Profiling Antibodies to Mycobacterium tuberculosis (M. tb.) by Multiplex Microbead Suspension Arrays for Serodiagnosis of TB

Center for Comparative Medicine, Dept. of Pathology and Laboratory Medicine, California National Primate Research Center, School of Medicine, University of California, Davis, CA 95616, Division of Pulmonary and Critical Care Medicine, Oregon Health and Sciences University, Portland, OR 97239, Public Health Res. Inst., Newark, NJ 07103, Dept. of Molecular Genetics and Biochemistry, University of Pittsburg, PA 15261, University of California, Irvine, CA 91679

	Abstract

Tuberculosis (TB) is a serious global disease. Fatality rate attributed to TB is among the highest of infectious diseases, with approximately 2 million deaths occurring per year worldwide. Identification of individuals infected with Mycobacterium tuberculosis (M. tb.), and screening of their immediate contacts, is crucial for controlling the spread of TB. Current methods for detection of M. tb. infection are not efficient, in particular for testing large numbers of samples. We report a novel and efficient multiplex microbead immunoassay (MMIA), based on Luminex® technology, for profiling antibodies to M.tb. Microbead sets identifiable by unique fluorescence were individually coated with each of several M.tb. antigens and tested in multiplex format for antibody detection in the experimental nonhuman primate model of TB. Certain M. tb. antigens e.g., ESAT-6, CFP-10 and HspX were included to enhance specificity of MMIA because these antigens are absent in nontuberculus Mycobacteria and the vaccine strain BCG (bacillus Clamette-Guerin). MMIA enabled simultaneous detection of multiple M.tb. plasma antibodies in several cohorts of macaques representing different stages of infection and/or disease. Antibody profiles were defined in early and latent/chronic infection. These proof-of-concept findings demonstrate potential clinical use of MMIA. In addition, MMIA serodetection system has potential for mining M.tb. open-reading-frames (about 4,000) to discover novel target proteins for the development of more comprehensive TB serodiagnostic tests.