Mycoplasma bovis-induced inhibition of bovine peripheral blood mononuclear cell proliferation is ameliorated after blocking the immune-inhibitory programmed death 1 receptor

Mycoplasma bovis-induced immune suppression is a major obstacle faced by the host for controlling infections. M. bovis impairment of antigen-specific T-cell responses is achieved through inhibiting the proliferation of peripheral blood mononuclear cells (PBMCs). This impairment may contribute to the persistence of M. bovis infection in various sites, including lungs, and its systemic spread to various organs such as joints, with the underlying mechanisms remaining elusive. Here, we elucidated the role of the immune-inhibitory receptor programmed death 1 (PD-1) and its ligand (PD-L1) in M. bovis infection. Flow cytometry (FCM) analyses revealed an upregulation of PD-L1 expression on tracheal and lung epithelial cell lines after M. bovis infection. In addition, we found increased PD-L1 expression on purified lung lavage macrophages following M. bovis infection by FCM and determined its localization by immunofluorescence analysis comparing infected and control lung tissue sections. Moreover, M. bovis infection increased the expression of the PD-1 receptor on total PBMCs and in gated CD4+ and CD8+ T-cell subpopulations. We demonstrated that M. bovis infection induced a significant decrease in CD4+ PD-1INT and CD8+ PD-1INT subsets with intermediate PD-1 expression, which functioned as progenitor pools giving rise to CD4+ PD-1HIGH and CD8+ PD-1HIGH subsets with high PD-1 expression levels. We blocked PD-1 receptors on PBMCs using anti-PD-1 antibody at the beginning of infection, leading to a significant restoration of the proliferation of PBMCs. Taken together, our data indicate a significant involvement of the PD-1/PD-L1 inhibitory pathway during M. bovis infection and its associated immune exhaustion, culminating in impaired host immune responses. - 2018 American Society for Microbiology.This work was made possible by financial support from the Alberta Livestock and Meat Agency Ltd. and the Saskatchewan Agriculture Development Fund. We also thank Don Wilson and the VIDO Animal Care Unit for their invaluable help in obtaining blood and lung lavage samples.Scopu

Letters of introduction for Andrew Inglis Clark's visit to the U.S.A., 1897

Letters of introduction for Andrew Inglis Clark's visit to the U.S.A., 1897, from G.W. Bell, U.S. Consul, D.G. Thompson, F.W. Taussig, Margaret Windeyer of Western Australia, M.McMillan and T. Swan. Also menu of the Annual Dinner of the Reform Club. C4/C391 (1-13

Advances in prevention and therapy of neonatal dairy calf diarrhoea : a systematical review with emphasis on colostrum management and fluid therapy

Neonatal calf diarrhoea remains the most common cause of morbidity and mortality in preweaned dairy calves worldwide. This complex disease can be triggered by both infectious and non-infectious causes. The four most important enteropathogens leading to neonatal dairy calf diarrhoea are Escherichia coli, rota-and coronavirus, and Cryptosporidium parvum. Besides treating diarrhoeic neonatal dairy calves, the veterinarian is the most obvious person to advise the dairy farmer on prevention and treatment of this disease. This review deals with prevention and treatment of neonatal dairy calf diarrhoea focusing on the importance of a good colostrum management and a correct fluid therapy

Host innate immune responses and microbiome profile of neonatal calves challenged with Cryptosporidium parvum and the effect of bovine colostrum supplementation

IntroductionCalves are highly susceptible to gastrointestinal infection with Cryptosporidium parvum (C. parvum), which can result in watery diarrhea and eventually death or impaired development. With little to no effective therapeutics, understanding the host’s microbiota and pathogen interaction at the mucosal immune system has been critical to identify and test novel control strategies.MethodsHerein, we used an experimental model of C. parvum challenge in neonatal calves to describe the clinical signs and histological and proteomic profiling of the mucosal innate immunity and microbiota shifts by metagenomics in the ileum and colon during cryptosporidiosis. Also, we investigated the impact of supplemental colostrum feeding on C. parvum infection.ResultsWe showed that C. parvum challenged calves experienced clinical signs including pyrexia and diarrhea 5 days post challenge. These calves showed ulcerative neutrophil ileitis with a proteomic signature driven by inflammatory effectors, including reactive oxygen species and myeloperoxidases. Colitis was also noticed with an aggravated mucin barrier depletion and incompletely filled goblet cells. The C. parvum challenged calves also displayed a pronounced dysbiosis with a high prevalence of Clostridium species (spp.) and number of exotoxins, adherence factors, and secretion systems related to Clostridium spp. and other enteropathogens, including Campylobacter spp., Escherichia sp., Shigella spp., and Listeria spp. Daily supplementation with a high-quality bovine colostrum product mitigated some of the clinical signs and modulated the gut immune response and concomitant microbiota to a pattern more similar to that of healthy unchallenged calves.DiscussionC. parvum infection in neonatal calves provoked severe diarrheic neutrophilic enterocolitis, perhaps augmented due to the lack of fully developed innate gut defenses. Colostrum supplementation showed limited effect mitigating diarrhea but demonstrated some clinical alleviation and specific modulatory influence on host gut immune responses and concomitant microbiota

