Paracoccidioidomycosis: an update

Human serum antibody reactivity towards Paracoccidioides brasiliensis antigens treated with sodium metaperiodate

In this study, we evaluated the profile of anti-Paracoccidioides brasiliensis immunoglobulin isotypes in serum from patients with the acute and chronic forms of paracoccidioidomycosis, using the whole Paracoccidioides brasiliensis antigen and the antigen treated with sodium metaperiodate. All the immunoglobulin isotypes present in the serum from patients with the acute and chronic forms of paracoccidioidomycosis presented higher reactivity towards the whole antigen than to the antigen treated with metaperiodate (P < 0.05). The reactivity of IgG and IgM to the antigen treated with metaperiodate was greater in serum from patients with the acute form of the disease (P < 0.05), while IgA was more reactive in serum from patients with the chronic form (P < 0.05). There was greater reactivity of IgG1 and IgG2 to the whole antigen and the antigen treated with metaperiodate in the serum from patients with paracoccidioidomycosis than there was in serum from patients with other parasitic infections (P < 0.05). Furthermore, IgG1 from patients with the acute form recognized the 19kDa, 27kDa and 31kDa antigens in the western blot test. Thus, the results suggest that modifications to the epitopes of Paracoccidioides brasiliensis antigens may help to improve the immunodiagnosis of paracoccidioidomycosis.

Vaccination with heat shock protein 60 induces a protective immune response against experimental Paracoccidioides brasiliensis pulmonary infection

Paracoccidioides brasiliensis causes a chronic granulomatous mycosis prevalent in Latin America. The successful resolution of infection with this fungus is dependent on the activation of cellular immunity. We previously identified heat shock protein 60 (HSP60) as a target of the humoral response in paracoccidioidomycosis. Herein we expressed the gene encoding HSP60 in Escherichia coli and analyzed the immunological activity of this recombinant antigen. The immunization of BALB/c mice with recombinant protein emulsified in adjuvant stimulated a cellular immune response. Splenocytes from immunized mice proliferated in response to antigen and released interleukin-12 and gamma interferon (IFN-gamma). Vaccination with HSP60 reduced the fungal burden in mice given 10(6) or 10(7) yeasts and protected mice from a lethal challenge. The efficacy of the vaccination was blunted by the neutralization of IFN-gamma. CD4(+) cells were necessary for the efficacy of the vaccination in both the afferent and efferent phases. Thus, we have demonstrated that this immunodominant antigen is a candidate for the development of a vaccine against this fungus.

Therapeutic administration of KM+ lectin protects mice against Paracoccidioides brasiliensis infection via interleukin-12 production in a toll-like receptor 2-dependent mechanism

KM(+) is a mannose-binding lectin from Artocarpus integrifolia that induces interleukin (IL)-12 production by macrophages and protective T helper 1 immune response against Leishmania major infection. In this study, we performed experiments to evaluate the therapeutic activity of jackfruit KM(+) (jfKM(+)) and its recombinant counterpart (rKM(+)) in experimental paracoccidioidomycosis. To this end, jfKM(+) or rKM(+) was administered to BALB/c mice 10 days after infection with Paracoccidiodes brasiliensis. Thirty days postinfection, lungs from the KM(+)-treated mice contained significantly fewer colony-forming units and little to no organized granulomas compared to the controls. In addition, lung homogenates from the KM(+)-treated mice presented higher levels of nitric oxide, IL-12, interferon-gamma, and tumor necrosis factor-alpha, whereas higher levels of IL-4 and IL-10 were detected in the control group. With mice deficient in IL-12, Toll-like receptor (TLR) 2, TLR4, or TLR adaptor molecule MyD88, we demonstrated that KM(+) led to protection against P. brasiliensis infection through IL-12 production, which was dependent on TLR2. These results demonstrated a beneficial effect of KM(+) on the severity of P. brasiliensis infection and may expand its potential use as a novel immunotherapeutic molecule.

Glycoconjugates and polysaccharides of fungal cell wall and activation of immune system

Glycoproteins, glycosphingolipids and polysaccharides exposed at the most external layers of the wall are involved in several types of interactions of fungal cells with the exocellular environment. These molecules are fundamental building blocks of organisms, contributing to the structure, integrity, cell growth, differentiation and signaling. Several of them are immunologically active compounds with potential as regulators of pathogenesis and the immune response of the host. Some of these structures can be specifically recognized by antibodies from patients’ sera, suggesting that they can be also useful in the diagnosis of fungal infections.

