In vitro and in situ activation of the complement system by the fungus Lacazia loboi Ativação in vitro e in situ do sistema complemento pelo fungo Lacazia loboi

• Published in: Revista do Instituto de Medicina Tropical de São Paulo
• Main Authors: Fátima Regina Vilani-Moreno, Érika Mozer, Ana Márcia Guedes de Sene, Margarete de Oliveira Ferasçoli, Tânia Cristina Pereira, Márcia Garcia Miras, Gláucia Heloísa de Paula Souza, Andréa de Faria Fernandes Belone
• Format: Article in Journal/Newspaper
• Language: English
• Published: Universidade de São Paulo (USP) 2007
• Subjects: Complement system; Lacazia loboi; Jorge Lobo's disease; Immunofluorescence; Skin lesions; Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic
• Online Access: https://doi.org/10.1590/S0036-46652007000200006; https://doaj.org/article/37578694187f4b9998d4ea5af22036af

Since there are no studies evaluating the participation of the complement system (CS) in Jorge Lobo's disease and its activity on the fungus Lacazia loboi, we carried out the present investigation. Fungal cells with a viability index of 48% were obtained from the footpads of BALB/c mice and incubated with a pool of inactivated serum from patients with the mycosis or with sterile saline for 30 min at 37 ºC. Next, the tubes were incubated for 2 h with a pool of noninactivated AB+ serum, inactivated serum, serum diluted in EGTA-MgCl2, and serum diluted in EDTA. The viability of L. loboi was evaluated and the fungal suspension was cytocentrifuged. The slides were submitted to immunofluorescence staining using human anti-C3 antibody. The results revealed that 98% of the fungi activated the CS by the alternative pathway and no significant difference in L. loboi viability was observed after CS activation. In parallel, frozen histological sections from 11 patients were analyzed regarding the presence of C3 and IgG by immunofluorescence staining. C3 and IgG deposits were observed in the fungal wall of 100% and 91% of the lesions evaluated, respectively. The results suggest that the CS and immunoglobulins may contribute to the defense mechanisms of the host against L. loboi. Considerando que não existe nenhum estudo avaliando a participação do sistema complemento (SC) na doença de Jorge Lobo e sua atividade sobre o fungo Lacazia loboi, realizamos o presente trabalho. Os fungos foram obtidos dos coxins plantares de camundongos BALB/c com índice de viabilidade de 48% e, em seguida, foram incubados com pool de soro inativado de pacientes ou com solução salina estéril (SSE) por 30 min, a 37 ºC. Os tubos foram incubados, por 2 h, com pool de soro AB+ sem inativar, inativado, diluído em EGTA-MgCl2 e EDTA. A viabilidade do L. loboi foi avaliada e a suspensão fúngica foi citocentrifugada. As lâminas foram submetidas à técnica de imunofluorescência empregando o anticorpo anti-C3 humano. Os resultados revelaram que 98% dos fungos ...