Calf health from birth to weaning. III. housing and management of calf pneumonia

Calfhood diseases have a major impact on the economic viability of cattle operations. A three part review series has been developed focusing on calf health from birth to weaning. In this paper, the last of the three part series, we review disease prevention and management with particular reference to pneumonia, focusing primarily on the pre-weaned calf. Pneumonia in recently weaned suckler calves is also considered, where the key risk factors are related to the time of weaning. Weaning of the suckler calf is often combined with additional stressors including a change in nutrition, environmental change, transport and painful husbandry procedures (castration, dehorning). The reduction of the cumulative effects of these multiple stressors around the time of weaning together with vaccination programmes (preconditioning) can reduce subsequent morbidity and mortality in the feedlot. In most studies, calves housed individually and calves housed outdoors with shelter, are associated with decreased risk of disease. Even though it poses greater management challenges, successful group housing of calves is possible. Special emphasis should be given to equal age groups and to keeping groups stable once they are formed. The management of pneumonia in calves is reliant on a sound understanding of aetiology, relevant risk factors, and of effective approaches to diagnosis and treatment. Early signs of pneumonia include increased respiratory rate and fever, followed by depression. The single most important factor determining the success of therapy in calves with pneumonia is early onset of treatment, and subsequent adequate duration of treatment. The efficacy and economical viability of vaccination against respiratory disease in calves remains unclear

Protocol for a systematic review of disease control strategies used to prevent infectious mortality and morbidity in pre-weaned beef calves

Beef Cattle Research Council, Results Driven Agriculture Research, and the University of Calgary Faculty of Veterinary MedicineIt is essential to optimize the production of calves in order to maximize economic returns to producers and the availability of feeder cattle and replacement stock for the industry. Morbidity and mortality in beef calves have negative impacts on beef operations and are associated with considerable economic damage (2,3). By implementing effective disease control strategies, morbidity and mortality caused by Bovine Respiratory Disease (BRD) and Neonatal Calf Diarrhea (NCD) may be reduced. Studies have shown that failed transfer of passive immunity (3–7), season of birth (8), herd size (2,3), assistance at calving (3,9), and purchasing adult cattle and using community pastures (10) are risk factors for morbidity and mortality in calves. Disease control strategies are an essential component of the health management of beef herds (11) and some preventive practices have shown financial benefits (12). Herd demographics and management practices alter the epidemiology of disease within the herd (13), with various strategies aiming to improve the animal environment, boost the immune system (14), and diminish animal exposure to potential pathogens (15). Risk factors associated with the multifactorial syndromes of BRD and NCD have been explored mainly in dairy calves (5–8), but there are a limited number of studies related to beef calves (16) and no efforts to summarize the available literature have been reported. A systematic review of the current scientific literature will be conducted focusing on colostrum management, vaccination strategies, biosecurity, biocontainment, metaphylactic use of antibiotics, and other strategies used to prevent mortality and morbidity caused by BRD and NCD in pre-weaned beef calves. To the best of our knowledge, there is no published systematic review on disease control strategies used in beef calves during the preweaning stage.Othe

Protocol for the systematic review of strategies used in beef cattle to prevent or control internal or external parasites

Funding for this project was obtained from the Beef Cattle Research Council (BCRC), Results Driven Agriculture Research (RDAR), and the University of Calgary Faculty of Veterinary Medicine (UCVM).This paper describes the protocol for a systematic review that will evaluate the following question: What strategies are most effective for the prevention or control of internal or external parasites in beef cattle herds? The overall objective of this systematic review is to critically assess and synthesize the current published knowledge on the aforementioned review question