Circulating microRNAs associated with immune competence in Angus cattle

Area of Science:

• Veterinary Immunology
• Livestock Genetics
• Molecular Biology

Background:

• Immune competence (IC) is crucial for livestock health and disease resistance.
• Selective breeding for IC traits aims to improve disease combatting abilities.
• Host-encoded circulating microRNAs (miRNAs) are increasingly recognized as regulators of immune responses.

Purpose of the Study:

• To investigate the association between circulating miRNAs and immune responses to vaccination in Australian Angus steers.
• To identify potential miRNA biomarkers for immune competence (IC) in livestock.
• To explore the role of miRNAs in vaccine-induced immunity.

Main Methods:

• Phenotyping of immune competence (IC) based on antibody (Ab-IR) and cell-mediated (Cell-IR) responses in 332 Angus steers.
• Selection of steers with high or low immune responses for miRNA analysis (n=47).
• Analysis of circulating miRNA profiles using linear and logistic regression, and machine learning classification models.

Main Results:

• Circulating miRNA profiles differed between steers with varying immune competence (IC) phenotypes.
• Pre-vaccination miR-150 levels showed a potential association with IC scores and differentiated high/low IC steers.
• A 5-miRNA signature (miR-192, miR-150, miR-2285co, miR-155, let-7a-5p) accurately classified high IC steers (94% accuracy).

Conclusions:

• Circulating miRNAs are associated with immune competence in livestock.
• Specific miRNAs, notably miR-150, may serve as predictive biomarkers for immune response to vaccination.
• These findings highlight the potential of miRNAs for understanding and enhancing vaccine efficacy in cattle.