Comparative gene expression analysis of toll-like receptors in resistant and susceptible buffalo breeds challenged with mastitis pathogens

Abstract

Leading immunologists increasingly recognise that breed-level variation in innate immune receptor expression may explain why certain buffalo populations resist mastitis while others succumb under identical management conditions [1]. This research compared toll-like receptor (TLR) gene expression in mammary tissue from Murrah (resistant phenotype) and Nili-Ravi (susceptible phenotype) buffalo breeds following experimental challenge with Staphylococcus aureus and Escherichia coli. Mammary biopsies from 24 buffaloes (12 per breed) were analysed by RT-qPCR at 6, 12, and 24 hours post-challenge. Murrah buffaloes showed significantly higher expression of TLR2 (4.8-fold vs 1.9-fold, p < 0.001), TLR4 (6.2 vs 2.4-fold, p < 0.001), TLR9 (3.7 vs 1.5-fold, p < 0.01), and the adaptor molecule MyD88 (5.4 vs 2.1-fold, p < 0.001) at 12 hours. Somatic cell counts (SCC) at 24 hours were lower in Murrah (486 × 10³/mL) than Nili-Ravi (1,240 × 10³/mL, p < 0.001). These findings suggest that enhanced TLR-mediated innate immune activation contributes to the mastitis resistance phenotype observed in Murrah buffaloes.