogens Vibrio harveyi remains to be the major one especially in shrimp culture systems. Rapid
and mass mortality of shrimp larvae due to Vibrio harveyi infection is well known, and the pathogen causes serious economic losses in grow out systems as well. It suggests that a well defined management strategy has to be built up to protect the crop from Vibrio harveyi infection in aquaculture systems. Antibiotics have been the choice for quite some times which led to residues in meat and development of multidrug resistant bacteria which invited ban on their application. In this context several alternate options have been thought off such as probiotics, immunostimulants and vaccines. Phage therapy is yet another option. Phages being natural parasites of bacteria and are abundant in aquatic environments their application to control bacterial pathogens in aquaculture has commendable potential in lieu of antibiotics. For that matter the therapeutic effect of phages has been proven in several antibiotic resistant pathogens inclusive of Vibrio harveyi.
Description:
National Centre for Aquatic Animal
Health, School of Environmental Studies, Cochin University of Science and Technology