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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

High levels of serum glycans monovalent IgG immune complexes detected by dissociative ELISA in experimental visceral leishmaniasis

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de Carvalho, Camila Aparecida [1] ; Ferrao, Thiago Fidelis [1] ; Novais de Freitas, Flavia Regina [1] ; de Andrade Junior, Heitor Franco [1]
Total Authors: 4
[1] Univ Sao Paulo, Lab Protozool, Inst Med Trop, Sao Paulo - Brazil
Total Affiliations: 1
Document type: Journal article
Source: IMMUNOLOGY; v. 158, n. 4, p. 314-321, DEC 2019.
Web of Science Citations: 0

Visceral leishmaniasis (VL) is epidemic in Brazil with an increasing incidence of human cases and canine reservoirs, with host hypergammaglobulinemia. Conventional enzyme-linked immunosorbent assay (cELISA) based on several parasitic antigens is the main method for diagnosis and indication of treatment. Dissociative ELISA (dELISA) uses acidic treatment to free immunoglobulin G (IgG) from immune complexes, and its use revealed a significant positive fraction of suspected cases with negative serology. Looking for small molecules or haptens that block IgG antibodies, we purified by molecular exclusion chromatography, 1000-3000 MW molecules from promastigote soluble extract, mostly oligosaccharides comprising 6-13 sugar residues using MALDI-TOF analysis. Glycan-BSA complex (GBC) was constructed by conjugating promastigote glycans to BSA molecules, allowing their use in the solid support in cELISA or dELISA. Sera from experimentally infected hamsters showed higher levels of blocked monomeric IgG during infection, mostly against GBC, which was also present in lower concentrations in the promastigote soluble extract dELISA. Those data show that most of the specific monomeric IgG in serum are blocked by haptens composed by glycans produced by the parasite, better detected in the high dilution of sera in the dELISA assays. dELISA is a useful technique for detecting blocked monomeric antibodies that could have difficult clearance from blood, which could result in hypergammaglobulinemia. (AU)

FAPESP's process: 17/26558-9 - Haptens in visceral leishmaniasis. Development of solid phase assays for diagnosis and its immunology in experimental models.
Grantee:Heitor Franco de Andrade Junior
Support type: Regular Research Grants
FAPESP's process: 13/50218-2 - CEPEMA - Cooperative Center of Environmental Engineering
Grantee:Claudio Augusto Oller do Nascimento
Support type: Research Projects - Thematic Grants