Fetuin a Contributes in Anti-chlamydial Immunity in Pulmonary Chlamydia Muridarum Infections

Fetuin A, also known as alpha-2-HS-glycoprotein (AHSG) encoded by AHSG gene is a negative acute phase protein which can inhibit the synthesis of pro inflammatory cytokines in order to prevent excessive inflammation, stimulate phagocytosis and endocytosis, counter regulate macrophage activation in turns to restrain innate immune response. Alternatively, pro inflammatory cytokines can play roles in reducing the circulating level of AHSG to call forth downstream inflammation. Its role in the control of pulmonary chlamydia muridarum (Cm) infection is yet to be studied. Hence this study was conducted using AHSG knock out murine model to investigate the influence of this molecule on host pathological response against C. mur lung infection. It was found that IFN gamma as low as 20-30 pg/ml could inhibit its expression in the lung tissue lysate over 50% of its original concentration at early days of infection in the wild type C57BL/6 mice. Also, AHSG knock out infected mice had a tendency of faster recovery rate over that of WT infected mice in terms of weight loss and bacterial burden, on average higher weight change index over the duration of infection and less IFN gamma production post infection in both the lung and spleen. We also identified chemokines, cytokines and other associated molecules along with probable transcriptomic polar effect introduced followed by the deletion of AHSG that could be further investigated in order to better understand the mechanism of action of AHSG and draw a conclusive ending on its importance in host immunity.