title: Evaluation of the role of Mycobacterium tuberculosis pili (MTP) as an adhesin, invasin, and cytokine inducer of epithelial cells.
abstract: This study was undertaken in order to assess the involvement of Mycobacterium tuberculosis pili (MTP) as an adhesin, invasin, and cytokine inducer in the M. tuberculosis-epithelial cell interaction. A MTP-deficient strain of M. tuberculosis demonstrated a significant reduction of 69.39% (p=0.047) and 56.20% (p=0.033) in its ability to adhere to and invade A549 pulmonary epithelial cells, respectively, in comparison with the wild-type strain. Complementation of the MTP-deficient mutant restored its adhesion and invasion capacity back to the wild-type levels. Overall, it was found that similar concentrations of IL-1β, IL-4, IL-6, IL-8, G-CSF, IFN-γ, MCP-1, and TNF-α were induced in A549 cells infected with the MTP-proficient and MTP-deficient strains. However, at 48h post-infection, the MTP-deficient mutant induced significantly lower levels of TNF-α than the wild-type strain (p=0.033). Furthermore, at 72h post-infection, the mutant induced significantly higher levels of IL-8 than the wild-type (p=0.005). We conclude that MTP is an adhesin/invasin of epithelial cells and, while playing a role in M. tuberculosis entry, they do not appear to largely influence the epithelial cell cytokine response.
authors.affiliation: Medical Microbiology and Infection Control, University of KwaZulu-Natal, Durban, South Africa.
authors.forename: Saiyur
authors.initials: S
authors.lastname: Ramsugit
authors.affiliation: School of Life Sciences, University of KwaZulu-Natal, Durban, South Africa.
authors.forename: Balakrishna
authors.initials: B
authors.lastname: Pillay
authors.affiliation: Medical Microbiology and Infection Control, University of KwaZulu-Natal, Durban, South Africa. Electronic address: Pillayc@ukzn.ac.za.
authors.forename: Manormoney
authors.initials: M
authors.lastname: Pillay
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism / Q000502:physiology*; D002448:Cell Adhesion / Q000502:physiology*; D016207:Cytokines / Q000276:immunology*; D004847:Epithelial Cells / Q000382:microbiology*; D010861:Fimbriae, Bacterial / Q000502:physiology*; D006801:Humans; D009169:Mycobacterium tuberculosis / Q000276:immunology / Q000502:physiology*
chemical_list: D001426:Bacterial Proteins; D016207:Cytokines
keywords: Adhesin; Curli pili; Invasin; Mycobacterium tuberculosis