Brasiliensis Antigen Research Articles

Seroprevalence of sporotrichosis infection in cats living in the Buenos Aires epizootic area.

This study aimed to perform a seroepidemiological survey on the prevalence of sporotrichosis among cats living in the Northern area of Buenos Aires, where a four-fold increase of Sporothrix brasiliensis infections were diagnosed during the last decade. For this purpose, an in-house indirect ELISA test sensitized with S. brasiliensis crude antigens was used. The ELISA test showed 100.0% sensitivity and 95.0% specificity. Antibodies against S. brasiliensis antigens were detected in 3.7% (9/241) of healthy cats evaluated, suggesting likely exposure or infection to this fungus. This ELISA test would be a valuable screening tool for diagnosing sporotrichosis and for seroepidemiological surveys.

Paracoccidioidesbrasiliensis induces IL-32 and is controlled by IL-15/IL-32/vitamin D pathway in vitro

Paracoccidioidomycosis (PCM) is a systemic fungal disease caused by Paracoccidioides spp., whose clinical outcome depends on immune response. Interleukin 32 (IL-32) is a cytokine present in inflammatory and infectious diseases, including bacterial, virus and protozoan infections. Its role in fungal disease remains unclear. The axis IL-15, IL-32 and vitamin D leads to microbicidal capacity against intracellular pathogens. Thus, the aims of this study were to investigate the production of IL-32 during Paracoccidioides spp. infection and whether this cytokine and IL-15 can increase P. brasiliensis control in a vitamin D dependent manner. IL-32 was highly detected in oral lesions from patients with PCM. In addition, high production of this cytokine was intracellularly detected in peripheral blood mononuclear cells (PBMCs) from healthy donors after exposure to particulated P. brasiliensis antigens (PbAg). The IL-32γ isoform was predominantly expressed, but there was mRNA alternative splicing for IL-32α isoform. The induction of IL-32 was dependent on Dectin-1 receptor. Infection of PBMCs with P. brasiliensis yeasts did not significantly induce IL-32 production even after activation with exogenous IFN-γ or IL-15 treatments. Although IL-15 was a potent inducer of IL-32 production, treatment with this cytokine did not increase the fungal control unless vitamin D was present in high levels. In this case, both IL-15 and IL-32 increased fungicidal activity of PBMCs. Together, data showed that IL-32 is present in lesions of PCM, PbAg induces IL-32, and the axis of IL-15/IL-32/vitamin D can contribute to control fungal infection. The data suggest that exposure to molecules from P. brasiliensis, as β-glucans, is needed to induce IL-32 production since only heat-killed and sonicated P. brasiliensis yeasts were able to increase IL-32, which was blocked by anti-Dectin-1 antibodies. This is the first description about IL-15/IL-32/vitamin D pathway role in P. brasiliensis infection.

Monocyte-Derived Dendritic Cells Can Revert In Vitro Antigen-Specific Cellular Anergy in Active Human Paracoccidioidomycosis.

We investigated the in vitro effects of two Paracoccidioides brasiliensis antigens on monocyte-derived dendritic cells (moDCs) from patients with paracoccidioidomycosis (PCM). MoDCs from patients with active or treated PCM and non-PCM subjects were generated, stimulated with TNF-α, and P. brasiliensis antigens, 43 kDa glycoprotein (gp43) and cell-free antigen (CFA), and analyzed by flow cytometry and enzyme-linked immunosorbent assays (ELISA). Our data revealed that patients with PCM had a high frequency of HLA-DR+ cells, but the treated group had more CD86+ cells with increased IL-12p40. Patients with active PCM had more CD80+ moDCs, and as a novel finding, large amounts of chemokine (C-C motif) ligand 18 (CCL18) in the supernatants from their in vitro moDC cultures. Both gp43- and CFA-stimulated moDCs from the patients with PCM successfully reverted the in vitro antigen-specific anergy, inducing a proliferative response. However, CFA-stimulated moDCs led to higher lymphoproliferation, with increased IFN-γ and TNF-α in the cells from the patients with active PCM compared with gp43. These original results combined with constant IL-10 and increased IL-12p40 levels suggest that a more complex antigen, such as CFA, may be a better inducer of the protective Th1 immune response than purified gp43 is, and a suitable target for future studies on anti-P. brasiliensis dendritic cell (DC)-based vaccines.