[Paracoccidioidomycosis in a four-year-old boy]

A paracoccidioidomycosis case in a four-year old boy, with fever, lymphadenopathy and hepatosplenomegaly is presented. The diagnosis was confirmed by serology and lymph node biopsy. The patient was treated with amphotericin B. After 48 hours, clinical improvement and considerable adenopathies remission were observed.

T helper 1-inducing adjuvant protects against experimental paracoccidioidomycosis

Immunostimulatory therapy is a promising approach to improving the treatment of systemic fungal infections such as paracoccidioidomycosis (PCM), whose drug therapy is usually prolonged and associated with toxic side effects and relapses. The current study was undertaken to determine if the injection of a T helper (Th) 1–stimulating adjuvant in P. brasiliensis–infected mice could have a beneficial effect on the course of experimental PCM. For this purpose, mice were infected and treated with complete Freund's adjuvant (CFA), a well-established Th1 experimental inductor, or incomplete Freund's adjuvant (IFA - control group) on day 20 postinfection. Four weeks after treatment, the CFA-treated mice presented a mild infection in the lungs characterized by absence of epithelioid cell granulomas and yeast cells, whereas the control mice presented multiple sites of focal epithelioid granulomas with lymphomonocytic halos circumscribing a high number of viable and nonviable yeast cells. In addition, CFA administration induced a 2.4 log reduction (>99%) in the fungal burden when compared to the control group, and led to an improvement of immune response, reversing the immunosuppression observed in the control group. The immunotherapy with Th1-inducing adjuvant, approved to be used in humans, might be a valuable tool in the treatment of PCM and potentially useful to improve the clinical cure rate in humans.

P. brasiliensis is a thermally dimorphic human pathogenic fungus that causes paracoccidioidomycosis (PCM), the most prevalent human systemic mycosis in Latin America, whose drug therapy is usually prolonged and associated with toxic side effects and relapses. Although immunostimulatory therapy is a promising approach to improving the treatment of fungal infections as PCM, few studies have been reported. In the current study, we verified that a single-dose administration of an adjuvant that induces T helper (Th) 1 immune response (complete Freund's adjuvant [CFA]) in P. brasiliensis–infected mice was sufficient to break the lack of immune response to the fungus observed in infected mice. Four weeks after treatment, the CFA-treated mice presented a mild infection in the lungs characterized by preserved lung structure and small fungal burden, whereas control mice that had been treated with incomplete Freund's adjuvant presented many granulomatous lesions and high fungal burden. The immunotherapy with Th1-inducing adjuvant might be a valuable tool in the treatment of PCM and potentially useful for faster and efficient cure of PCM in humans.

Ultrastructural changes in Paracoccidioides brasiliensis yeast cells attenuated by gamma irradiation

Paracoccidioides brasiliensis is a thermally dimorphic fungus agent of paracoccidioidomycosis, a deep-seated systemic infection of humans with high prevalence in Latin America. Until now no vaccine has been reported. Ionizing radiation can be used to attenuate pathogens for vaccine development and we have successfully attenuated yeast cells of P. brasiliensis by gamma irradiation. The aim of the present study was to examine at ultrastructural level the effects of gamma irradiation attenuation on the morphology of P. brasiliensis yeast cells. Paracoccidioides brasiliensis (strain Pb-18) cultures were irradiated with a dose of 6.5 kGy. The irradiated cells were examined by scanning and also transmission electron microscopy. When examined 2 h after the irradiation by scanning electron microscopy, the 6.5 kGy irradiated cells presented deep folds or were collapsed. These lesions were reversible since when examined 48 h after irradiation the yeast had recovered the usual morphology. The transmission electron microscopy showed that the irradiated cells plasma membrane and cell wall were intact and preserved. Remarkable changes were found in the nucleus that was frequently in a very electrondense form. An extensive DNA fragmentation was produced by the gamma irradiation treatment.

Fungal Infections

The incidence of invasive fungal infections has increased dramatically over the past two decades, mostly due to an increase in the number of immunocompromised patients.1–4 Patients who undergo chemotherapy for a variety of diseases, patients with organ transplants, and patients with the acquired immune deficiency syndrome have contributed most to the increase in fungal infections.5 The actual incidence of invasive fungal infections in transplant patients ranges from 15% to 25% in bone marrow transplant recipients to 5% to 42% in solid organ transplant recipients.6,7 The most frequently encountered are Aspergillus species, followed by Cryptococcus and Candida species. Fungal infections are also associated with a higher mortality than either bacterial or viral infections in these patient populations. This is because of the limited number of available therapies, dose-limiting toxicities of the antifungal drugs, fewer symptoms due to lack of inflammatory response, and the lack of sensitive tests to aid in the diagnosis of invasive fungal infections.1 A study of patients with fungal infections admitted to a university-affiliated hospital indicated that community-acquired infections are becoming a serious problem; 67% of the 140 patients had community-acquired fungal pneumonia.8

