title: Deciphering the proteome of the in vivo diagnostic reagent "purified protein derivative" from Mycobacterium tuberculosis.
abstract: Purified protein derivative (PPD) has served as a safe and effective diagnostic reagent for 60 years and is the only broadly available material to diagnose latent tuberculosis infections. This reagent is also used as a standard control for a number of in vitro immunological assays. Nevertheless, the molecular composition and specific products that contribute to the extraordinary immunological reactivity of PPD are poorly defined. Here, a proteomic approach was applied to elucidate the gene products in the U.S. Food and Drug Administration (FDA) standard PPD-S2. Many known Mycobacterium tuberculosis T-cell antigens were detected. Of significance, four heat shock proteins (HSPs) (GroES, GroEL2, HspX, and DnaK) dominated the composition of PPD. The chaperone activities and capacity of these proteins to influence immunological responses may explain the exquisite solubility and immunological potency of PPD. Spectral counting analysis of three separate PPD reagents revealed significant quantitative variances. Gross delayed-type hypersensitivity (DTH) responses in M. tuberculosis infected guinea pigs were comparable among these PPD preparations; however, detailed histopathology of the DTH lesions exposed unique differences, which may be explained by the variability observed in the presence and abundance of early secretory system (Esx) proteins. Variability in PPD reagents may explain differences in DTH responses reported among populations.
authors.affiliation: Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, USA.
authors.forename: Yun Sang
authors.initials: YS
authors.lastname: Cho
authors.forename: Karen M
authors.initials: KM
authors.lastname: Dobos
authors.forename: Jessica
authors.initials: J
authors.lastname: Prenni
authors.forename: Hongliang
authors.initials: H
authors.lastname: Yang
authors.forename: Ann
authors.initials: A
authors.lastname: Hess
authors.forename: Ida
authors.initials: I
authors.lastname: Rosenkrands
authors.forename: Peter
authors.initials: P
authors.lastname: Andersen
authors.forename: Sung Weon
authors.initials: SW
authors.lastname: Ryoo
authors.forename: Gill-Han
authors.initials: GH
authors.lastname: Bai
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Brennan
authors.forename: Angelo
authors.initials: A
authors.lastname: Izzo
authors.forename: Helle
authors.initials: H
authors.lastname: Bielefeldt-Ohmann
authors.forename: John T
authors.initials: JT
authors.lastname: Belisle
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial / Q000032:analysis / Q000737:chemistry* / Q000145:classification / Q000276:immunology; D001426:Bacterial Proteins / Q000032:analysis / Q000737:chemistry* / Q000145:classification / Q000276:immunology; D006168:Guinea Pigs; D009169:Mycobacterium tuberculosis / Q000737:chemistry* / Q000276:immunology; D020543:Proteome / Q000032:analysis / Q000737:chemistry*; D014373:Tuberculin / Q000032:analysis / Q000737:chemistry* / Q000276:immunology; D014376:Tuberculosis / Q000276:immunology / Q000382:microbiology
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D020543:Proteome; D014373:Tuberculin