maleic-acid and Tuberculosis

Membrane proteins of Mycobacterium tuberculosis (Mtb) can be targeted for the development of therapeutic and prophylactic interventions against tuberculosis. We have utilized the unique membrane-solubilising properties of the styrene maleic acid copolymer (SMA) to prepare and characterise 'styrene maleic acid lipid particles' from the native membrane of Mtb (MtM-SMALPs). When resolved by SDS-PAGE and visualised with coomassie blue, the molecular weights of Mtb membrane (MtM) proteins solubilised by SMA were mostly in the range of 40-70 kDa. When visualised by transmission electron microscopy, MtM-SMALPs appeared as nanoparticles of discrete shapes and sizes. The discoid nanoparticles exhibited a range of diameters of ~10-90 nm, with largest portion (~61%) ranging from 20-40 nm. MtM proteins of a molecular weight-range overlapping with that of MtM-SMALPs were also amenable to chemical cross-linking, revealing protein complex formation. Characterisation using monoclonal antibodies against seven MtM-associated antigens confirmed the incorporation of the inner membrane protein PRA, membrane-associated proteins PstS1, LpqH and Ag85, and the lipoglycan LAM into MtM-SMALPs. Conversely, the peripheral membrane proteins Acr and PspA were nearly completely excluded. Furthermore, although MtM showed an abundance of Con A-binding glycoproteins, MtM-SMALPs appeared devoid of these species. Immune responses of healthcare workers harbouring 'latent TB infection' provided additional insights. While MtM-SMALPs and MtM induced comparable levels of the cytokine IFN-γ, only MtM-SMALPs could induce the production of TNF-α. Antibodies present in the donor sera showed significantly higher binding to MtM than to MtM-SMALPs. These results have implications for the development of MtM-based immunoprophylaxis against tuberculosis.

Topics: Cell Membrane; Humans; Lipid Bilayers; Lipids; Maleates; Membrane Proteins; Mycobacterium tuberculosis; Polystyrenes; Styrene; Tuberculosis

Topics: Animals; Antitubercular Agents; Drug Therapy, Combination; Guinea Pigs; In Vitro Techniques; Levamisole; Maleates; Mice; Mice, Inbred C57BL; Nucleic Acids; Succinates; Succinic Acid; T-Lymphocytes; Tuberculosis

Topics: Animals; Antitubercular Agents; Drug Therapy, Combination; Guinea Pigs; Immunity, Cellular; Maleates; Nucleic Acids; Succinates; Succinic Acid; T-Lymphocytes; Tuberculosis