Enzymatic activities of bovine peripheral blood leukocytes and milk polymorphonuclear neutrophils during intramammary inflammation caused by lipopolysaccharide

Early Detection of Sub-clinical Mastitis in Murrah Buffaloes through Udder Thermogram Analysis during the Natural Progression of Infection

Mastitis is a global production disease that needs an intelligent solution to tackle effectively. Infrared Thermography (IRT) is a non-invasive technology that could be incorporated into routine day-to-day farm activities to monitor the health status of the animals. In this study, the udder health status was routinely monitored for 30 days among 41 Murrah buffaloes via IRT and the California Mastitis Test (CMT). Further, somatic cell count (SCC), microbial identification, and milk quality parameters were also estimated for representative samples. The thermal imaging data obtained was tabulated and back propagated from the 0th day to the -10th day and front propagated from the 0th day to +10th day for all the udder quarters. Results revealed that on the 0th day, the mean of udder skin surface temperature (USST) and teat skin surface temperature (TSST) showed a difference (p < 0.05) in the sub-clinical mastitis (SCM) and clinical mastitis (CM) affected quarters to the healthy quarters, and their degree of difference was the highest. The indication of infection was signaled during the -9th to -5th day to the 0th day in SCM and CM cases. There was a steep increment in the temperature from -2nd and -1st day to the 0th day of infection. Sometimes, some quarters show an increment in temperature due to mastitis during morning hours but recover by evening milking due to the animal's innate immune system. Thus, the initiation period in which the udder gets assaulted is crucial in the early assessment of SCM by monitoring temperature change using IRT.

Subclinical Mastitis from Streptococcus agalactiae and Prototheca spp. Induces Changes in Milk Peptidome in Holstein Cattle

Early detection of bovine subclinical mastitis may improve treatment strategies and reduce the use of antibiotics. Herein, individual milk samples from Holstein cows affected by subclinical mastitis induced by S. agalactiae and Prototheca spp. were analyzed by untargeted and targeted mass spectrometry approaches to assess changes in their peptidome profiles and identify new potential biomarkers of the pathological condition. Results showed a higher amount of peptides in milk positive on the bacteriological examination when compared with the negative control. However, the different pathogens seemed not to trigger specific effects on the milk peptidome. The peptides that best distinguish positive from negative samples are mainly derived from the most abundant milk proteins, especially from β- and αs1-casein, but also include the antimicrobial peptide casecidin 17. These results provide new insights into the physiopathology of mastitis. Upon further validation, the panel of potential discriminant peptides could help the development of new diagnostic and therapeutic tools.

Effects of Water Extract from Artemisia argyi Leaves on LPS-Induced Mastitis in Mice

Simple Summary

Mastitis is a common disease in dairy cows. On the one hand, it will reduce milk yield and milk quality of dairy cows, thus increasing the cost of animal husbandry, and, on the other hand, it will influence the health of infected animals and even human beings. Generally speaking, because mastitis is caused by pathogenic microorganisms, antibiotic treatment is commonly used. However, antibiotic resistance of microorganisms caused by wrongful use of antibiotics and antibiotic residues after treatment has become an urgent problem to be solved. Chinese herbal medicines are pure natural substances, and many of them have antibacterial, anti-inflammatory, or immune-enhancing effects. In this experiment, Artemisia argyi (A. argyi) was selected as the research object to construct the cell model of cow mastitis. Studies have found that A. argyi extract can play a positive role in the regulation of inflammation, which is rich in organic acids and flavonoids. Therefore, A. argyi extract may be a potential treatment for mastitis.

