In vitro investigation of bovine monocyte-derived macrophages with previously calculated immune response EBVs towards Mycobacterium avium subsp. paratuberculosis

Abstract

Johne’s disease is of high economic and welfare importance with a cost of £13 million to the UK cattle industry per year (Bond and Guitian, 2015). In addition, it is of zoonotic importance with studies suggesting a causal effect between Johne’s disease and Crohn’s disease in humans (Botsaris et al, 2016). Johne’s disease is caused by the Mycobacterium avium subsp. paratuberculosis (MAP) pathogen which results in a chronic enteric infection (Rue-Albrecht et al, 2014). There have been several management strategies applied to the control of Johne’s disease including biosecurity measures (NADIS, 2016), herd management (SAC, 2003), vaccination (NADIS, 2016 b) and targeted breeding (Minozzi et al, 2012). This study investigates the use of the High Immune Response (HIR) technology (Mallard et al, 2011) to identify cattle which have estimated breeding values (EBVs) capable of promoting resistance to MAP pathogens. The researcher completed this research study in vitro, macrophages were isolated from the blood of cattle with HIR tested EBV types and measured for immune response indicators (nitric oxide (NO) release and pH) (Owen, Punt and Stanford, 2013). The results of the laboratory tests were analysed using GenStat 18th Edition. Using a confidence level of 0.05 it was found that there were no statistically significant differences between the immune EBV types for NO release, however as predicted the high cell mediated immune response (CMIR) and high antibody mediated immune response (AMIR) (HH) macrophages produced more NO than the low (CMIR) and low (AMIR) (LL) macrophages. The contrast level of pH release between HH and LL macrophages was 0.061 and although not statistically significant the results did show that there was a difference between the EBV groups. The difference between high AMIR, low CMIR (HL) and low AMIR, high CMIR (LH) cattle EBVs, was found to be statistically significant in relation to pH with cattle that had a high response for cell mediated immune response reducing pH to a lower level and therefore exhibiting a mechanism to destroy MAP pathogens in vitro more successfully than the other EBVs. The difference between HH and LL macrophage pH release was not found to be statistically significant. It is suggested that this study should be repeated with a larger cohort of cattle over a longer period as this study was limited by small group size.

Date of Award	2016
Original language	English
Awarding Institution	Coventry University Royal Agricultural University
Sponsors	The Henry Plumb Foundation