Genotyping ofParacoccidioides brasiliensisdirectly from paraffin embedded tissue

Based on polymorphisms of the gp43 precursor gene, genotyping of Paracoccidioides brasiliensis was achieved in 6 out of 10 paraffin-embedded tissue samples by modifying a nested PCR procedure used in the diagnosis of the fungal infection. Nine of the samples originated in Brazil. Three sequences were identical to a previously published consensus sequence identifying the P. brasiliensis isolates as members of the formerly named species 1. In contrast, two sequences revealed substitutions identical to isolates of the phylogenetic species 2. Applying the method to a lung biopsy from a proven case of paracoccidioidomycosis diagnosed in Austria, the gp43 sequence revealed substitutions so far only described in five strains originating from Venezuela. Combining travel history and result of this new method, the most probable country of origin of the infections could be identified. Since endemic mycosis are often diagnosed by histopathology only, our method could help to extend epidemiological studies of paracoccidioidomycosis.

Animal models: an important tool in mycology

Animal models of fungal infections are, and will remain, a key tool in the advancement of the medical mycology. Many different types of animal models of fungal infection have been developed, with murine models the most frequently used, for studies of pathogenesis, virulence, immunology, diagnosis, and therapy. The ability to control numerous variables in performing the model allows us to mimic human disease states and quantitatively monitor the course of the disease. However, no single model can answer all questions and different animal species or different routes of infection can show somewhat different results. Thus, the choice of which animal model to use must be made carefully, addressing issues of the type of human disease to mimic, the parameters to follow and collection of the appropriate data to answer those questions being asked. This review addresses a variety of uses for animal models in medical mycology. It focuses on the most clinically important diseases affecting humans and cites various examples of the different types of studies that have been performed. Overall, animal models of fungal infection will continue to be valuable tools in addressing questions concerning fungal infections and contribute to our deeper understanding of how these infections occur, progress and can be controlled and eliminated.

Transcriptional profile of ras1 and ras2 and the potential role of farnesylation in the dimorphism of the human pathogen Paracoccidioides brasiliensis

Paracoccidioides brasiliensis is a thermo-dimorphic fungus that causes a human systemic mycosis with high incidence in Latin America. Owing to their participation in the control of pathogen morphogenesis, differentiation and virulence, it was decided to characterize ras genes in P. brasiliensis. ras1 and ras2 were identified to be coding for two different proteins with high identity. The ras transcriptional pattern was investigated by reverse transcription PCR (RT-PCR) during mycelium-to-yeast (M-->Y) transition, heat shock at 42 degrees C and after internalization of yeast cells by murine macrophages. Both genes were downregulated inside macrophages and ras1, at 42 degrees C. In contrast, ras genes did not show any transcriptional variation during the M-->Y transition. The fact that Ras proteins are attached to the membrane via farnesylation prompted the use of a farnesyltransferase inhibitor to investigate the importance of this process for vegetative growth and dimorphic transition. Farnesylation blockage interfered with the vegetative growth of yeast cells and stimulated germinative tube production even at 37 degrees C. During Y-->M transition, the inhibitor increased filamentation in a dose-dependent manner, indicating that impaired farnesylation favours the mycelium form of P. brasiliensis. The results suggest that ras genes might have a role in dimorphism, heat shock response and in host-pathogen interaction.

Paracoccidioidomycosis in wild monkeys from Paraná State, Brazil

The aim of this study was to evaluate the seroprevalence of Paracoccidioides brasiliensis infection in wild New World monkeys (Cebus sp. and Alouatta caraya). A total of 93 animals (Cebus sp., n = 68 and Alouatta caraya, n = 25) were captured in the Paraná River basin, Paraná State, Brazil and the serum samples were analyzed by ELISA and immunodiffusion using P. brasiliensis gp43 and exoantigen as antigens, respectively. The seropositivity observed by ELISA was 44.1% and 60% for Cebus sp. and A. caraya, respectively, while by immunodiffusion test Cebus sp. showed positivity of 2.9% only. No significant difference was observed in relation to age and sex. This is the first report of paracoccidioidomycosis in wild capuchin monkeys and in wild-black and golden-howler monkeys. The high positivity to P. brasiliensis infection in both species evaluated in our study and the positivity by immunodiffusion test in Cebus sp. suggest that natural disease may be occurring in wild monkeys living in paracoccidioidomycosis endemic areas.

