Immunomodulatory Effects of Bacterial Toll-like Receptor Ligands on the Phenotype and Function of Milk Immune Cells in Dromedary Camel

(1) Toll-like receptors (TLR) are a family of pattern recognition receptors that sense distinct molecular patterns of microbial origin. Although the immune cell composition of camel milk has been recently described, host-pathogen interaction studies in the camel mammary gland are still scarce. The present study aimed to use a whole milk stimulation assay for investigating the modulatory effect of selected Toll-like receptor (TLR) ligands on the phenotype and function of milk immune cells. (2) Methods-camel milk samples (n = 7) were stimulated in vitro with the TLR4 ligand LPS or the TLR2/1 ligand Pam3CSK4, and separated milk cells were evaluated for stimulation-induced shape change, the expression of cell surface markers, phagocytosis, apoptosis, ROS production, and NETosis. Stimulation with PMA was used as a control stimulation. (3) Results-all stimulants induced shape change in milk cells, change in the expression of several cell markers, and increased cell apoptosis and NETosis. In addition, stimulation with Pam3CSK4 and PMA was associated with enhanced ROS production, while only PMA stimulation resulted in enhanced bacterial phagocytosis by milk immune cells. (4) Conclusions-our data indicates selective modulating effects of the TLR ligands LPS and Pam3CSK4 on camel milk phagocytes. These results may have implications for the use of synthetic TLR agonists as immunomodulatory adjuvants of the immune response to intra-mammary vaccines against mastitis pathogens.

Quantitative Proteomic Analysis Reveals Yeast Cell Wall Products Influence the Serum Proteome Composition of Broiler Chickens

With an ever-growing market and continual financial pressures associated with the prohibition of antibiotic growth promoters, the poultry industry has had to rapidly develop non-antibiotic alternatives to increase production yields. A possible alternative is yeast and its derivatives, such as the yeast cell wall (YCW), which have been proposed to confer selected beneficial effects on the host animal. Here, the effect of YCW supplementation on the broiler chicken was investigated using a quantitative proteomic strategy, whereby serum was obtained from three groups of broilers fed with distinct YCW-based Gut Health Products (GHP) or a control basal diet. Development of a novel reagent enabled application of ProteoMiner™ technology for sample preparation and subsequent comparative quantitative proteomic analysis revealed proteins which showed a significant change in abundance (n = 167 individual proteins; p < 0.05); as well as proteins which were uniquely identified (n = 52) in, or absent (n = 37) from, GHP-fed treatment groups versus controls. An average of 7.1% of proteins showed changes in abundance with GHP supplementation. Several effects of these GHPs including immunostimulation (via elevated complement protein detection), potential alterations in the oxidative status of the animal (e.g., glutathione peroxidase and catalase), stimulation of metabolic processes (e.g., differential abundance of glyceraldehyde-3-phosphate dehydrogenase), as well as evidence of a possible hepatoprotective effect (attenuated levels of serum α-glutathione s-transferase) by one GHP feed supplement, were observed. It is proposed that specific protein detection may be indicative of GHP efficacy to stimulate broiler immune status, i.e., may be biomarkers of GHP efficacy. In summary, this work has developed a novel technology for the preparation of high dynamic range proteomic samples for LC-MS/MS analysis, is part of the growing area of livestock proteomics and, importantly, provides evidential support for beneficial effects that GHP supplementation has on the broiler chicken.

Milk Immune Cell Composition in Dromedary Camels With Subclinical Mastitis

Mastitis represents one of the most important infectious diseases in camels with heavy economic losses due to reduced milk quantity and quality. Balanced immune cell composition and function in the mammary gland are essential for effective immune response to mastitis pathogens. The objective of the present study was to characterize the cellular immune response to subclinical mastitis in the mammary gland of dromedary camels. Therefore, immunostaining and flow cytometry were used to compare the cellular composition, leukocyte phenotype, and cell viability in camel milk from healthy she-camels (n = 8) and she-camels with subclinical mastitis (SCM; n = 6). In addition, the ex vivo phagocytic activity of milk phagocytes was compared between healthy and affected animals. The health status of the mammary gland was evaluated based on the California Mastitis Test (CMT) score. SCM (CMT score of ≥3 in the absence of clinical signs of mastitis) was found in six of the 56 sampled quarters (10.7 %) with only one affected quarter per animal. In comparison to milk from healthy camels, milk from SCM animals showed higher somatic cell count (SCC), higher numbers of CD45+ leukocytes with an expanded fraction of CD172a+ myeloid cells. Within the myeloid cell population, there was an increase in the percentage of granulocytes (CD172a⁺CD14^low) with a decreased percentage of macrophages (CD172a⁺CD14^high) in milk from affected animals compared to healthy animals. The decrease in lymphoid cells in SCM milk was mainly due to the decreased fraction of CD4+ helper T cells. Camel SCM was also associated with a stimulated phenotype, increased cell viability, and enhanced phagocytic activity of the milk phagocytes, macrophages and granulocytes. Collectively, the present study identified significant changes in SCC, leukocyte count, phenotype, viability, and function in association with subclinical mastitis in camels. The results of the present study support a better understanding of host-pathogen interaction mechanisms in the camel mammary gland.