Abstract

In the context of the unsatisfactory therapeutic effect of antibiotics, the natural products of plants have become a research hotspot. Artemisia argyi (A. argyi) is known as a traditional medicine in China, and its extracts have been reported to have a variety of active functions, including anti-inflammatory. Therefore, after establishing the mouse mastitis model by lipopolysaccharide (LPS), the effects of A. argyi leaves extract (ALE) were evaluated by pathological morphology of the mammary gland tissue, gene expression, and serum oxidation index. Studies have shown that ALE has a restorative effect on LPS-induced mammary gland lesions and significantly down-regulated the rise of myeloperoxidase (MPO) induced by LPS stimulation. In addition, ALE played a positive role in LPS-induced oxidative imbalance by restoring the activities of glutathione peroxidase (GSH-PX) and superoxide dismutase (SOD) and preventing the increase in nitric oxide (NO) concentration caused by the over-activation of total nitric oxide synthase (T-NOS). Further analysis of gene expression in the mammary gland showed that ALE significantly down-regulated LPS-induced up-regulation of inflammatory factors IL6, TNFα, and IL1β. ALE also regulated the expression of MyD88, a key gene for toll-like receptors (TLRs) signaling, which, in turn, regulated TLR2 and TLR4. The effect of ALE on iNOS expression was similar to the effect of T-NOS activity and NO content, which also played a positive role. The IκB gene is closely related to the NF-κB signaling pathway, and ALE was found to significantly alleviate the LPS-induced increase in IκB. All of these results indicated that ALE may be considered a potential active substance for mastitis.

The in vitro host cell immune response to bovine-adapted Staphylococcus aureus varies according to bacterial lineage

Mastitis is the most economically important disease affecting dairy cattle worldwide. Staphylococcus aureus is a highly prevalent cause of mastitis, causing infections ranging from sub-clinical to gangrenous. However, the interaction between the genotype of the infecting strain of S. aureus and the host response remains largely uncharacterised. To better understand the variation in presentation and outcomes of S. aureus-mediated bovine mastitis, we studied the interaction of a panel of mastitis isolates from several prominent bovine-associated lineages with bovine mammary epithelial cells (bMEC) and neutrophils. Significant differences in immune gene expression by infected primary or immortalised bMEC, or their elaboration of neutrophil chemoattractants, were observed and were dependent on the lineage of the infecting strain. Differences were also apparent in the invasiveness of S. aureus strains and their ability to survive killing by neutrophils. Our results demonstrate that a range of immune responses occur, suggesting the importance of S. aureus strain in dictating mastitis disease course. S. aureus lineages may therefore have adopted differing strategies for exploitation of the intramammary niche. Consequently, improved diagnosis of infecting lineage may enable better prognosis for S. aureus mastitis and reduce morbidity and economic loss.

Proteolytic Systems in Milk: Perspectives on the Evolutionary Function within the Mammary Gland and the Infant

Milk contains elements of numerous proteolytic systems (zymogens, active proteases, protease inhibitors and protease activators) produced in part from blood, in part by mammary epithelial cells and in part by immune cell secretion. Researchers have examined milk proteases for decades, as they can cause major defects in milk quality and cheese production. Most previous research has examined these proteases with the aim to eliminate or control their actions. However, our recent peptidomics research demonstrates that these milk proteases produce specific peptides in healthy milk and continue to function within the infant's gastrointestinal tract. These findings suggest that milk proteases have an evolutionary function in aiding the infant's digestion or releasing functional peptides. In other words, the mother provides the infant with not only dietary proteins but also the means to digest them. However, proteolysis in the milk is controlled by a balance of protease inhibitors and protease activators so that only a small portion of milk proteins are digested within the mammary gland. This regulation presents a question: If proteolysis is beneficial to the infant, what benefits are gained by preventing complete proteolysis through the presence of protease inhibitors? In addition to summarizing what is known about milk proteolytic systems, we explore possible evolutionary explanations for this proteolytic balance.

The Immunology of Mammary Gland of Dairy Ruminants between Healthy and Inflammatory Conditions

The health of dairy animals, particularly the milk-producing mammary glands, is essential to the dairy industry because of the crucial hygienic and economic aspects of ensuring production of high quality milk. Due to its high prevalence, mastitis is considered the most important threat to dairy industry, due to its impacts on animal health and milk production and thus on economic benefits. The MG is protected by several defence mechanisms that prevent microbial penetration and surveillance. However, several factors can attenuate the host immune response (IR), and the possession of various virulence and resistance factors by different mastitis-causing microorganisms greatly limits immune defences and promotes establishment of intramammary infections (IMIs). A comprehensive understanding of MG immunity in both healthy and inflammatory conditions will be an important key to understand the nature of IMIs caused by specific pathogens and greatly contributes to the development of effective control methods and appropriate detection techniques. Consequently, this review aims to provide a detailed overview of antimicrobial defences in the MG under healthy and inflammatory conditions. In this sense, we will focus on pathogen-dependent variations in IRs mounted by the host during IMI and discuss the potential ramifications of these variations.