Immunization with radioattenuated yeast cells of Paracoccidioides brasiliensis induces a long lasting protection in BALB/c mice

Paracoccidioides brasiliensis is the fungus agent of paracoccidioidomycosis, a chronic systemic disease prevalent in Latin America. The aim of the present work was to evaluate the protection elicited by the immunization of BALB/c mice with radioattenuated yeast cells of P. brasiliensis. The immunization promoted a long lasting protection against highly infective yeast forms of P. brasiliensis. A 99.5% decrease in CFUs recovery was verified 90 days post challenge. At the same time the levels of IgG2a and IFN-gamma were high while a very low production of IL-10 and IL-5 was verified, suggesting that a Th1 pattern was dominant. This work shows the potential of radioattenuated yeast cells for the development of vaccines against fungi infections.

Analysis of memory T cells in the human paracoccidioidomycosis before and during chemotherapy treatment

Memory T cell populations in patients with paracoccidioidomycosis (PCM) were analyzed before and after chemotherapy treatment. Peripheral blood mononuclear cells (PBMC) collected from patients infected by Paracoccidioides brasiliensis or from non-infected individuals were stimulated in vitro with either membrane and extra-cellular antigens (MEXO) or yeast cell antigen preparation (PbAg) of P. brasiliensis. An increase in the level of CD4(+) memory T cells was determined in PBMC from PCM patients before (NT) and after treatment (TR) and in those with PCM relapsed (RE) compared to that from non-infected controls (NINF). The CD8(+) memory T cells were increased in PBMC from RE patients stimulated with MEXO, but not in NT or TR. The distribution of memory B cells did not differ between NT and TR patients, while a significant elevation was determined in RE patients and higher antibody levels were also detected. The cytokine analysis showed low production of IFN-gamma by cells from RE patients compared with NT or TR patients. In contrast, high production of IL-4 was detected in NT and RE patients, and moderate levels were produced by RE patients. These results suggest that IFN-gamma production may participate in the maintenance of immunological memory in the acquired protection against P. brasiliensis infection and this data can contribute to future development of successful treatment of PCM to avoid relapsing.

The relative importance of CD4+ and CD8+T cells in immunity to pulmonary paracoccidioidomycosis

Protective immunity in paracoccidioidomycosis (PCM) is believed to be mediated by cellular immunity, but the role of T cell subsets has never been investigated. The aim of this study was to characterize the function of CD4+ and CD8+ T cells in the immunity developed by susceptible, intermediate and resistant mice after P. brasiliensis infection. In susceptible mice, depletion of CD4+ T cells did not alter disease severity and anergy of cellular immunity but diminished antibody production. Anti-CD8 treatment led to increased fungal loads, but restored DTH reactivity. In resistant mice, both CD4+ and CD8+ T cells control fungal burdens and cytokines although only the former regulate DTH reactions and antibody production. In the intermediate strain, deficiency of whole T and CD8+ T cells but not of CD4+ T or B cells led to increased mortality rates. Thus, in pulmonary PCM: (a) irrespective of the host susceptibility pattern, fungal loads are mainly controlled by CD8+ T cells, whereas antibody production and DTH reactions are regulated by CD4+ T cells; (c) CD4+ T cells play a protective role in the resistant and intermediate mouse strains, whereas in susceptible mice they are deleted or anergic; (d) genetic resistance to PCM is associated with concomitant CD4+ and CD8+ T cell immunity secreting type 1 and type 2 cytokines.

Prostaglandin E(2) production by high and low virulent strains of Paracoccidioides brasiliensis

The production of prostaglandins (PGs) during fungal infections could be an important suppressor factor of host immune response. Host cells are one source of prostaglandin E(2) (PGE(2)); however another potential source of PGE(2) is the fungal pathogen itself. Thus, both host and fungal PGE2 production is theorized to play a role in pathogenesis, being critical for growth of the fungus and to modulate the host immune response. The purpose of this work was to investigate if high and low virulent strains of Paracoccidioides brasiliensis have the capacity to produce PGE(2) in vitro, and if this production was related to the fungal growth. The results demonstrated that both strains of P. brasiliensis produce high levels of PGE(2) and the treatment with indomethacin, a cyclooxygenase inhibitor, significantly reduced the production of this mediator, as well as the viability of the fungus. Thus, our data indicate that PGE(2) is produced by P. brasiliensis by a cyclooxygenase-dependent metabolic pathway, and its production is required for fungal survival. This discovery reveals an important factor that has potentially great implications for understanding the mechanisms of immune deviation during infection.

