HOUSE DUST MITES, BACTERIA AND ASTHMA: THE POTENTIAL MODULATORY ROLE OF GRAM-POSITIVE BACTERIAL PAMPS [ 2007 - 2009 ]

Research Grant

Researchers: Prof Geoffrey Stewart (Principal investigator) ,  Leslie Mathaba

Brief description Asthma continues to be a socio-economically important disease with an increasing prevalence. In this regard, allergy to the house dust mite appears to predispose children to the development of the disease although the reasons are unclear. Recently, we discovered and characterised a bacteriolytic enzyme which had previously only been described in pathogenic bacteria, particularly Mycobacteria. In an attempt to determine the origin of the lytic enzyme, we demonstrated that mites also contained a diverse array of Gram-positive bacteria in contrast to Gram-negative bacteria within their guts. Interestingly, the same spectrum of bacterial species were found in carpet and mattress dust from children with asthma. A variety of data suggest exposure to products from Gram-positive organisms may enhance allergic diseases including asthma. In contrast, exposure to products from Gram-negative bacteria is thought to be protective for asthma development. The reasons for the association between Gram-positive bacteria and asthma have not been explored in detail but one potential mechanism that will be explored in this application is the the role of the cell wall constituents which demarcate Gram-positive organisms from Gram-negative organisms as well as sectreted products. The underlying mechanisms involved are likely to reflect a differential ability of the two types of organisms to stimulate the release of divergent immunomodulatory cytokines from cells known to play a role in asthma such as epithelial cells, fibroblasts, T cells and dendritic cells. Data from such studies are likely to greatly increase our understanding of the development of asthma and, therefore, contibute to the development of new treatment modalities with consequent benefit to the community.

Funding Amount $AUD 518,210.05

Funding Scheme NHMRC Project Grants

Notes Standard Project Grant