Construction of a Reporter Mycobacterium avium subsp. paratuberculosis (Map) Strain and Infection of Monocyte-Derived Macrophages from Cows Homozygous for SNP -298 A>G in the Macrophage Migration Inhibitory Factor (MIF) Gene

Abstract Text: Genetic factors influence resistance to Johne’s disease (JD). A single nucleotide polymorphism (SNP) located in the promoter of bovine macrophage migration inhibitory factor (MIF) (-298 A>G) was previously found to be associated with Mycobacterium avium subsp. paratuberculosis (Map) infection status. The objective was to determine if this SNP affects bovine macrophage function. In order to evaluate this, the gene encoding mCherry was cloned into the clinical isolate Map, then monocyte-derived macrophages (MDM) from healthy Holstein cows homozygous for genotypes MIF -298 AA (n=6) or GG (n=6) were infected with this Map isolate to determine MDM effector function. MIF secretion was also assessed in genotype-specific peripheral blood mononuclear cells (PBMC), monocytes and MDM following stimulation. Although MDM phagocytized the reporter Map, PBMC, monocytes and MDM expressed MIF following stimulation, genotype-specific differences were not detected.

Keywords:

Mycobacterium avium subsp. paratuberculosis (Map)

Macrophage migration inhibitory factor (MIF)

Single nucleotide polymorphism (SNP)