[PubMed] [Google Scholar] 30

[PubMed] [Google Scholar] 30. individual systemic mycosis due to the dimorphic fungus infections thermally, whereas high degrees of particular antibodies and polyclonal activation of B cells are from the most severe types of the condition (2, 13, 34, 40). Utilizing a murine style of intraperitoneally (we.p.) induced PCM, Calich et al. (9) demonstrated that there have been significant distinctions in susceptibility among inbred strains: A/Sn mice were found to be the most resistant, while B10.A animals were the most susceptible to infection. More recently, we developed a pulmonary PCM model employing the same inbred mouse strains but using the intratracheal (i.t.) route (11). It was observed that A/Sn mice developed a chronic benign, pulmonary-restricted PCM whereas B10.A mice developed a progressive disseminated disease. The results obtained suggested that resistance to PCM was associated with T-cell, macrophage, and B-cell activities that are known to be mediated by gamma interferon (IFN-). It has been well documented that IFN- plays a pivotal role in host resistance against various pathogens through augmentation of the killing activity Mouse Monoclonal to Goat IgG of macrophages (7, 15, Acetazolamide 26, 30). IFN–activated macrophages presented an enhanced killing activity against conidia and yeast cells (6, 12). Mody et al. (30) demonstrated IFN–induced improvement of cryptococcocidal activity of rat alveolar macrophages. In Acetazolamide addition, Salkowski and Balish (39) showed enhancement of natural killer (NK) cell activity by IFN- during cryptococcal infection and impaired clearance of the fungus from the spleens, lungs, and livers of mice treated with anti-IFN- monoclonal antibody (MAb). The availability of these reagents has facilitated many studies aimed at elucidating IFN–mediated immune mechanisms at the molecular Acetazolamide level and at defining its in vivo physiologic role. The purpose of this work was to identify type 1 (IFN- and interleukin-2 [IL-2]) and type 2 (IL-4, IL5, and IL-10) cytokines produced at the site of infection and to verify the effects of anti-IFN- MAbs as an in vivo treatment in the murine pulmonary model of PCM. We studied the pulmonary infection, extrapulmonary dissemination, specific delayed-type hypersensitivity (DTH) reactions, and specific humoral responses in three groups of animals (untreated, treated with normal immunoglobulin G [IgG], and treated with anti-IFN- MAbs) of each mouse strain (A/Sn and B10.A) at two periods post-i.t. infection (weeks 4 and 8). We demonstrated a mixed pattern of pulmonary cytokine secretion in both mouse strains, but the levels of IFN-, IL-4, IL-5, and IL-10 were higher in the lungs of susceptible animals. We also verified that irrespective of the mouse strain, IFN- plays an important role in resistance to infection, through its enhancement of the clearance of fungal cells and of cell-mediated immune responses and its regulatory effects on specific humoral immune responses. Furthermore, the proinflammatory activity of this cytokine appears to be crucial to the induction of circumscribed lesions in the lungs. MATERIALS AND METHODS Fungus. 18, an isolate which is highly virulent (25), was used throughout this study. To ensure the maintenance of its virulence, the isolate was used after three serial animal passages (23). 18 yeast cells were then maintained by weekly subcultivation in semisolid Fava Nettos culture medium (16) at 35C and used at the 7th day in culture. The fungal cells were washed in phosphate-buffered saline (PBS; pH 7.2) and counted in a hemocytometer, and the concentration was adjusted to 20 106 fungal cells ml?1. Viability of fungal suspensions, determined by Janus green B vital dye (Merck, Darmstadt, Germany) (5), was always higher than 80%. Animals. Unless otherwise stated, groups of 8 to 10 male mice (9 to 11 weeks old) from the susceptible (B10.A) and resistant (A/Sn) strains were used for each period of infection. BALB/c mice were used for the expansion of the anti-IFN- hybridoma. All animals were bred at the University of S?o Paulo animal facilities and provided with acidified water and sterilized food and bedding. Surgical i.t. inoculation. Mice were anesthetized by the i.p. route with a 0.4% solution of 2-(2,6-xylidine) 5,6-dihydro-4 H-1,3-thiasine hydrochloride (10 ml/kg of body weight; Rompun;.