Protection induced in BALB/c mice by the high-molecular-mass (hMM) fraction of Paracoccidioides brasiliensis

Paracoccidioidomycosis (PCM) is a granulomatous disease caused by a dimorphic fungus, Paracoccidioides brasiliensis. The present study investigated the protective activity of the P. brasiliensis high-molecular-mass (hMM) fraction (approximately 380 kDa) in experimental murine PCM. In the first step, lymphocyte proliferation and production of IFNgamma (but not IL-4) were observed in "in vitro" spleen cells (from female BALB/c mice infected (i.v.) with P. brasiliensis) that were stimulated with hMM fractions. In the second step, female BALB/c mice were previously immunized (s.c.) with hMM fraction (25 microg/protein = F-25 and 50 microg/protein = F-50), and the colony-forming units (CFU) of the lung and spleen, the histopathological characteristics of the granulomatous lesions, and plasmatic gp43 soluble antigens and anti-hMM IgG levels were analyzed at 28 and 56 days after infection. The lung and liver CFU were lower in mice previously immunized with the hMM fraction (P < 0.05). The granulomatous lesions revealed a greater degree of compaction and organization, with no dissemination of the fungus to other organs. Lower soluble antigen levels (P < 0.05) and higher IgG anti-hMM fraction (P < 0.05) were observed in immunized groups. The results for CFU, histopathology and antigenemia suggest that the hMM fraction has a protective effect in experimental paracoccidioidomycosis in BALB/c mice.

T-cell recognition of Paracoccidioides brasiliensis gp43-derived peptides in patients with paracoccidioidomycosis and healthy individuals

Vaccines with synthetic peptides induce the immune response to epitopes that bind to several HLA alleles. By using a TEPITOPE algorithm, we selected and analyzed the T-cell responses of peripheral blood mononuclear cells from 29 paracoccidioidomycosis (PCM) patients to peptides of the immunodominant gp43 antigen of Paracoccidioides brasiliensis, the causative agent of PCM.

Role of iron in the nitric oxide-mediated fungicidal mechanism of IFN-gamma-activated murine macrophages against Paracoccidioides brasiliensis conidia

Iron is an essential growth element of virtually all microorganisms and its restriction is one of the mechanisms used by macrophages to control microbial multiplication. Paracoccidioides brasiliensis, the agent of paracoccidioidomycosis, an important systemic mycosis in Latin America, is inhibited in its conidia-to-yeast conversion in the absence of iron. We studied the participation of iron in the nitric oxide (NO)-mediated fungicidal mechanism against conidia. Peritoneal murine macrophages activated with 50U/mL of IFN-gamma or treated with 35 µM Deferoxamine (DEX) and infected with P. brasiliensis conidia, were co-cultured and incubated for 96 h in the presence of different concentrations of holotransferrin (HOLO) and FeS0(4). The supernatants were withdrawn in order to assess NO2 production by the Griess method. The monolayers were fixed, stained and observed microscopically. The percentage of the conidia-to-yeast transition was estimated by counting 200 intracellular propagules. IFN-gamma-activated or DEX-treated Mthetas presented marked inhibition of the conidia-to-yeast conversion (19 and 56%, respectively) in comparison with non-activated or untreated Mthetas (80%). IFN-gamma-activated macrophages produced high NO levels in comparison with the controls. Additionally, when the activated or treated-macrophages were supplemented with iron donors (HOLO or FeSO4), the inhibitory action was reversed, although NO production remained intact. These results suggest that the NO-mediated fungicidal mechanism exerted by IFN-gamma-activated macrophages against P. brasiliensis conidia, is dependent of an iron interaction.

Background selection at the chitin synthase II (chs2) locus in Paracoccidioides brasiliensis species complex

In fungi, chitin synthases have been classified into five classes according to differences in regions of high sequence conservation. The current investigation was initiated to examine the causes for the polymorphism patterns found in a class II chitin synthase gene (chs2) of Paracoccidioides brasiliensis, in an attempt to determine the evolutionary forces affecting the chitin synthesis metabolic pathway. Neutrality tests were applied to the chs2 sequences exhibited by P. brasiliensis species complex. According to these tests and based on non-synonymous differences, P. brasiliensis data rejected the null hypothesis for a pure drift mutational process owing to a large excess of unique polymorphisms. In contrast, the synonymous and intron site differences did not reject the null hypothesis. This pattern appears consistent with weak selection against most amino acid changes, in which the effect of background selection was not detectable at synonymous nor at intron sites.

