<i>Mycobacterium vaccae</i> Immunization to Pregnant BALB/c Mice Ameliorated Lung Histopathology and Bone Marrow Eosinophila in Ovalbumin Sensitized Offsprings

Abstract

Context: One of the treatment strategies for atopic diseases is to skew immune response away from Th2 dominance by using Mycobacterial strains. Objective: We wanted to find out whether M. vaccae administration to pregnant mice had any preventive effect on the offsprings in the development of a murine asthma model. Materials and Methods: Pregnant BALB/c mice were divided into two groups; first group received heat-killed M. vaccae subcutaneously on 12th day of pregnancy and the latter group received PBS. After delivery, newborn mice of each group were further divided into two subgroups as M. vaccae/Ovalbumin (OVA), M. vaccae/control, PBS/OVA and PBS/ control. To establish experimental murine asthma model, mice were intraperitoneally sensitized and challenged intratracheally with Ovalbumin. We analysed airway histopathology, bone marrow eosinophil progenitors and splenic cell cytokine profiles of the offsprings. Results: Comparison of offsprings in M. vaccae/OVA group were not different than PBS controls with respect to thicknesses of airway epithelium, basement membrane, subepithelial smooth muscles and number of hyperplasic goblet cells as well as bronchial associated lymphoid tissue density and eosinophil progenitors in the bone marrow. Comparison of M. vaccae/OVA group to asthma model revealed significant differences and lower levels of OVA-induced IL-5. Conclusions: We propose that immunization of pregnant BALB/c with M. vaccae could prevent histopathological alterations in the airways related to the asthma model and down-regulates IL-5 secretion from splenocytes of offsprings.