Preliminary Evidence of Endotoxin Tolerance in Dairy Cows during the Transition Period

The blastogenic response of bovine peripheral blood mononuclear cells (PBMCs) to lipopolysaccharides (LPS) has been investigated for a long time in our laboratories. In particular, a possible correlation between the blastogenic response to LPS and the disease resistance of dairy cows has been suggested in previous studies. Isolated PBMCs from eight cows at three different time points during the transition period (T0 = 15 days before calving; T1 = 7 days post-calving; T2 = 21 days post-calving) were cultured in the presence or absence of LPS, and the blastogenic response was assayed 72 h after in vitro stimulation. Moreover, the gene expression of proinflammatory cytokines and kynurenine pathway molecules was investigated by real-time RT-PCR on both unstimulated and stimulated PBMCs. The cows were retrospectively divided into healthy and diseased, based on the development of peripartum diseases (subclinical ketosis and placenta retention). The comparison between healthy and diseased cows suggested that healthy animals seemed to better control the response to LPS. On the contrary, diseased animals showed a much higher inflammatory response to LPS. Moreover, cows were retrospectively classified as high and low responders based on the in vitro proliferative response of PBMCs to LPS, using the median value as a threshold. Unstimulated PBMCs of low responders showed higher expression of the proinflammatory cytokines Interleukin 1-β (IL-1β), Interleukin 6 (IL-6) and Tumor Necrosis Factor-α (TNF-α), compared to high responders. Our preliminary data suggest that, during the peripartum period, high responders seem to be more tolerant to endotoxins and develop a lower inflammatory response to different stressors. Instead, low responders could be more prone to the development of unwanted inflammatory conditions in response to mild/moderate stressors.

Taraxacum Officinale Alcoholic Extract Augments the Cell-Mediated Immune Response in Anti-Anthrax Vaccinated Sheep

Phytotherapy used various preparations in both human and veterinary medicine over time, due to their increased bioavailability and lower costs. Taraxacum officinale of Compositae family, well-known for its therapeutic effects, abundantly grows on Romanian pastures. The research aimed to investigate its alcoholic extract’s effects on cell-mediated immunity in anti-anthrax vaccinated, grazing sheep. Local Turcana ewes kept on pasture from spring to fall were sc vaccinated with R1190 attenuated anthrax strain, and blood was sampled before and 14 days after the vaccination. In vitro cell-mediated immunity was monitored employing phagocytosis and blast transformation tests in the presence of T. officinale alcoholic extract. The extract increased phagocytosis two weeks after the vaccination (p<0.001), while the blastogenic response also showed significant variations (p<0.05) over time. There was a positive effect of T. officinale extract on the cellular immunity, suggesting its stress alleviating effects in anti-anthrax vaccinated sheep.

Immunomodulatory effect of glucan on specific and nonspecific immunity after vaccination in puppies

The objective of the study was to determine the immunostimulatory effect of β-(1,3/1,6)-D-glucan in puppies. The effect exerted on the efficacy of vaccination, especially against canine parvovirus and rabies infection, was studied. The application of vaccine and glucan leads to significant increases in the nonspecific immunological parameters (phagocytic ability of leukocytes, blastogenic response of lymphocytes, metabolic and chemotactic activity of polymorphonuclear cells). The level of antibodies against canine parvovirus (Ab CPV) and rabies infection reached the most statistically significant values on the 28th day after the application of vaccine and a syrup containing β-(1,3/1,6)-D-glucan (Group GV) as compared to the control group (Group V, puppies receiving only vaccine). Dogs without glucan supplementation did not produce such significant levels of antibodies. We can conclude that glucan has relevant immunostimulatory effects in dogs with altered immunity. The glucan product tested in this study (PleraSAN V, PLEURAN, Bratislava, Slovakia) could be used in the small animal clinical practice.

Immune response in mice infected by Encephalitozoon cuniculi and suppressed by dexamethasone

Several indicators ofimmune response were observed in immunocompetent mice of the ICR line and those suppressed by dexamethasone upon their experimental infection with the microsporidia of Encephalitozoon cuniculi. The mice were infected by one-shot intraperitoneal administration of 5×107 pathogenic spores. On Days 7, 14, 28 and 42 after infection, peripheral blood leukocyte phagocytic activity was determined and compared, including phagocytic index and the blastogenic response in spleen cells to mitogenic activation by concanavalin A and phytohaemagglutinin. The results point to the fact that E. cuniculi itself can cause a significant decrease in phagocytic activity of phagocytic leukocytes in the early stages of infection as well as a remarkable decrease in the proliferative response of spleen cells to T-cellular mitogens.

Effect of ovariohysterectomy on canine postsurgical leukocyte function

The effect of surgery on phagocytic activity of blood leukocytes and mitogen-induced blastogenesis of lymphocytes was studied in fourteen dogs. Simple ovariohysterectomy with anaesthesia induced by ketamine and xylazine or by ketamine, xylazine and halothane caused a short nonsignificant depression of phagocytic activity that persisted for four hours after surgery. Ingestion capacity of leukocytes decreased significantly immediately after surgery. Mitogen-induced blastogenesis of lymphocytes was depressed significantly in the first 48 hours and despite partial recovery this parameter did not reach the value of the control groups until the end of observation (7 days). A more conspicuous decrease of blastogenic response of blood lymphocytes to mitogens was found after the use of ketamine and xylazine in a dose maintaining anaesthesia. Anaesthesia with ketamine and xylazine in the lower dose and maintained with halothane resulted in a later improvement of the blastogenic response of lymphocytes.

Effect of vitamin E and selenium on blood glutathione peroxidase activity and some immunological parameters in sheep

The objective of this study was to determine the effect of vitamin E and selenium administration on glutathione peroxidase (GSH-Px) activity and selected parameters of cellular immunity (metabolic activity, phagocytic activity, lymphocyte blastogenic response). Nine pregnant sheep with body weight of 42 to 66 kg were divided into two groups. Before lambing, the first group (n&nbsp;= 5) was given subcutaneously 5 mg vitamin E and 0.4 mg selenium per kg body weight while the second group (n&nbsp;= 4) was given no treatment and served as control. Blood samples from all sheep were collected before the treatment, 14 days after lambing and 30 days after lambing. Whole blood GSH-Px activities were significantly higher in the vitamin E and selenium treated sheep than in the control in the samples taken 14 days after lambing and 30 days after lambing (P&nbsp;&lt; 0.01;&nbsp;P&nbsp;&lt; 0.001, respectively). The evaluation of immunological parameters showed declines in immunological parameters measured on days 14 and 30 after lambing. The administered preparation led to significant effects (P&nbsp;&lt; 0.001;&nbsp;P&nbsp;&lt; 0.05) on phagocytic activity index of leukocytes and phagocytic activity index of neutrophils, respectively.