title: Detection of the tuberculosis antigenic marker mannose-capped lipoarabinomannan in pretreated serum by surface-enhanced Raman scattering.
abstract: The ability to detect tuberculosis (TB) continues to be a global health care priority. This paper describes the development and preliminary assessment of the clinical accuracy of a heterogeneous immunoassay that integrates a serum pretreatment process with readout by surface-enhanced Raman scattering (SERS) for the low-level detection of mannose-capped lipoarabinomannan (ManLAM). ManLAM is a major virulence factor in the infectious pathology of Mycobacterium tuberculosis (Mtb) that has been found in the serum and other body fluids of infected patients. The effectiveness of ManLAM as a TB diagnostic marker, however, remains unproven for reasons not yet well understood. As reported herein, we have found that (1) ManLAM complexes with proteins and possibly other components in serum; (2) these complexes have a strongly detrimental impact on the ability to detect ManLAM using an immunoassay; (3) a simple pretreatment step can disrupt this complexation; and (4) disruption by pretreatment improves detection by 250×. We also describe the results from a preliminary assessment on the utility of serum pretreatment by running immunoassays on archived specimens from 24 TB-positive patients and 10 healthy controls. ManLAM was measurable in 21 of the 24 TB-positive specimens, but not in any of the 10 control specimens. These findings, albeit for a very small specimen set, translate to a clinical sensitivity of 87.5% and a clinical specificity of 100%. Together, these results both provide much needed evidence for the clinical utility of ManLAM as a TB marker, and demonstrate the potential utility of our overall approach to serve as a new strategy for the development of diagnostic tests for this disease.
authors.affiliation: Department of Chemistry, University of Utah, Salt Lake City, UT 84112, USA and Nano Institute of Utah, University of Utah, Salt Lake City, UT 84112, USA. marc.porter@utah.edu.
authors.forename: Alexis C
authors.initials: AC
authors.lastname: Crawford
authors.affiliation: Nano Institute of Utah, University of Utah, Salt Lake City, UT 84112, USA. marc.porter@utah.edu.
authors.forename: Lars B
authors.initials: LB
authors.lastname: Laurentius
authors.affiliation: Department of Chemistry, University of Utah, Salt Lake City, UT 84112, USA.
authors.forename: Timothy S
authors.initials: TS
authors.lastname: Mulvihill
authors.affiliation: Nano Institute of Utah, University of Utah, Salt Lake City, UT 84112, USA. marc.porter@utah.edu.
authors.forename: Jennifer H
authors.initials: JH
authors.lastname: Granger
authors.affiliation: Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO 80523, USA.
authors.forename: John S
authors.initials: JS
authors.lastname: Spencer
authors.affiliation: Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO 80523, USA.
authors.forename: Delphi
authors.initials: D
authors.lastname: Chatterjee
authors.affiliation: Departments of Internal Medicine and Pathology, University of Utah School of Medicine, Salt Lake City, UT 84112, USA.
authors.forename: Kimberly E
authors.initials: KE
authors.lastname: Hanson
authors.affiliation: Department of Chemistry, University of Utah, Salt Lake City, UT 84112, USA and Nano Institute of Utah, University of Utah, Salt Lake City, UT 84112, USA. marc.porter@utah.edu and Department of Chemical Engineering, University of Utah, Salt Lake City, UT 84112, USA and Department of Bioengineering, University of Utah, Salt Lake City, UT 84112, USA and Department of Pathology, University of Utah, Salt Lake City, UT 84112, USA.
authors.forename: Marc D
authors.initials: MD
authors.lastname: Porter
mesh_terms: D053000:Analytic Sample Preparation Methods; D000942:Antigens, Bacterial / Q000097:blood* / Q000378:metabolism*; D015415:Biomarkers / Q000097:blood / Q000378:metabolism; D006801:Humans; D008070:Lipopolysaccharides / Q000097:blood* / Q000378:metabolism*; D008358:Mannose / Q000378:metabolism*; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D013059:Spectrum Analysis, Raman / Q000295:instrumentation / Q000379:methods*
chemical_list: D000942:Antigens, Bacterial; D015415:Biomarkers; D008070:Lipopolysaccharides; C050016:lipoarabinomannan; D008358:Mannose