Diagnosis of paracoccidioidomycosis by a dot blot assay using a recombinant Paracoccidioides brasiliensis p27 protein

A variety of immunological methods have proven useful for Paracoccidioidomycosis (PCM) diagnosis; however, they are often time consuming and many lack sensitivity and specificity, partially attributed to the use of crude antigens, which give cross reactivity. Until now, attempts to clone and express Paracoccidioides brasiliensis immunodominant antigens have presented difficulties of process and problems of cost. In an attempt to obtain a more rapid, sensitive, and specific test for PCM diagnosis, we subcloned the P. brasiliensis p27 gene and used the recombinant protein as the antigen in dot blot assays to evaluate its usefulness in paracoccidioidomicosis diagnosis. The development of an optimised procedure for p27 recombinant protein purification and production led to an easier and less expensive process than the one previously used in our laboratory and allowed the availability of enough purified protein for its evaluation as the antigen in the dot blot assays. In these assays, antibodies present in ten serum samples from seven patients with PCM recognised the recombinant protein showing a sensitivity of 100% with a specificity of 98%. These results confirm the value of the 27-kDa recombinant antigen in the serodiagnosis of paracoccidioidomycosis and that the dot blot format is an alternative to the immunoenzymatic assay procedure.

Adrenal function in 23 children with paracoccidioidomycosis

Adrenal involvement by Paracoccidioides brasiliensis was described at necropsies and in many clinical studies, but only in adults. Therefore, the aim of this study was to evaluate adrenal function in children with paracoccidioidomycosis. Twenty-three children with the systemic form of paracoccidioidomycosis were evaluated and divided in two Groups: Group A (n = 8) included children before treatment and Group B (n = 15) children after the end of treatment. Plasma cortisol (basal and after ACTH test), ACTH, renin activity, aldosterone, sodium and potassium were measured. They were within normal range in all cases, except for renin activity and aldosterone, which were elevated in some cases. Group A patients showed basal and post-ACTH cortisol levels significantly greater than Group B patients. The results showed that adrenal function was not compromised in these children with paracoccidioidomycosis.

Expression of antibodies directed to Paracoccidioides brasiliensis glycosphingolipids during the course of paracoccidioidomycosis treatment

Paracoccidioidomycosis (PCM) is a granulomatous disease caused by the dimorphic fungus Paracoccidioides brasiliensis. The immunoglobulin classes and isotypes of antibodies directed to acidic glycosphingolipids (GSLs) and glucosylceramide of P. brasiliensis were determined by enzyme-linked immunosorbent assay of sera from 31 PCM patients. The reactivities of 38 serum samples were analyzed by considering the stage of treatment: before antifungal treatment (n = 10), during 1 to 4 months of treatment (T1-4; n = 9), during 5 to 12 months of treatment (T5-12; n = 9), and posttreatment (PT; n = 10). Sera from healthy subjects (n = 12) were used as controls. Only the GSL Pb-1 antigen, which presents the carbohydrate structure Galfbeta1-6(Manalpha1-3)Manbeta1, was reactive with the PCM patient sera. The PCM patient sera did not react with Pb-2, which lacks the Galf residue and which is considered the biosynthetic precursor of Pb-1, indicating that the Galf residue is essential for antibody reactivity. The Pb-1 glycolipid from nontreated patients elicited a primary immune response with immunoglobulin M (IgM) production and subsequent switching to IgG1 production. The IgG1 titer increased after the start of antifungal treatment (T1-4 group), and general decreases in the anti-Pb-1 antibody titers were observed after 5 months of treatment (T5-12 and PT groups). The Pb-1 antigen, an acidic GSL with terminal Galf residue, has potential application as an elicitor of the host immune response in patients with PCM.

Intercellular adhesion molecule-1 is required for the early formation of granulomas and participates in the resistance of mice to the infection with the fungus Paracoccidioides brasiliensis

The migration of leukocytes to inflammatory sites elicited by Paracoccidioides brasiliensis is supposed to be coordinated by cytokines and chemokines. Here, we investigated the role of intercellular adhesion molecule-1 (ICAM-1) in recruiting inflammatory cells to lungs of mice infected with P. brasiliensis and in determining the outcome of the disease. Expression of ICAM-1 was up-regulated on T lymphocytes after infection with the fungus, and its expression was dependent on interferon-gamma, tumor necrosis factor-alpha, and interleukin-12. Moreover, the absence of ICAM-1 resulted in high susceptibility to the infection and delayed formation of granulomatous lesions. In addition, the absence of ICAM-1 resulted in increased growth and dissemination of fungus, decreased number of CD3+CD4+ and CD3+CD8+ T cells, and increased production of interleukin-4 in the inflammatory site. The organization of a granulomatous reaction in mice deficient of ICAM-1 was delayed, starting only on day 60 after infection, whereas in wild-type mice it was complete on day 30 of infection. These data show that ICAM-1 is effectively involved in cellular migration and in the organization of the granulomatous lesion caused by the fungus P. brasiliensis.

