Evaluation of the safety and efficacy of the novel Mycoplasma gallisepticum vaccine, Vaxsafe MG304, after spray-vaccination of 1-day-old specific pathogen-free chicks.

Mycoplasma gallisepticum causes chronic respiratory disease in poultry. A novel vaccine, Vaxsafe MG304 (the ts-304 strain), has greater protective efficacy in chickens than the Vaxsafe MG (strain ts-11) vaccine when delivered by eye drop at 3 weeks of age. Applying this vaccine in the hatchery to 1-day-old birds, using mass administration methods, would improve animal welfare and reduce labour costs associated with handling individual birds. This study assessed the protection provided by vaccination with Vaxsafe MG304 after administration to 1-day-old chicks. Chicks were administered a single dose of the vaccine to assess the efficacy of either a high dose (107.0 colour changing units, CCU) or a low dose (105.7 CCU) after eye drop or spray (in water or gel) administration against experimental challenge with virulent M. gallisepticum strain Ap3AS at 7 weeks of age. The vaccine was able to colonise the palatine cleft of chicks after vaccination by eye drop (at both doses) or by spray (in water or gel) (at the high dose). The high dose of vaccine, when delivered by eye drop or spray, was shown to be safe and induced a serological response and protective immunity (as measured by tracheal mucosal thickness and air sac lesion scores) against challenge. Vaccination of 1-day-old chicks with Vaxsafe MG304 by eye drop induced protective immunity equivalent to vaccination at 3 weeks of age. Vaxsafe MG304 was also protective when applied by both coarse- and gel spray methods at the higher dose and is therefore a suitable live attenuated vaccine for use in 1-day-old chicks.

Validation of folate in a convenient yeast assay suited for identification of inhibitors of Alzheimer's amyloid-beta aggregation.

Previously in the search for chemopreventatives for Alzheimer's disease (AD), microbial cells with amyloid-beta (Abeta) protein fusions have been used to screen for compounds that reduce the aggregation, misfolding or oligomerization of Abeta. In the current study, such a system has been used to look at the effect of folate, whose deficiency has been associated with AD. A folate-deficient yeast strain producing Abeta fused to green fluorescent protein (GFP) that spontaneously misfolds/aggregates and suppresses green fluorescence was used to examine the effects of folinic acid on Abeta-GFP fluorescence. At levels that did not affect growth or plasmid stability, increasing levels of folinic acid led to increasing green fluorescence, suggesting folate can assist with preventing Abeta-misfolding/aggregation. This result supports a protective role for folate and suggests that yeast assays may provide significant new approaches for testing of AD chemopreventatives.