Detection of the basement membrane-degrading proteolytic activity of Paracoccidioides brasiliensis after SDS-PAGE using agarose overlays containing Abz-MKALTLQ-EDDnp

We have characterized, in the Paracoccidioides brasiliensis yeast phase, an exocellular SH-dependent serine proteinase activity against Abz-MKRLTL-EDDnp and analogous fluorescent-quenched peptides, and showed that it is also active against constituents of the basement membrane in vitro. In the present study, we separated the components of P. brasiliensis culture filtrates by electrophoresis and demonstrated that the serine-thiol exocellular proteinase has a diffuse and heterogeneous migration by SDS-PAGE, localizing in a region between 69 and 43 kDa. The hydrolytic activity was demonstrable after SDS-PAGE using buffered agarose overlays of Abz-MKALTLQ-EDDnp, following incubation at 37oC, and detection of fluorescent bands with a UV transilluminator. Hydrolysis was more intense when incubation was carried out at basic pH, and was completely inhibited with 2.5 mM PMSF and partially with sodium 7-hydroxymercuribenzoate (2.5 mM p-HMB), suggesting its serine-thiol nature. A proteolytic band with similar characteristics was observed in conventional gelatin zymograms, but could not be correlated with a silver-stained component. Detection of the serine-thiol proteinase in substrate gels after SDS-PAGE provides a useful way of monitoring purification of the basement membrane degrading enzyme.

The low efficiency of dendritic cells and macrophages from mice susceptible to Paracoccidioides brasiliensis in inducing a Th1 response

In the present study we evaluated T cell proliferation and Th lymphokine patterns in response to gp43 from Paracoccidioides brasiliensis presented by isolated dendritic cells from susceptible and resistant mice. T cell proliferation assays showed that dendritic cells from susceptible mice were less efficient than those from resistant mice. The pattern of T cell lymphokines stimulated by dendritic cells was always Th1, although the levels of IL-2 and IFN-gamma were lower in T cell cultures from susceptible mice. To determie whether different antigen-presenting cells such as macrophages and dendritic cells stimulated different concentrations of Th1 lymphokines, the production of IFN-gamma and IL-2 was measured. It was observed that dendritic cells were more efficient than macrophages in stimulating lymphoproliferation in resistant mice. However, no significant difference was observed for IFN-gamma or IL-2 production. When cells from susceptible mice were used, macrophages were more efficient in stimulating lymphoproliferation than dendritic cells, but no difference was observed in the production of Th1 cytokine. Taken together, these results suggest the lower efficiency of dendritic cells and macrophages from B10.A mice in stimulating T cells that secrete Th1 lymphokines in vitro, an effect that may be involved in the progression of the disease in vivo.

Parinaud's oculoglandular syndrome associated with paracoccidioidomycosis

The authors report one case of Parinaud's oculoglandular syndrome associated with Paracoccidioides brasiliensis infection. No other medical report of this condition was found in the medical literature available at Index Medicus and Medline. The eye involvement has been rather uncommon in paracoccidioidomycosis and this report emphasizes the possibility of this kind of presentation making it also necessary to include paracoccidioidomycosis among the several known causes of Parinaud's oculoglandular syndrome.

Paracoccidioidomycosis in organ transplant recipient: case report

Paracoccidioidomycosis is a common disease in Latin America but it is rare in organ transplant recipient patients. We report on a case of such mycosis in a renal transplant recipient. The patient presented with a large lung cavity on the left lower lobe, a rare radiological presentation of paracoccidioidomycosis. Unusual clinical and radiological manifestations of Paracoccidioides brasiliensis infection can occur in immunocompromised patients.

Long-term outcome of neuroparacoccidioidomycosis treatment

INTRODUCTION: Neuroparacoccidioidomycosis (NPCM) is a term used to describe the invasion of the central nervous system by the pathogenic fungus Paracoccidioides brasiliensis. NPCM has been described sporadically in some case reports and small case series, with little or no focus on treatment outcome and long-term follow-up. METHODS: All patients with NPCM from January 1991 to December 2006 were analyzed and were followed until December 2009. RESULTS: Fourteen (3.8%) cases of NPCM were identified out of 367 patients with paracoccidioidomycosis (PCM). A combination of oral fluconazole and sulfamethoxazole/trimethoprim (SMZ/TMP) was the regimen of choice, with no documented death due to Paracoccidioides brasiliensis infection. Residual neurological deficits were observed in 8 patients. Residual calcification was a common finding in neuroimaging follow-up. CONCLUSIONS: All the patients in this study responded positively to the association of oral fluconazole and sulfamethoxazole/trimethoprim, a regimen that should be considered a treatment option in cases of NPCM. Neurological sequela was a relatively common finding. For proper management of these patients, anticonvulsant treatment and physical therapy support were also needed.

