Alveolar macrophages (AMs) respond to these infections as the first line of defense and trigger the lung's immune response. Knowing the expression dynamics of key immune-related genes in alveolar macrophages against M. haemolytica challenge will help deepen the understanding of disease immunopathogenesis. For this purpose, first time an in vitro obtained from bronchoalveolar lavage (BAL) fluid and treated with three doses (T1: 1800, T2: 2700, T3: 5400 CFU) of M. haemolytica inoculum, while keeping one untreated as a control. Then, total RNA was extracted, and cDNA was synthesized. The real-time quantification data indicated that the expression of IL-1β, IL-6, IL-8, IL-10, and NF-κB genes were significantly changed as compared to control. Our study revealed that the exposure to M. haemolytica stimulates the immune response in the sheep alveolar macrophages in a dose and time-dependent manner.

The alveolar macrophages (AMs) are frontier of defense against foreign materials that initiate immune response in lungs. Knowledge of the expression dynamics of major immune-related genes in the alveolar macrophages in response to lipopolysaccharide (LPS) and lipoteichoic acid (LTA) challenge can help to understand disease mechanism involved in several respiratory diseases. The aim of this study was to investigate the mRNA expression of selected immune-related genes in response to lipopolysaccharide (LPS) and lipoteichoic acid (LTA) challenge in sheep alveolar macrophages in vivo. Results revealed that Romanov lambs exhibited higher mRNA expression of TLR2, TLR4, NF-ĸβ, TNFα, IL-1β, IL-6, IL-8, and IL-10 genes as compared to Akkaraman lambs along with the control of all treatments. Moreover, the expression of TLR2, TLR4, NF-ĸβ, TNFα, IL-1β, IL-6, IL-8, and IL-10 genes was higher in combine treatment of LPS and LTA as compared to separate treatments of LPS and LTA in both breeds. The results showed that the mRNA expression of immune-related genes was significantly increased in the sheep AMs in response to LPS and LTA treatment whereas a synergistic effect was observed in LPS+LTS treatment. Also, breed comparison showed that the native Akkaraman was more resistant to disease compared to exotic Romanov.