Application of the TruCulture® whole blood stimulation system for immune response profiling in cattle

Capturing the phenotypic variation in immune responses holds enormous promise for the development of targeted treatments for disease as well as tailored vaccination schedules. However, accurate detection of true biological variation can be obscured by the lack of standardised immune assays. The TruCulture® whole blood stimulation system has now been extensively used to detect basal and induced immune responses to a range of pathogen-associated molecular patterns (PAMPs) in human peripheral blood. This study demonstrates the optimisation of this commercially available assay for systemic immune phenotyping in cattle. The early immune response in Holstein-Friesian bull calves (n = 10) was assessed by haematology, flow cytometry and cytokine expression profiling after 24 h ex-vivo PAMP (LPS, poly (I:C) and zymosan) stimulation in TruCulture® tubes. A comparative analysis was also performed with a traditional whole blood stimulation assay and cell viability using both systems was also evaluated. Results: Supernatant collected from TruCulture® tubes showed a significant increase in IL-1β and IL-8 expression compared to null stimulated tubes in response to both LPS and zymosan. In contrast, a detectable immune response was not apparent at the standard concentration of poly (I:C). Conventional whole blood cultures yielded similar response profiles, although the magnitude of the response was higher to both LPS and zymosan, which may be attributed to prokaryotic strain-specificity or batch of the stimulant used. Despite being a closed system, HIF1A expression - used as a measure of hypoxia was not increased, suggesting the TruCulture® assay did not negatively affect cell viability. This represents the first reported use of this novel standardised assay in cattle, and indicates that the concentration of poly (I:C) immunogenic in humans is insufficient to induce cytokine responses in cattle. We conclude that the low blood volume and minimally invasive TruCulture® assay system offers a practical and informative technique to assess basal and induced systemic immune responses in cattle.

Experimentally induced mastitis and metritis modulate soy bean derived isoflavone biotransformation in diary cows

The present study compared the changes in isoflavone (daidzein and genistein) and their metabolite (equol and para-ethyl-phenol) concentrations in the blood plasma of cows with induced mastitis and metritis after feeding with soy bean. Sixteen cows were divided into four groups: control for mastitis group, cows with induced mastitis group, control for metritis group, and cows with induced metritis group. All cows were fed a single dose of 2.5 kg of soy bean and then blood samples were taken from the jugular vein for 8 h at predetermined intervals. The concentrations of soy bean-derived isoflavones and their active metabolites were measured in the blood plasma on HPLC system. β-Glucuronidase activity in the blood plasma of cows was measured by fluorometric method. In the blood plasma of cows with induced mastitis and metritis, we found considerably higher concentrations and time-dependent increase in isoflavone metabolites (equol and para-ethyl-phenol) with reference to cyclic cows (P < 0.05). Moreover, we noticed significant decrease of genistein in the blood plasma of the cows with induced metritis compared with control cows (P < 0.05). In addition, in the blood plasma of the cows with induced metritis, we found an increase in β-glucuronidase activity compared with control cows (P < 0.05). In conclusion, health status of the females influenced the concentrations of isoflavone metabolites in the blood plasma of the cows. Experimentally induced mastitis and metritis increased isoflavone absorption, biotransformation and metabolism. Therefore, we suggest that cows with induced mastitis and metritis are more exposed to active isoflavone metabolite actions than healthy cows.

Effect of Panax ginseng on cytokine expression in bovine mammary glands at drying off

Biological response modifiers (BRM) are agents that modify the host's response to pathogens with resultant beneficial prophylactic or therapeutic effects. The objectives of this study were to describe the immunomodulatory effects of Panax ginseng (GS) on bovine mammary glands at the end of lactation. Eight mammary quarters from six nonpregnant cows in late lactation were infused with 10mL of BRM (3mg/mL), six quarters were treated with placebo (vehicle alone) and six quarters were maintained as uninoculated controls. Milk samples were collected at different time points for detection of specific cytokines mRNA by RT-PCR and Western blotting assay. A significant increase of IL-1α, IL-1β and TNF-α mRNA expression was observed in BRM-treated compared with placebo-treated quarters at 48h post-treatment (pt) (P<0.05). A 17kDa TNF-α band expressed a sharp elevation at 24h and reduction in its level at 48h pt in BRM-treated quarters. Differences in this cytokine level between 24 and 48h pt times were significant (P<0.05). GS extract inoculation at drying off was associated with somatic cell counts increase, cytokines mRNA transcription and the presence of TNF-α in milk and can therefore exert immunomodulating effects in bovine mammary gland at drying off.

Dietary supplementation of mannan-oligosaccharide enhances neonatal immune responses in chickens during natural exposure to Eimeria spp

Background

Control and eradication of intestinal infections caused by protozoa are important biomedical challenges worldwide. Prophylactic control of coccidiosis has been achieved with the use of anticoccidial drugs; however, the increase in anticoccidial resistance has raised concerns about the need for new alternatives for the control of coccidial infections. In fact, new strategies are needed to induce potent protective immune responses in neonatal individuals.

Methods

The effects of a dietary supplementation of mannan-oligosaccharide (yeast cell wall; YCW) on the local, humoral and cell-mediated immune responses, and intestinal replication of coccidia were evaluated in a neonatal animal model during natural exposure to Eimeria spp. A total of 840 one-day-old chicks were distributed among four dietary regimens: A) Control diet (no YCW) plus anticoccidial vaccine); B) Control diet plus coccidiostat; C) YCW diet plus anticoccidial vaccination; and D) YCW diet plus coccidiostat. Weight gain, feed consumption and immunological parameters were examined within the first seven weeks of life.

Results

Dietary supplementation of 0.05% of YCW increased local mucosal IgA secretions, humoral and cell-mediated immune responses, and reduced parasite excretion in feces.

Conclusion

Dietary supplementation of yeast cell wall in neonatal animals can enhance the immune response against coccidial infections. The present study reveals the potential of YCW as adjuvant for modulating mucosal immune responses.