Paracoccidioides cerebriformis Moore, 1935. MYCOLOGIC AND IMMUNOCHEMICAL STUDY

The present study concern on mycologic and immunochemical data obtained from two samples of a fungus considered as belonging to the species Paracoccidioides cerebriformis described by Moore in 1935, and maintained since then on Sabouraud’s agar in the mycology collection of the Instituto de Medicina Tropical de São Paulo. After 60 years, the samples exhibited the same characteristics described by Moore (1935). However, experimental lesions did not resulted in guinea-pigs inoculated intratesticularly. The dominant antigen in Paracoccidioides brasiliensis, 43 kDa glicoprotein (gp43), could not be demonstrated by SDS PAGE and Western blotting. Immunoelectrophoresis did not demonstrated the E arch of cathodic migration using a policlonal anti gp43 serum. According to these findings, it is concluded that the fungus described by Moore (1935) as P. cerebriformis does not belong to the genus Paracoccidioides. Paracoccidioidomycosis should therefore be considered as resulting from infection by a single species, Paracoccidioides brasiliensis (Splendore, 1912) as asserted by Almeida (1930). Further studies, through molecular biology methods, could identify the mentioned fungus

PREVALENCE OF PARACOCCIDIOIDOMYCOSIS INFECTION BY INTRADERMAL REACTION IN RURAL AREAS IN ALFENAS, MINAS GERAIS, BRAZIL

This study aimed to estimate the prevalence of paracoccidioidal infection by intradermal reaction (Delayed-Type Hypersensitivity, DTH) to Paracoccidioides brasiliensis in rural areas in Alfenas, Southern Minas Gerais (MG) State, Brazil, and to assess risk factors (gender, occupation, age, alcohol intake and smoking) associated with infection. We conducted a population-based cross-sectional study using intradermal tests with gp 43 paracoccidioidin in 542 participants, who were previously contacted by local health agents and so spontaneously attended the test. Participants underwent an interview by filling out a registration form with epidemiological data and were tested with an intradermal administration of 0.1 mL of paracoccidioidin in the left forearm. The test was read 48 hours after injection and was considered positive if induration was greater than or equal to 5 mm. Out of 542 participants, 46.67% were positive to the skin test. Prevalence increased in accordance with an increase of age. There was statistical significance only for males. Occupation, alcohol intake and smoking habits were not significantly associated with the risk of paracoccidioidomycosis infection. There is relevance of paracoccidioidomycosis infection in such rural areas, which suggests that further epidemiological and clinical studies on this mycosis should be done in the southern part of Minas Gerais State.

Experimental paracoccidioidomycosis in the mouse. III. Histopathological and immunological findings after intravenous infection in the presence or absence of previous immunization

Fifty male white Swiss mice aged 4 weeks were inoculated with 5 x 10(5) viable yeast forms of Paracoccidioides brasiliensis (strain 18). Ten of these animals had been previously immunized with particulate P. brasiliensis antigenfor 4 weeks by intradermal injection. The controls consisted of 10 animals that were only immunized and 10 animals submitted to no treatment. The animals were sacrificed 2, 4, 7,11 and 16 weeks later. We studied: 1) the anti-P. brasiliensis delayed hypersensitivity response measured by the footpad test 24 hours prior to sacrifice; 2) the specific antibody production measured by double immunodiffusion in agar gel; 3) the histopathology of lungs, liver, spleen, adrenals and kidneys. We observed that: a) the immunized animals developed more intense cell-immune responses than the infected ones; b) infection reduced the cell- immune response of the immunized animals; c) intravenous infection of mice with P. brasiliensis was characterized by a systemic and progressive granulomatous inflammation. The animals infected after previous immunization showed less extensive lung inflammation, with smaller granulomas and fewer fungi. The results indicate that the present murine model mimics some findings of the human subacute form of paracoccidioidomycosis (systemic disease with depressed cellular immunity) and that the extrapulmonary immunization scheme was able to induce a certain degree of protection of the lung from infection with P. brasiliensis

