Polymorphisms of the VDR gene are associated with presence of solar keratoses on the skin

Background Vitamin D has a range of biological effects including antiproliferative functions that are mediated through its receptors, encoded by the VDR gene. Objectives We investigated polymorphisms within the VDR gene for association with solar keratosis (SK), a biomarker for skin cancer, and examined interactions with skin phenotype. Methods Among participants of the community-based Nambour Skin Cancer Study, we genotyped 190 people with SKs and 190 without for ApaI, TaqI and FokI polymorphisms. Results We found a significant difference in genotype frequencies of the TaqI polymorphism between affected and unaffected populations (P = 0Æ008). The TT ⁄tt genotype group was associated with a twofold increase in odds of being affected by one or more SK. Individuals with fair skin and the TT ⁄tt genotype had about a sevenfold increase, whereas fair-skinned people with the Tt genotype had a fourfold increase in odds of being affected by SK. Individuals with the TT ⁄tt genotype who were prone to burn and not tan on acute sun exposure had about a sixfold increase in odds of SK. Fair-skinned people with VDR-Apa AA ⁄aa genotypes had about an eightfold increase in odds of being affected by SK compared with a fivefold increase in individuals with the Aa genotype and fair skin. Conclusions The trend for homozygote genotypes to increase the odds of SK suggests that intermediate VDR activity is important in protection or that the heterodimer formed by a heterozygous genotype may have an altered binding potential. Overall, these analyses indicate that VDR may be important in SK development

Field vaccination of sheep with a larval-specific antigen of the gastrointestinal nematode, Haemonchus contortus, confers significant protection against an experimental challenge infection

The availability of effective vaccines would add a valuable tool to the management of gastrointestinal nematode infections in livestock. While some experimental vaccines have shown protection in laboratory trials, few have been tested in the field. In the present study, eight month old sheep kept on pasture were treated with anthelmintic 8 weeks before vaccination with a larval surface antigen of the nematode parasite, Haemonchus contortus, under a commercially acceptable protocol, i.e. 2 immunizations using a commercial adjuvant; they were then given a controlled challenge infection 4 weeks later in indoor pens. Vaccination of sheep with 4 increasing doses of antigen resulted in significant reductions of 61% and 27% in cumulative faecal egg counts in the two highest dose groups, and a 69% reduction in worm burden in the highest dose group. Blood loss, as determined by packed cell volume, was also significantly reduced in the highest dose group of sheep. One outlier sheep showed an unusual increase in egg count without a concomitant increase in worm burden compared to the control sheep, indicating a vaccine-induced stress response. Antigen-specific serum antibody levels steadily increased in sheep while on pasture and decreased when transported to indoor pens. No difference in antibody levels could be detected between vaccinated and unvaccinated sheep, but all showed increased antibody levels compared to uninfected control sheep kept in indoors pens for 2–3 months, suggesting sheep were sensitized to the larval antigen either from low dose pasture contamination or cross reaction with pasture-related antigens. The results of these studies confirm the protective properties of the larval surface antigen and its protective effect when vaccinations are performed in the field

The effect of different adjuvants on immune parameters and protection following vaccination of sheep with a larval-specific antigen of the gastrointestinal nematode, Haemonchus contortus

It has recently been recognised that vaccine adjuvants play a critical role in directing the nature of a vaccine induced effector response. In the present study, several adjuvants were evaluated for their ability to protect sheep after field vaccination with the larval-specific Haemonchus contortus antigen, HcsL3. Using a suboptimal antigen dose, aluminium adjuvant was shown to reduce the cumulative faecal egg counts (cFEC) and worm burden by 23% and 25% respectively, in agreement with a previous study. The addition of Quil A to the aluminium-adjuvanted vaccine brought cFEC back to control levels. Vaccination with the adjuvant DEAE-dextran almost doubled the protection compared to the aluminium-adjuvanted vaccine resulting in 40% and 41% reduction in cFEC and worm counts compared to controls. Examination of skin responses following i.d. injection of exsheathed L3, revealed that cFEC was negatively correlated with wheal size and tissue eosinophils for the DEAE-dextran and aluminium-adjuvanted groups respectively. These studies have for the first time shown the potential of DEAE-dextran adjuvant for helminth vaccines, and discovered significant cellular correlates of vaccine-induced protection

Faecal egg counts and worm burden after challenge of vaccinated sheep.

<p>A: Mean (+SEM) daily eggs/gram faeces (EPG); B: Mean (+SEM) cumulative faecal egg count (FEC); C: individual and mean (+/−SEM) total worm counts. For details of experimental groups, refer to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0078357#pone-0078357-t001" target="_blank">Table 1</a>. Significantly different from the control group at p&lt;0.05 (*) or p&lt;0.01 (**).</p

Sheep numbers, immunization protocols and levels of protection against <i>H.contortus</i> infection.

<p>ND: not done; *p&lt;0.05, **p&lt;0.001.</p

Serum antibody responses after challenge of vaccinated sheep.

<p>Mean antibody isotype responses of sheep before vaccination (wk -8), 1 week after vaccination (wk -3), at day of challenge (wk 0) and 1 week after challenge (wk +1). Serum diluted 1/5000 (IgG1), 1/500 (IgG2), 1/20 (IgA) or 1/32 ammonium sulphate cut (IgE). For details of experimental groups, refer to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0078357#pone-0078357-t001" target="_blank">Table 1</a>. Dashed line represents the mean of a separate group of 8 sheep kept in indoor pens for 2–3 months. *Significant difference between group 3 and control group 1.</p

Correlations between parasitological and immunological parameters in control and vaccinated sheep.

*<p>Spearman rank correlation coefficient (P value); bold numbers indicate significance at P&lt;0.05. ND: not done.</p

Eosinophil infiltration after intradermal injection of saline or exsheathed L3 <i>H. contortus</i> larvae (xL3).

<p>Representative H&amp;E stained sections of skin tissue injected with saline (a) or xL3 (b) of group 1,2&amp;4 sheep. Group 3 sheep (Ag+DEAE-dextran) showed much higher eosinophil infiltration (c) and occasional granulomas (d).</p

Packed cell volume (PCV) of peripheral blood after challenge of vaccinated sheep.

<p>Mean (+SEM) PCV of groups at 49 days post infection (DPI). The mean PCV of all sheep before infection (day 0) was 34.2 (SD 2.3). For details of experimental groups, refer to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0078357#pone-0078357-t001" target="_blank">Table 1</a>.</p