Interleukin-10 and Tumor Necrosis Factor–α Single Nucleotide Gene Polymorphism Frequency in Paracoccidioidomycosis

Allelic variants of cytokine genes seem to be involved in mechanisms of resistance or susceptibility to several diseases. The aim of this study was to investigate the frequency of genotypes with the tumor necrosis factor-alpha TNF-alpha gene polymorphism G/A at position -308 and the IL-10 gene polymorphism G/A at position -1082, and to verify a possible association of these polymorphisms with paracoccidioidomycosis (PCM) caused by Paracoccidioides brasiliensis. Genotyping was performed by allele-specific polymerase chain reaction (ASPCR) and restriction fragment length polymorphism (RFLP) on genomic DNA isolated of granulocytes from 54 PCM patients and 31 noninfected individuals. The analysis of SNP at position -1082 IL-10 showed a high frequency of GA genotype in both patients and controls (51% and 55%, respectively), while the allelic frequency showed 54% of G allele in the patients and 66% of A allele in the controls. The GG genotype was more frequent in patients (85%) and controls (68%) when we analyze the SNP at position -308 of TNF-alpha gene. Otherwise, 91% of PCM patients and 84% of noninfected individuals carried the G allele in -308 TNF-alpha SNP. Stimulation of cells from individuals with PCM phenotyped as A+ (GA or AA genotypes) presented elevation of TNF-alpha producing cells when compared with IL-10-producer cells. These findings reinforce the critical role of IL-10 and TNF-alpha in the paracoccidioidomycosis and can strongly suggest that the genetic screening of the -308G/A and -1082G/A polymorphisms may be a valid tool for identification of subjects needing a more appropriate therapy.

Cytokeratin expression in pseudoepitheliomatous hyperplasia of oral paracoccidioidomycosis

Paracoccidioidomycosis (Pmycosis) is one the most prevalent deep systemic mycoses in Latin America. It is characterized by granulomatous inflammation and pseudoepitheliomatous hyperplasia. Cytokeratins (CKs) are a group of intermediate filaments of epithelial cells and their expression varies according to the epithelium type, differentiation and pathological processes. This study describes cytokeratin expression as examined by immunohistochemistry, in 28 cases of oral Pmycosis involving the buccal mucosa, lip, gingiva and hard palate. Expression of CKs in the basal layer of the epithelium in pseudoepitheliomatous hyperplasia of Pmycosis was similar to that in normal oral mucosa (NOM), but in Pmycosis CK1 and CK10 were not expressed in the spinous and superficial layers of the lip, gingiva or hard palate, and, in the spinous and superficial layers of the lip and buccal mucosa, CK14 was positive in contrast to NOM where it was negative. In Pmycosis, CK6 was more frequently expressed in the spinous layer of the lip, gingiva and hard palate, but nevertheless CK16 expression was decreased in the spinous and superficial layers of the gingiva and hard palate. We conclude that pseudoepitheliomatous hyperplasia in oral Pmycosis shows a different pattern of CK expression, particularly CKs 1, 10 and 14, compared with NOM.

Diagnosis of Paracoccidioidomycosis by detection of antigen and antibody in bronchoalveolar lavage fluids

Paracoccidioidomycosis (PCM) is a systemic infection caused by the fungus Paracoccidioides brasiliensis and is believed to be the leading cause of fungal pulmonary infection. In this study, we used an inhibition enzyme-linked immunosorbent assay to diagnose pulmonary PCM based on the detection of 43-kDa and 70-kDa molecules in bronchoalveolar lavage fluids. The results were compared with results obtained by classical methods for antibody detection.

Cell organisation, sulphur metabolism and ion transport-related genes are differentially expressed in Paracoccidioides brasiliensis mycelium and yeast cells

BACKGROUND

Mycelium-to-yeast transition in the human host is essential for pathogenicity by the fungus Paracoccidioides brasiliensis and both cell types are therefore critical to the establishment of paracoccidioidomycosis (PCM), a systemic mycosis endemic to Latin America. The infected population is of about 10 million individuals, 2% of whom will eventually develop the disease. Previously, transcriptome analysis of mycelium and yeast cells resulted in the assembly of 6,022 sequence groups. Gene expression analysis, using both in silico EST subtraction and cDNA microarray, revealed genes that were differential to yeast or mycelium, and we discussed those involved in sugar metabolism. To advance our understanding of molecular mechanisms of dimorphic transition, we performed an extended analysis of gene expression profiles using the methods mentioned above.

