Short-term increase of body weight triggers immunological variables in dogs.

Overweight in dogs is, as in other companion animals, a major risk factor for several metabolic disorders. However, it is not yet known whether immunity is challenged by increased body weight in dogs. The aim of this study was to investigate the effect of a short-term increase in body weight on immunological variables in adult healthy beagle dogs. Sixteen dogs, divided into a control group (CG) and weight gain group (WGG), were included. During a period of 13 weeks, the CG was fed at maintenance energy requirement (MER), whereas the WGG received a double amount of food. After 13 weeks, blood samples were taken for immunological and biochemical analyses. Weight gain and increased body condition score in the WGG were accompanied by a significant higher leptin concentration. Weight gain increased the number of lymphocytes and immunoglobulins A and M and was responsible for a higher proliferation of peripheral blood mononuclear cells (PBMC). Short-term increase of body weight thus seems to trigger immunological variables in dogs.

Protection of pigs against Chlamydia trachomatis challenge by administration of a MOMP-based DNA vaccine in the vaginal mucosa.

Plasmid DNA (pWRG7079::MOMP) expressing the major outer membrane protein of a human Chlamydia trachomatis serovar E strain was tested for the ability to induce an immune response and protect against experimental genital infection with the same serovar. The vaccine was tested in pigs, as they are genetically and physiologically related to humans and suitable for studying C. trachomatis infection of the genital system. To increase the immune response, GM-CSF, LTA and B and CpG motives were used as adjuvants. GM-CSF was administered seven days before immunization, while the other adjuvants were administered together with the vaccine. Ten pigs were randomly divided into two groups. One group received an intravaginal primo-vaccination and a booster of 500 µg pWRG7079::MOMP, while the other group received the placebo vaccine pWRG7079. All animals were challenged with 10(8) TCID(50) of C. trachomatis serovar E. Pigs immunized with the DNA vaccine showed significantly less macroscopic lesions, vaginal excretion and chlamydial replication in the genital tract, as compared to placebo-vaccinated controls. However, infection could not be completely cleared.

Oral administration of beta-1,3/1,6-glucan Macrogard fails to enhance the mucosal immune response following oral F4 fimbrial immunisation in gnotobiotic pigs.

In this study gnotobiotic animals were used to see if the F4 fimbrial antigen of F4ac+ Escherichia coli is as immunogenic as in conventional pigs. In addition, the adjuvant effect of beta-1,3/1,6-glucans was analysed for the first time in germ-free domestic animals. Oral F4 immunisation of F4 receptor positive (F4R(+)) piglets was able to induce a systemic and mucosal immune response as conventional pigs, although less pronounced. Nevertheless, an IgA response was observed in Peyer's patches and mesenteric lymph nodes. Moreover, a dose dependent effect was observed. Oral administration of beta-glucans for 5 weeks was not able to enhance this F4-specific immune response. The only effect of the beta-glucan treatment we observed was a significantly higher IL-1 alpha mRNA expression in the spleen. No significant changes in total serum antibody concentrations and in the volume of the ileal Peyer's patches were seen.

Oral administration of beta-1,3/1,6-glucan to dogs temporally changes total and antigen-specific IgA and IgM.

The effect of oral administration of beta-1,3/1,6-glucans from Saccharomyces cerevisiae on humoral immunity in domestic dogs is not known. In this study, 15 beagle dogs were orally given MacroGard tablets, which contain 150 mg of this beta-glucan, daily for 4 weeks. At the end of this period, the total serum immunoglobulin A (IgA) level decreased significantly in the group treated with the glucan compared to that in the control group as well as compared to the concentrations before supplementation. In contrast, the total serum IgM level rose significantly, whereas no effect on the IgG level occurred. Similar changes were seen in Bordetella-specific IgA and IgM titers following vaccination during the supplementation period. The IgA concentration also became significantly lower in the saliva and tears of the glucan group than in the placebo group. The effects disappeared 1 week after the cessation of the supplementation. In conclusion, the results showed a temporary change in the isotype profile during glucan supplementation.

Porcine ulcerative dermatitis syndrome in sows: a form of vesicular cutaneous lupus erythematosus?

Severe ulcerative lesions were observed in the skin of two sows in a herd of 540 hybrid sows. Annular to polycyclic, severe crusting dermal ulcerations were found on the abdomen and flanks; moderate lesions were also found at the base of the tail and on the perineum. The lesions were histologically characterised as cell-poor interface dermatitis and folliculitis, basal cell vacuolisation, vesicle formation at the dermal-epidermal junction and serocellular crusts. A subepidermal mild to moderate band, characterised as a mixed inflammatory infiltrate, was present. A test for antinuclear antibodies was negative; however, immunofluorescence testing revealed a linear pattern of IgG precipitation in the skin. Staphylococcus hyicus was demonstrated in the serocellular crusts of one sow. Treatment with antibiotics, topical antiseptics and corticosteroids did not improve the sows' condition. Porcine circovirus and porcine respiratory and reproductive syndrome virus were not isolated from samples taken at postmortem examination. The observed gross lesions, the absence of response to treatment and the exclusion of other skin diseases suggested that the sows were affected with porcine ulcerative dermatitis syndrome.

