Silica vesicles as nanocarriers and adjuvants for generating both antibody and T-cell mediated immune resposes to Bovine Viral Diarrhoea Virus E2 protein

Bovine Viral Diarrhoea Virus (BVDV) is widely distributed in cattle industries and causes significant economic losses worldwide annually. A limiting factor in the development of subunit vaccines for BVDV is the need to elicit both antibody and T-cell-mediated immunity as well as addressing the toxicity of adjuvants. In this study, we have prepared novel silica vesicles (SV) as the new generation antigen carriers and adjuvants. With small particle size of 50 nm, thin wall (similar to 6 nm), large cavity (similar to 40 nm) and large entrance size (5.9 nm for SV-100 and 16 nm for SV-140), the SV showed high loading capacity (similar to 250 mu g/mg) and controlled release of codon-optimised E2 (oE2) protein, a major immunogenic determinant of BVDV. The in vivo functionality of the system was validated in mice immunisation trials comparing oE2 plus Quil A (50 mu g of oE2 plus 10 mu g of Quil A, a conventional adjuvant) to the oE2/SV-140 (50 mu g of oE2 adsorbed to 250 mu g of SV-140) or oE2/SV-140 together with 10 mu g of Quil A. Compared to the oE2 plus Quil A, which generated BVDV specific antibody responses at a titre of 10(4), the oE2/SV-140 group induced a 10 times higher antibody response. In addition, the cell-mediated response, which is essential to recognise and eliminate the invading pathogens, was also found to be higher [1954-2628 spot forming units (SFU)/million cells] in mice immunised with oE2/SV-140 in comparison to oE2 plus Quil A (512-1369 SFU/million cells). Our study has demonstrated that SV can be used as the next-generation nanocarriers and adjuvants for enhanced veterinary vaccine delivery. (C) 2014 Elsevier Ltd. All rights reserved.

Prevalence and potential fitness cost of weak phosphine resistance in Tribolium castaneum (Herbst) in eastern Australia

The prevalence of resistance to phosphine in the rust-red flour beetle, Tribolium castaneum, from eastern Australia was investigated, as well as the potential fitness cost of this type of resistance. Discriminating dose tests on 115 population samples collected from farms from 2006 to 2010 showed that populations containing insects with the weakly resistant phenotype are common in eastern Australia (65.2 of samples), although the frequency of resistant phenotypes within samples was typically low (median of 2.3). The population cage approach was used to investigate the possibility that carrying the alleles for weak resistance incurs a fitness cost. Hybridized populations were initiated using a resistant strain and either of two different susceptible strains. There was no evidence of a fitness cost based on the frequency of susceptible phenotypes in hybridized populations that were reared for seven generations without exposure to phosphine. This suggests that resistant alleles will tend to persist in field populations that have undergone selection even if selection pressure is removed. The prevalence of resistance is a warning that this species has been subject to considerable selection pressure and that effective resistance management practices are needed to address this problem. The resistance prevalence data also provide a basis against which to measure management success.