RESULTS

In this work, continuous data mining revealed 66 new differentially expressed sequences that were MIPS(Munich Information Center for Protein Sequences)-categorised according to the cellular process in which they are presumably involved. Two well represented classes were chosen for further analysis: (i) control of cell organisation - cell wall, membrane and cytoskeleton, whose representatives were hex (encoding for a hexagonal peroxisome protein), bgl (encoding for a 1,3-beta-glucosidase) in mycelium cells; and ags (an alpha-1,3-glucan synthase), cda (a chitin deacetylase) and vrp (a verprolin) in yeast cells; (ii) ion metabolism and transport - two genes putatively implicated in ion transport were confirmed to be highly expressed in mycelium cells - isc and ktp, respectively an iron-sulphur cluster-like protein and a cation transporter; and a putative P-type cation pump (pct) in yeast. Also, several enzymes from the cysteine de novo biosynthesis pathway were shown to be up regulated in the yeast form, including ATP sulphurylase, APS kinase and also PAPS reductase.

CONCLUSION

Taken together, these data show that several genes involved in cell organisation and ion metabolism/transport are expressed differentially along dimorphic transition. Hyper expression in yeast of the enzymes of sulphur metabolism reinforced that this metabolic pathway could be important for this process. Understanding these changes by functional analysis of such genes may lead to a better understanding of the infective process, thus providing new targets and strategies to control PCM.

Microsatellite analysis of three phylogenetic species of Paracoccidioides brasiliensis

Paracoccidioides brasiliensis is the etiological agent of paracoccidioidomycosis, an important human systemic mycosis in Latin America. Recently, the existence of three different phylogenetic species (S1, PS2, and PS3) of P. brasiliensis was demonstrated. Despite being genetically isolated, all three species were capable of inducing disease in both humans and animals, although lower virulence has been found with the PS2 species. The available molecular methods developed to characterize and type strains have not been useful for assigning isolates to the described species, creating the need for molecular markers capable of distinguishing genetically isolated groups. Here, we describe a PCR and sequencing-based microsatellite marker system that is stable, easy to assay, adaptable to large series of isolates, and discriminatory enough to be used as a typing system in identifying the three proposed species of P. brasiliensis. In addition, this system provides an unambiguous tool for strain discrimination between two (S1 and PS2) of the three phylogenetic species.

Paracoccidioides brasiliensis: attenuation of yeast cells by gamma irradiation

Paracoccidioides brasiliensis is the agent of paracoccidioidomycosis, the most prevalent mycosis in Latin America, and currently there is no effective vaccine. The aim of this study was to attenuate the yeast form of P. brasiliensis by gamma irradiation for further studies on vaccine research. Paracoccidioides brasiliensis (strain Pb 18) cultures were irradiated at doses between 0.5 and 8.0 kGy. After each dose the viability, reproductive ability and protein metabolism were evaluated. The comparison between the antigenic profile of irradiated and control yeast was made by Western blot and the virulence evaluated by the inoculation in C(57)Bl/J6 mice. At 6.5 kGy the yeast lost its reproductive capacity. The viability and the incorporation of [L-(35)S]-methionine were the same in control and up to 6.5 kGy irradiated cells, but 6.5 kGy-irradiated yeast secreted 40% less proteins. The Western blot profile was clearly similar in control and 6.5 kGy-irradiated yeast. No colony-forming unit (CFU) could be recovered from the tissues of the mice infected with the radioattenuated yeast. We concluded that for P. brasiliensis yeast it is possible to find a dose in which the pathogen loses its reproductive ability and virulence, while retaining its viability, metabolic activity and the antigenic profile.

Drugs for treating paracoccidioidomycosis

BACKGROUND

Paracoccidioidomycosis is a fungal infection found in particular geographic localities in Latin America. Treatment can last for up to two years is often associated with complications, including relapse, but people may die without it.

OBJECTIVES

To evaluate drugs used for treating paracoccidioidomycosis.

SEARCH STRATEGY

We searched the Cochrane Infectious Diseases Group Specialized Register (January 2006), CENTRAL (The Cochrane Library 2005, Issue 4), PubMed (1966 to January 2006), EMBASE (1974 to January 2006), LILACS (1982 to January 2006), conference proceedings, and reference lists. We also contacted researchers and pharmaceutical companies.

SELECTION CRITERIA

Randomized controlled trials comparing drugs for treating people with paracoccidioidomycosis.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial eligibility and methodological quality, and extracted data, including adverse events.

MAIN RESULTS

One trial with 42 participants met the inclusion criteria that compared imidazoles (itraconazole and ketoconazole) with sulfadiazine. No difference was detected for cure or clinical improvement, or serological titres after 10 months of treatment, and there was no difference detected in adverse events.

AUTHORS' CONCLUSIONS

The small number of participants and the short follow-up period impede definitive conclusions.