Immunoglobulins and C3 in the P. brasiliensis granuloma

• Published in: Revista do Instituto de Medicina Tropical de São Paulo
• Main Authors: Lilian M. V. Biagioni, Sonia Orsi, Luiz G. Chamma, Terue Sadatsune, Marcello Frango
• Format: Article in Journal/Newspaper
• Language: English
• Published: Universidade de São Paulo (USP) 1987
• Subjects: Paracoccidioidomicose; Granuloma; Imunoglobulinas; Complemento; Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic
• Online Access: https://doi.org/10.1590/S0036-46651987000200006; https://doaj.org/article/66b448a0f5404192ad15b472d99eada6

The experimental model of paracoccidioidomycosis induced in mice by the intravenous injection of yeast-forms of P. brasiliensis (Bt2 strain; 1 x 10(6) viable fungi/animal) was used to evaluate sequentially 2, 4, 8, 16 and 20 weeks after inoculation: 1. The presence of immunoglobulins and C3 in the pulmonary granuloma-ta, by direct immunofluorescence; 2. The humoral (immunodiffusion test) and the cellular (footpad sweeling test) immune response; 3. The histopathology of lesions. The cell-immune response was positive since week 2, showing a transitory depression at week 16. Specific antibodies were first detected at week 4 and peaked at week 16. At histology, epithelioid granulomas with numerous fungi and polymorphonuclear agreggates were seen. The lungs showed progressive involvement up to week 16, with little decrease at week 20. From week 2 on, there were deposits of IgG and C3 around fungal walls within the granulomas and IgG stained cells among the mononuclear cell peripheral halo. Interstitital immunoglobulins and C3 deposits in the granulomas were not letected. IgG and C3 seen to play an early an important role in. the host defenses against P. brasiliensis by possibly cooperating in the killing of parasites and blocking the antigenic diffusion.