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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.)

Early high avidity specific IgG production in experimental hamster visceral leishmaniasis

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de Carvalho, Camila Aparecida [1, 2] ; Ferrao, Thiago Fidelis [1] ; Cavalcante, Fernanda Siqueira [1] ; Novais de Freitas, Flavia Regina [1] ; Meireles, Luciana Regina [1] ; de Andrade Junior, Heitor Franco [1]
Total Authors: 6
[1] Univ Sao Paulo, Inst Med Trop, Fac Med, Sao Paulo - Brazil
[2] Inst Med Trop Sao Paulo, Protozool Lab, Ave Doutor Eneas Carvalho Aguiar 470, BR-05403000 Sao Paulo, SP - Brazil
Total Affiliations: 2
Document type: Journal article
Source: Parasitology Research; v. 119, n. 11 AUG 2020.
Web of Science Citations: 0

Visceral leishmaniasis (VL) byLeishmania (Leishmania) infantumis epidemic in Brazil. Hypergammaglobulinemia appears early in patients with VL and is ineffective. Usually, high-affinity IgG B cells are selected during most infections, a critical step for an effective humoral response. The avidity of IgG antibodies in VL is unexplored due to the absence of temporal parameters in most patients, associated to low clinical significance. Experimental infection models overcome this fact, allowing the monitoring of the disease temporal evolution. In this study, the avidity of IgG antibodies was evaluated in experimental models, in infection in hamsters, and in immunization in rabbits. Specific IgG antibodies were detected by ELISA, using chaotropic solution to determine avidity, as reported for viral infections. The levels of IgG antibodies correlated with the progression of experimental infection in hamsters or antigenic stimulation in immunized rabbits. However, IgG avidity was high early in infected animals, even in early periods (> 80%), while in immunized rabbits, they had early antibodies of low avidity with progressive maturation, similar as other infections. These data suggest that the affinity maturation of the avidity of anti-LeishmaniaIgG antibodies promoted at an early stage, influencing the appropriate interaction between antigens and affecting the disease progression. This fact could be associated to monovalent immune complexes, as reported in human and experimental VL. This scenario may be related to an independent process of immune cell activation by the parasite but absent in antigen preparation used as immunogens. (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: 17/14675-0 - Humoral immune response to haptens of L. (L.) infantum chagasi by detection of specific and natural antibodies in experimental and natural visceral leishmaniasis
Grantee:Camila Aparecida de Carvalho
Support type: Scholarships in Brazil - Post-Doctorate