title: Filter sterilization of highly infectious samples to prevent false negative analysis of matrix metalloproteinase activity.
abstract: Matrix metalloproteinases (MMPs) are implicated in the immunopathology of numerous infectious diseases. High risk samples such as those generated after infection with Mycobacterium tuberculosis require filter sterilization for safe analysis of MMP concentrations. Here, we report that commercial filter membranes may cause artefacts by binding MMPs. Anopore 0.2 microM membrane filtration reduced MMP-1 concentrations to undetectable levels by zymography and Western blotting. Polypropylene 0.45 microM filtration removed some MMP-1, while Polysulphone, Durapore and Bio-inert 0.2 microM membranes did not remove MMP-1. Anopore filtration also removed all MMP-7 and -9 activity, suggesting that the conserved MMP catalytic domain binds the membrane. This study demonstrates the importance of selecting the appropriate filter in MMP analysis to avoid incorrectly excluding MMP involvement in infection-related immunopathology.
authors.affiliation: Department of Infectious Diseases, Imperial College, Hammersmith Campus, Du Cane Road, London W12 0NN, UK.
authors.forename: P T G
authors.initials: PT
authors.lastname: Elkington
authors.forename: J A
authors.initials: JA
authors.lastname: Green
authors.forename: J S
authors.initials: JS
authors.lastname: Friedland
mesh_terms: D001665:Binding Sites; D015153:Blotting, Western; D001980:Bronchi / Q000201:enzymology / Q000382:microbiology; D002478:Cells, Cultured; D003141:Communicable Diseases / Q000201:enzymology / Q000382:microbiology; D004847:Epithelial Cells / Q000166:cytology / Q000201:enzymology; D005188:False Negative Reactions; D006801:Humans; D066298:In Vitro Techniques; D020781:Matrix Metalloproteinase 1 / Q000032:analysis / Q000302:isolation & purification; D020783:Matrix Metalloproteinase 7 / Q000032:analysis / Q000302:isolation & purification; D020782:Matrix Metalloproteinases / Q000032:analysis* / Q000302:isolation & purification; D008851:Micropore Filters; D009169:Mycobacterium tuberculosis / Q000472:pathogenicity; D013242:Sterilization / Q000379:methods
chemical_list: D020782:Matrix Metalloproteinases; D020783:Matrix Metalloproteinase 7; D020781:Matrix Metalloproteinase 1