Experimental paracoccidioidomycosis in high and low antibody responder mice of Selection IV-A

• Published in: Medical Mycology Vol. 38; no. 4; pp. 309 - 315
• Main Authors: A. M. V. C. Soares, Rezkallah-Iwasso, M. T., Oliveira, S. L., Peraçoli, M. T. S., Montenegro, M. R. G., Musatti, C. C.
• Format: Journal Article
• Language: English
• Published: UK Informa UK Ltd 2000
• Subjects: Murine Experimental Paracoccidioidomycosis; Adrenal Gland; Histopathology
• ISSN: 1369-3786; 1362-3095; 1460-2709
• DOI: 10.1080/mmy.38.4.309.315

High (H) and low (L) responder mice were selected for their ability to produce antibodies against sheep and human erythrocytes (Selection IV-A). In this selection, the difference in antibody responsiveness between H and L lines (HIV-A and LIV-A mice, respectively) was shown to depend mainly on macrophage function. The more rapid catabolism of antigens by macrophages in L mice has been suggested as the main cause of the low antibody production. Due to this high macrophage activity, L animals have been described as more resistant than H animals to intracellular pathogens. These animals were utilized as an experimental model of paracoccidioidomycosis. HIV-A and LIV-A mice were infected with Paracoccidioides brasilien sis by the intravenous route. As expected, H mice were more susceptible to P. brasiliensis with a shorter survival time and higher levels of specific antibodies when compared to L mice. Contrasting with the survival time, the lungs, spleen and liver from H mice showed typical nodular granulomas containing epithelioid and giant cells and few fungi. On the other hand, in LIV-A mice, the lesions of these organs were characterized by looser granulomas with irregular borders and the presence of a large number of fungi. However, the adrenal gland showed different lesion patterns. In H mice these lesions were extensive and characterized by loose granulomas with numerous fungi, while in LIV-A mice the lesions were small and limited to the cortex. Moreover the HIV-A mice presented higher levels of serum corticosterone when compared to LIV-A ones. The higher susceptibility of H mice could be attributed to the extensive lesions of the adrenal glands. These results suggest the use of the H line from the IV-A Selection as an experimental model for further studies of adrenal involvement in paracoccidioidomycosis.