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Biotechnological and Immunological Platforms Based on PGL-I Carbohydrate-Like Peptide of Mycobacterium leprae for Antibodies Detection Among Leprosy Clinical Forms.

Abstract

Phenolic glycolipid I (PGL-I) is an abundant antigen on the cell wall, commonly used for operational classification of leprosy patients. Our aim was to develop PGL-I mimotopes with similar characteristics and functions of the native antigen. We have used a random peptide () library for selections against the monoclonal antibody anti-PGL-I. After three selection cycles, six peptides were identified. All sequences were interspersed by a spacer generating a chimeric peptide (PGLI-M3) that was artificially synthesized. The highly reactive peptide was submitted to a reverse selection with a single-chain Fv (scFv) antibody fragment combinatorial library. The most reactive scFv was then validated by enzyme-linked immunosorbent assay (ELISA) against both native PGL-I and two derived synthetic (NDO and ND-O-HSA). We have further proved the scFv specificity by detecting bacilli in leprosy lesions through immunohistochemistry. We then described its applicability in ELISA for all clinical forms and household contacts (HC). Afterward, we showed differential binding affinities of PGLI-M3 to sera (anti-PGL-I IgM) from all leprosy clinical forms through surface plasmon resonance (SPR). ELISA IgM detection showed 89.1% sensitivity and 100% specificity, considering all clinical forms. Positivity for anti-PGL-I IgM was twofold higher in both HC and patients with paucibacillary forms in hyperendemic regions than in endemic ones. The SPR immunosensor was able to differentiate clinical forms with 100% accuracy. This is the first time that a PGL-I mimotope has efficiently mimicked the carbohydrate group of the antigen with successful immunoassay applications and may become a substitute for the native antigen.

More information

Type
Journal Article
Author
Lima M
Capparelli F
Oliveira J
Fujimura P
Moraes E
Araujo E
Silva N
Alves-Balvedi R
Brito-Madurro A
Goulart I
Goulart L
Year of Publication
2020
Journal
Frontiers in microbiology
Volume
11
Number of Pages
429
Date Published
01/2020
Language
eng
ISSN Number
1664-302X
DOI
10.3389/fmicb.2020.00429
Alternate Journal
Front Microbiol
PMID
32256479
Publication Language
eng