Influence of the Paracoccidioides brasiliensis14-3-3 and gp43 proteins on the induction of apoptosis in A549 epithelial cells

The fungal strain Paracoccidioides brasiliensisremains viable inside of epithelial cells and can induce apoptosis in this population. However, until now, the molecules that participate in this process remained unknown. Thus, this study evaluated the contribution of two P. brasiliensismolecules, the 14-3-3 and glycoprotein of 43 kDa proteins, which had been previously described as extracellular matrix adhesins and apoptosis inductors in human pneumocytes. Accordingly, epithelial cells were treated with these molecules for different periods of time and the expression of the apoptosis regulating-proteins Bak, Bax, Bcl-2, p53 and caspases were evaluated by terminal deoxynucleotidyl transferase dUTP nick end labelling, flow cytometry and real-time polymerase chain reaction analysis. Our results demonstrated that treatment with these molecules induces apoptosis signalling in pulmonary epithelial cells, showing the same pattern of programmed cell-death as that observed during infection with P. brasiliensis. Thus, we could conclude that P. brasiliensisuses these molecules as virulence factors that participate not only in the fungal adhesion process to host cells, but also in other important cellular mechanisms such as apoptosis.

Evaluation of different immunization protocols with P. brasiliensis antigens in Guinea pigs

The objective of the present study was to develop an efficient and reproducible protocol of immunization of guinea pigs with P. brasiliensis antigens as an animal model for future studies of protective immunity mechanisms. We tested three different antigens (particulate, soluble and combined) and six protocols in the presence and absence of Freund's complete adjuvant and with different numbers of immunizing doses and variable lenght of time between the last immunizing dose and challenge. The efficacy of the immunizing protocol was evaluated by measuring the humoral and cellular anti-P. brasiliensis immune response of the animals, using immuno-diffusion, skin test and macrophage migration inhibition test. It was observed that: 1. Three immunizing doses of the antigens induced a more marked response than two doses; 2. The highest immune response was obtained with the use of Freund's complete adjuvant; 3. Animals challenged a long time (week 6) after the last immunizing dose showed good anti-P. brasiliensis immune response; 4. The particulate antigen induced the lowest immune response. The soluble and the combined antigens were equally efficient in raising good humoral and cellular anti-P. brasiliensis immune response

Natural killer cell activity in experimental paracoccidioidomycosis of the Syrian hamster

The study evaluated the activity of NK cells during the course of experimental infection of hamsters with Paracoccidioides brasiliensis. Eigthy hamsters were infected with P. brasiliensis by intratesticular route and sacrificed at 24h, 48h, 96h, 1, 2, 4, 8 and 11 weeks of infection and compared to 40 noninfected hamsters employed as controls. These animals were submitted to the study of NK cytotoxic activity by a single-cell assay and humoral immune response by immunodiffusion and ELISA tests. The production of macrophage migration inhibitory factor in the presence of Phyto-hemagglutinin and P. brasiliensis antigen and histopathology of the lesions were evaluated at 1, 4, 8 and 11 weeks of infection. The infected animals displayed significantly high levels of NK activity during the four weeks of infection that decreased from the 8th week on when compared to controls. This impairment of NK activity was associated with depression of cell-mediated immune response and with increase in the extension of the histopathologic lesions. There was an inverse correlation between NK cell activity and specific antibody levels. The results suggest that after initial activation, NK cells were unable to control the fungus dissemination. The impairment of NK activity in the late stages of the infection might be related to immunoregulatory disturbances associated with paracoccidioidomycosis.