Beta-glucans as immunostimulant in vertebrates and invertebrates.

Beta-glucans have been studied in animal species, from earthworms to humans. They are a heterogeneous group of glucose polymers found in fungi, plants, some bacteria, and sea weeds. The recognition of conserved microbial structures is a key aspect of metazoan immunity, and beta-glucans are emerging as major target for the recognition of fungal pathogens. However, the receptors and mechanisms by which this is achieved differ significantly between vertebrates and invertebrates. In this review, we will highlight the known receptors for beta-glucans and will discuss the various immune responses they can initiate, with some applications of these products, in both vertebrates and invertebrates.

Effect of beta-glucans on an ETEC infection in piglets.

The effect of orally administered beta-glucans in protecting pigs against an ETEC infection after weaning was analysed in this study. Three beta-glucans that differed in origin (Saccharomyces cerevisiae (MCG (Macrogard) and G2) or Sclerotium rolfsii (G3)) and/or extraction procedure were tested. Pigs fed for 2 weeks after weaning with these glucans were less susceptible to an F4+ ETEC infection in comparison with the control group. This was evidenced by a reduction in the faecal excretion of F4+ Escherichia coli as well as a reduced F4-specific serum antibody response. This decrease in faecal excretion was statistically significant for pigs fed with the MCG glucan in a first experiment and with the G3 glucan in a second experiment; diarrhoea was milder in the glucan-supplemented groups and was significantly reduced in the MCG-supplemented group. Furthermore, a lower amount of F4-specific IgM antibody-secreting cells (ASC) was found in the lymphoid tissues of pigs fed with G2 or G3 glucans in comparison with the control pig, as well as lower F4-specific IgA ASC in G3-fed pigs in comparison with the control pig. This study showed that beta-glucans can protect against an ETEC infection. Both MCG from S. cerevisiae and G3 from S. rolfsii, resulted in significant effects. To our knowledge, this is the first in vivo study, in which the use of beta-glucans as feed ingredient for just-weaned piglets was tested for their protective effects against ETEC infection.

Plasmid-encoded GM-CSF induces priming of the F4(K88)-specific serum IgA response by FaeG DNA vaccination in pigs.

We have used FaeG DNA to immunise piglets by the intradermal (ID) and the intramuscular (IM) route in a heterologous prime/boost model. ID immunisation with DNA resulted in a better induction of cellular immunity, whereas only the IM immunisation could prime an F4(K88)-specific serum IgA response. However, ID administration of plasmid-encoded GM-CSF 1 week before the ID immunisation enhanced the F4-specific humoral and cellular immune response and even primed the F4-specific IgA response more efficiently than the IM immunisation did.

Verifying simple arithmetic sums and products: are the phonological loop and the central executive involved?

In two experiments, we investigated the role of the phonological loop and the central executive in the verification of the complete set of one-digit addition (Experiment 1) and multiplication (Experiment 2) problems. The focus of the present study was on the contradictory results concerning the contribution of the phonological loop in the verification of true problems (e.g., 8 + 4 = 12 or 4 x 6 = 24) reported until now. The results revealed that this slave system is not involved in verifying simple arithmetic problems, in contrast to the central executive. Furthermore, our results indicated that the split effect is due to the use of two different arithmetic strategies.

The effect of cognitive load on saccadic eye movements.

The present study tested the hypothesis that, unlike prosaccades, antisaccades require controlled processing, due to the prepotent response that needs to be inhibited. The effect of the Random time Interval Generation (RIG) task (Vandierendonck, A., De Vooght, G., & Van der Goten, K. (1998). European Journal of Cognitive Psychology, 10, 413-444) on these saccade latencies and errors was studied. This task has the advantage that it loads executive processes, with only minimal interference with verbal or visuo-spatial components. A first experiment compared saccade performance within the prosaccade and the antisaccade task, executed alone and in combination with the RIG task and fixed tapping (added to exclude possible motor component interference explanations). A second experiment investigated the influence of task characteristics on the effects found. Although it was shown that antisaccades are more prone to interference of an executive interference task, it seems that prosaccades are also vulnerable. Interference on prosaccades could originate from a controlled execution of these saccades. A third experiment confirmed that endogenously generated prosaccades are susceptible to dual-task interference and showed that controlled saccade execution, without the need to inhibit a prepotent response, is sufficient to produce interference.

Parallel visual and memory processes.

We studied parallel processes: visual processes with the prosaccade, the no-saccade and the antisaccade task on the one hand and memory processes with the random tap task on the other hand. The random tap task is believed to be a pure interference task for the central executive component of working memory. The number of saccadic errors was found not to be influenced by taxing the central executive, while the latency times were significantly increased both in the prosaccade and in the antisaccade task. The effect seen in the antisaccade task was expected since it is a non-automatic activity under central executive control. Because the prosaccade task is an automatic activity, an effect of central executive load was not expected. As an explanation for our findings, we postulate that the prosaccade task is brought under willed control of the central executive.