Booster responses by oral vaccination with transgenic plants against chicken leucocytozoonosis

Abstract

We developed a transgenic potato (TrP/R7) expressing the recombinant R7 (rR7) antigen for use as an oral vaccine to protect against a chicken protozoan disease, chicken leucocytozoonosis. The TrP/R7 potato was produced by Agrobacterium tumefaciens-mediated transformation and regeneration, and the R7 gene insertion into potato chromosomes was confirmed by genomic polymerase chain reaction and Southern hybridization. rR7 antigen expression in TrP/R7 potato was also confirmed by sandwich enzyme-linked immunosorbent assay and western blotting using an antibody against the second-generation schizont of Leucocytozoon caulleryi. A transgenic potato clone with the highest rR7 antigen expression (3 mg rR7 antigen per gram of fresh-weight potato leaves) was selected, cultivated, and used in oral administration experiments to examine its ability to boost immunity. Chickens were immunized with chicken leucocytozoonosis vaccine ''Hokken'' by injection, and chickens that developed moderate levels of antibody titres were fed with TrP/R7 leaves. Chickens fed with TrP/R7 leaves showed increased antibody responses. In contrast, chickens fed with non-transgenic potato leaves showed a continuous decrease in antibody titres. Furthermore, chickens fed with TrP/R7 potato leaves showed strong resistance against experimental challenge with L. caulleryi infection. This study demonstrates the use of a plant-based oral vaccine to boost immunity against a protozoan disease.

The applicability of animal health surveillance systems for post-market monitoring of potential adverse effects of genetically modified (GM) feed

“…Surveillance Systems for Post Market Monitoring of GM Feed disease after feeding chickens with recombinant antigen expressing GM potatoes (40). Over 50% of the differences observed in these studies appear to be beneficial; as such, there is insufficient evidence to substantiate targeted surveillance in poultry.…”

Field evaluation of poultry red mite ( Dermanyssus gallinae ) native and recombinant prototype vaccines

“…Alternative oral delivery routes for avian vaccine antigens include delivery in food (e.g. Zhou et al, 2004 ; Jacob et al, 2013 , Ito et al, 2013 , Kolotilin et al, 2014 ) and a similar regime may be beneficial in maintaining a strong response to a PRM vaccine if the delivery method was to result in antigen-specific circulating serum antibodies.…”

Vaccination Against Poultry Parasites

“…Protective antibody titers last up to 5 mo after the injection, so a booster vaccination might be required to protect birds during the entire disease season (131,132). Oral administration of either the purified recombinant antigen or of the antigen expressed in transgenic plants has been used experimentally to boost immunity (131,133).…”