Experimental coccidioidomycosis in the immunosuppressed rat

Abstract

C. immitis inoculated rats are known to develop infection restricted to lung whereas cyclophosphamide (CY) treatment leads to widespread dissemination with considerable mortality. In this study, an attempt was made to elucidate the mechanisms involved in such behaviour. With this aim, spleen cells were transferred from infected CY-treated to infected untreated rats, achieving significant specific inhibition in footpad swelling to coccidioidin in recipients, attributable to a suppressor T cell subpopulation induced by greater fungal antigen concentration arising from widespread C. immitis dissemination in immunosuppressed animals. NK activity proved similar regardless of CY treatment. Lastly, chronically infected rats presented increased colony forming units count after several weekly doses of CY, as happens in immunosuppressed patients harbouring a previous infection.

Experimental coccidioidomycosis in hamsters. Disease kinetics and death curve in relation to infective dose

“…Disseminated coccidioidomycosis is a serious, chronic granulomatous disease whose incidence is increasing in endemic areas, particularly in the United States [ 5, 6]. Different species of animals and immunological conditions have been used to develop experimental models to study the physiopathological mechanisms of the disease [ 14–16, 25]. The early experiments conducted by Alejandro Posadas [ 26] showed, using a variety of warm‐ and cold‐blooded animals inoculated with C. immitis by different means, that cold‐blooded animals were refractory to infection.…”

“…The early experiments conducted by Alejandro Posadas [ 26] showed, using a variety of warm‐ and cold‐blooded animals inoculated with C. immitis by different means, that cold‐blooded animals were refractory to infection. Other studies have shown that experimental inoculation of the mycelial form of C. immitis leads to disseminated disease with variable mortality, which is dependent upon (a) the route of infection [ 1, 14]; (b) immunological status of the animal [ 25, 28, 29]; (c) the strain of C. immitis [ 30]; (d) animal species [ 15, 16, 22].…”