Cyclophosphamide effect on paracoccidioidomycosis in the rat

Paracoccidioidomycosis is an endemic fungal disease widely distributed throughout Latin America. The potent immunosuppressor cyclophosphamide (CY) has been used to modulate host immune response to Paracoccidioides brasiliensis in an experimental model. Inbred male Buffalo/Sim rats weighing 250-300 g were inoculated with 5 x 10(6) P. brasiliensis cells of the yeast phase form by intracardiac route. One group of animals was treated with 20 mg/kg body weight at days +4, +5, +6, +7, +11 and +12 post-infection (pi.), while a control group was infected alone. No mortality was recorded in either group. Treated rats presented: a) a decrease in granuloma size, which contained less fungal cells; b) a lack of specific antibodies up to 35 days pi., and c) a significant increase in the footpad swelling test (DTH) against paracoccidioidin. Splenic cell transfer from CY-treated P. brasiliensis-infected donors to recipients infected alone led to a significant increase in DTH response in the latter versus untreated infected controls. Likewise, in treated infected recipients transferred with untreated infected donor spleen cells, footpad swelling proved greater than in controls. Thus, it would seem that each successive suppressor T lymphocyte subset belonging to the respective cascade may be sensitive to repeated CY doses administered up to 12 days pi.. Alternatively, such CY schedule may induce the appearance of a T cell population capable of amplifying DTH response.

Paracoccidioidomycosis associated with acquired immunodificiency syndrome: report of seven cases

We report the clinical findings and evolution of seven patients (five men and two women), the majority of them intravenous drug users, with paracoccidioidomycosis associated to acquired immunodeficiency syndrome (AIDS). In four of the patients the paracoccidioidomycosis was restricted to the lung and in the three others was generalized with cutaneous involvement. Only two of them had lived recently in rural area, an indication of the possible reactivation of latent focal infection in the other five patients. The recognition of the role of cell-mediated immunity in host defense against Paracoccidioides brasiliensis leds to the prediction of a growing occurrence of the paracoccidioidomycosis-AIDS association in areas that are endemic for these diseases.

Virulence Factors IN Fungi OF Systemic Mycoses

Pathogenic fungi that cause systemic mycoses retain several factors which allow their growth in adverse conditions provided by the host, leading to the establishment of the parasitic relationship and contributing to disease development. These factors are known as virulence factors which favor the infection process and the pathogenesis of the mycoses. The present study evaluates the virulence factors of pathogenic fungi such as Blastomyces dermatitidis, Coccidioides immitis, Cryptococcus neoformans, Histoplasma capsulatum and Paracoccidioides brasiliensis in terms of thermotolerance, dimorphism, capsule or cell wall components as well as enzyme production. Virulence factors favor fungal adhesion, colonization, dissemination and the ability to survive in hostile environments and elude the immune response mechanisms of the host. Both the virulence factors presented by different fungi and the defense mechanisms provided by the host require action and interaction of complex processes whose knowledge allows a better understanding of the pathogenesis of systemic mycoses.

Paracoccidioides brasilienses isolates obtained from patients with acute and chronic disease exhibit morphological differences after animal passage

The basis for virulence in Paracoccidioides brasiliensis is not completely understood. There is a consensus that the sequencial in vitro subcultivation of P. brasiliensis leads to loss of its pathogenicity, which can be reverted by reisolation from animal passage. Attention to morphological and biochemical properties that are regained or demonstrated after animal passage may provide new insights into factors related to the pathogenicity and virulence of P. brasiliensis. We evaluated morphological characters: the percentage of budding cells, number of buds by cell and the diameter of 100 mother cells of yeast-like cells of 30 P. brasiliensis isolates, before and after animal passage. The isolates were obtained from patients with different clinical forms of paracoccidioidomycosis (PCM): acute form (group A, n=15) and chronic form (group C, n=15). The measurement of the yeast cell sizes was carried out with the aid of an Olympus CBB microscope coupled with a micrometer disc. We measured the major transverse and longitudinal axes of 100 viable cells of each preparation. The percentage of budding cells as also the number of buds by cell was not influenced by animal passage, regardless of the source of the strain (acute or chronic groups). The size values of P. brasiliensis isolates from groups A and C, measured before the animal passage exhibited the same behavior. After animal passage, there was a statistically significant difference between the cell sizes of P. brasiliensis isolates recovered from testicles inoculated with strains from groups A and C. The maximum diameter of mother cells from group A isolates exhibited a size of 42.1mm in contrast with 32.9mm exhibited by mother cells from group C (p<0.05). The diameter of 1500 mother cells from group A isolates exhibited a medium size of 16.0mm (SD ± 4.0), a value significantly higher than the 14.1mm (SD = ± 3.3) exhibited by 1500 mother cells from group C isolates (p<0.05). Our results reinforce the polymorphism exhibited by P. brasiliensis in biological material and the need for further investigations to elucidate the role of morphological parameters of the fungus in the natural history of the disease.