Predicting the important enzymes in human breast milk digestion

Human milk is known to contain several proteases, but little is known about whether these enzymes are active, which proteins they cleave, and their relative contribution to milk protein digestion in vivo. This study analyzed the mass spectrometry-identified protein fragments found in pooled human milk by comparing their cleavage sites with the enzyme specificity patterns of an array of enzymes. The results indicate that several enzymes are actively taking part in the digestion of human milk proteins within the mammary gland, including plasmin and/or trypsin, elastase, cathepsin D, pepsin, chymotrypsin, a glutamyl endopeptidase-like enzyme, and proline endopeptidase. Two proteins were most affected by enzyme hydrolysis: β-casein and polymeric immunoglobulin receptor. In contrast, other highly abundant milk proteins such as α-lactalbumin and lactoferrin appear to have undergone no proteolytic cleavage. A peptide sequence containing a known antimicrobial peptide is released in breast milk by elastase and cathepsin D.

Role of somatic cells on dairy processes and products: a review

Somatic cells are an important component naturally present in milk, and somatic cell count is used as an indicator of udder health and milk quality. The role of somatic cells in dairy processes and products is ill-defined in most studies because the role of these cells combines also the concomitance of physicochemical modifications of milk, bacterial count, and the udder inflammation in the presence of high somatic cell count. The aim of this review is to focus on the role of somatic cells themselves and of endogenous enzymes from somatic cells in milk, in dairy transformation processes, and in characteristics of final products overcoming biases due to other factors. The immune function of somatic cells in the udder defense and their protective role in milk will be primarily considered. Different characteristics of milk induced by various somatic cell counts, types, and their endogenous enzymes influencing directly the technological properties of milk and the final quality of dairy products will be discussed as well. By comparing methods used in other studies and eliminating biases due to other factors not considered in these studies, a new approach has been suggested to evaluate the effective role of somatic cells on dairy processes and products. In addition, this new approach allows the characterization of somatic cells and their endogenous enzymes and, in future research, will allow the clarification of mechanisms involved in the release of these components from somatic cells during dairy processes, particularly in cheese technologies.

Transfer of immunoglobulins through the mammary endothelium and epithelium and in the local lymph node of cows during the initial response after intramammary challenge with E. coli endotoxin

BACKGROUND

The first hours after antigen stimulation, interactions occur influencing the outcome of the immunological reaction. Immunoglobulins originate in blood and/or are locally synthesized. The transfer of Ig isotypes (Igs) in the udder has been studied previously but without the possibility to distinguish between the endothelium and the epithelium. The purpose of this study was to map the Ig transfer through each barrier, separately, and Ig transfer in the local lymph nodes of the bovine udder during the initial innate immune response.

METHODS

The content of IgG1, IgG2, IgM, IgA and albumin (BSA) was examined in peripheral/afferent mammary lymph and lymph leaving the supramammary lymph nodes, and in blood and milk before (0 h) and during 4 hours after intramammary challenge with Esherichia coli endotoxin in 5 cows.

RESULTS

Igs increased most rapidly in afferent lymph resulting in higher concentrations than in efferent lymph at postinfusion hour (PIH) 2, contrary to before challenge. Ig concentrations in milk were lower than in lymph; except for IgA at 0 h; and they increased more slowly. Afferent lymph:serum and efferent lymph:serum concentration ratios (CR) of Igs were similar to those of BSA but slightly lower. Milk:afferent lymph (M:A) CRs of each Ig, except for IgG2, showed strikingly different pattern than those of BSA. The M:A CR of IgG1, IgM and IgA were higher than that of BSA before challenge and the CR of IgA and IgG1 remained higher also thereafter. At PIH 2 there was a drop in Ig CRs, except for IgG2, in contrast to the BSA CR which gradually increased. The M:A CR of IgM and Ig A decreased from 0 h to PIH 4, in spite of increasing permeability.

CONCLUSION

The transfer of Igs through the endothelium appeared to be merely a result of diffusion although their large molecular size may hamper the diffusion. The transfer through the epithelium and the Ig concentrations in milk seemed more influenced by selective mechanisms and local sources, respectively. Our observations indicate a selective mechanism in the transfer of IgG1 through the epithelium also in lactating glands, not previously shown; a local synthesis of IgA and possibly of IgM, released primarily into milk, not into tissue fluid; that IgG2 transfer through both barriers is a result of passive diffusion only and that the content of efferent lymph is strongly influenced by IgG1, IgM and IgA in the mammary tissue, brought to the lymph node by afferent lymph.

Inflammatory effect of cleaved bovine lactoferrin by elastase on staphylococcal mastitis

Elastase activity and concanavalin A (Con A) low affinity bovine lactoferrin (bLf) molecule were detected in mammary gland secretions (MGSs) from mammary glands (MGs) with clinical staphylococcal mastitis. Changes in clinical symptoms correlated with increases in both elastase activity and the concentration of Con A low-affinity Lf in MGSs from mastitic MGs. Bovine Lf treated with elastase (elastase-Lf) showed various small bLf molecules and the same image on Con A two-dimensional immunoelectrophoresis as low Con A affinity bLf in MGSs. We confirmed the presence of four common bLf peptides for the elastase-bLf and low Con A affinity bLf molecules in mastitic MGSs, and synthesized four peptides. Strong mRNA expression of interleukin-6 (IL-6), tumor necrosis factor alpha (TNFalpha), interleukin-8 (IL-8), and monocyte chemotactic protein-1 (MCP-1) was induced in bovine mammary epithelial cells on stimulation with low Con A affinity bLf, elastase-bLf, and GQRDLLFKDSAL, a synthesis bLf peptide based on nuclear factor kappa B (NFkappaB) activation. These results suggest that bLf was cleaved by elastase, and that this cleavage changed the physical function of Lf. Our results indicate that elastase induced production of low Con A affinity bLf, including the bLf peptide GQRDLLFKDSAL, and had an inflammatory effect on staphylococcal mastitis.

Cytokine response of bovine mammary gland epithelial cells to Escherichia coli, coliform culture filtrate, or lipopolysaccharide

OBJECTIVE

To define the cytokine response of a cultured mammary gland epithelial cell line (ie, Mac-T) when incubated with Escherichia coli or its products.

SAMPLE POPULATION

Mac-T cells and E coli from cows with mastitis.

PROCEDURE

Mac-T cells were incubated with E coli or its products. The cytokine response of Mac-T cells to these treatments was quantified by measuring mRNA content of interleukin (IL)-1alpha, IL-1beta, IL-8, and tumor necrosis factor (TNF)-alpha by use of a quantitative reverse transcriptase-polymerase chain reaction assay. The amount of TNF-alpha secreted was also measured.

RESULTS

Treatment with E coli or its products resulted in significant increases in IL-1alpha, IL-8, and TNF-alpha mRNA content in Mac-T cells. This increase was reversible when culture filtrate was incubated with polymyxin B. The amount of IL-1beta mRNA in Mac-T cells increased only slightly over baseline after treatment with E coli or its products, but this increase was not diminished by incubation of E coli filtrate with polymyxin B.

CONCLUSIONS AND CLINICAL RELEVANCE

Incubation of Mac-T cells with E coli or its products resulted in increased amounts of IL1alpha, IL-8, and TNF-alpha mRNA. Inhibition of this response by incubation of culture filtrate with polymyxin B suggested that lipopolysaccharide was the main bacterial product that stimulated the cytokine response. The small increase in IL-1beta content in Mac-T cells incubated with E coli or its products suggested that this cytokine had a smaller role in the Mac-T cell response to E coli.

A new diagnostic indicator using concanavalin a low-affinity lactoferrin levels in mammary gland secretion in mastitic drying cows

We examined the effective diagnostic indicator using the concanavalin A (Con A) low-affinity lactoferrin (Lf) to mastitic drying cows. The concentrations of both Lf and Con A low-affinity Lf in mammary gland secretions (MGSs) were lower than normal MGSs at the early and middle dry periods and colostrums. On the other hand, the levels of Con A low-affinity Lf in MGSs increased following the appearance of mastitis symptoms, and decreased when the mastitic symptoms were cured. Moreover, IgG1 concentrations of colostrums decrease on the quarters where a high level of Con A low-affinity Lf was determined after the onset of dry period. These results suggest that this method could be used as a useful indicator to mastitic drying cows.