SEROPREVALENCE OF FELINE LEISHMANIASIS IN PARANÁ USING ANTIGENS FROM DIFFERENT SPECIES OF LEISHMANIA SPP / SOROPREVALÊNCIA DA LEISHMANIOSE FELINA NO PARANÁ UTILIZANDO-SE ANTÍGENOS DE DIFERENTES ESPÉCIES DE LEISHMANIA SPP

In domestic cats, the number of infections caused by parasites of the genus Leishmania is becoming increasingly significant, although the role of felines in this cycle is not yet clear. The aim of this study was to observe the prevalence of anti- Leishmania spp. using different antigens: Leishmania Viannia brasiliensis , Leishmania Leishmania amazonensis and Leishmania Leishmania infantum , in serological samples from domestic cats, from castration efforts carried out in the city of Londrina / PR, from 2015 to 2016. The test was used in indirect ELISA (Enzyme-Linked Immunosorbent Assay) serological diagnosis, with the aforementioned antigens for plaque sensitization. Of the total of 199 samples analyzed, 69 (34.67%) were considered reagents for Leishmania spp., 37 samples (18.59%) were considered reagents for L. (L.) amazonensis ; 40 samples (20.10%) for L. (V.) brasiliensis and 24 (12.06%) for L. (L.) infantum . In 42 samples (21.10%) reactivity to ELISA was observed in more than one of the antigens used. A higher prevalence of antibodies was observed when using the L. (V.) brasiliensis antigen, confirming that this is the most reported species in the state of Parana. We can conclude that antibodies against Leishmania spp. are circulating in the studied feline population; in addition, the use of the Leishmania antigen species most prevalent in the study region is indicated for obtaining more reliable results.

Hookworm exposure decreases human papillomavirus uptake and cervical cancer cell migration through systemic regulation of epithelial-mesenchymal transition marker expression

Persistent infection with human papillomavirus (HPV) is responsible for nearly all new cervical cancer cases worldwide. In low- and middle-income countries (LMIC), infection with helminths has been linked to increased HPV prevalence. As the incidence of cervical cancer rises in helminth endemic regions, it is critical to understand the interaction between exposure to helminths and the progression of cervical cancer. Here we make use of several cervical cancer cell lines to demonstrate that exposure to antigens from the hookworm N. brasiliensis significantly reduces cervical cancer cell migration and global expression of vimentin and N-cadherin. Importantly, N. brasiliensis antigen significantly reduced expression of cell-surface vimentin, while decreasing HPV type 16 (HPV16) pseudovirion internalization. In vivo infection with N. brasiliensis significantly reduced vimentin expression within the female genital tract, confirming the relevance of these in vitro findings. Together, these findings demonstrate that infection with the hookworm-like parasite N. brasiliensis can systemically alter genital tract mesenchymal markers in a way that may impair cervical cancer cell progression. These findings reveal a possible late-stage treatment for reducing cervical cancer progression using helminth antigens.

Phenotypic and functional evaluations of peripheral blood monocytes from chronic-form paracoccidioidomycosis patients before and after treatment.

BackgroundParacoccidioidomycosis (PCM) is systemic mycosis caused by the thermal dimorphic fungus of genus Paracoccidioides, leading to either acute/subacute (AF) or chronic (CF) clinical forms. Numerous CF patients after treatment exhibit sequels, such as pulmonary and adrenal fibrosis. Monocytes are cells that are involved in the inflammatory response during active infection as well as in the fibrogenesis. These cells comprise a heterogeneous population with distinct phenotypic and functional activities. The scope of this study was to identify changes regarding functional and phenotypical aspects in monocytes comparing CF PCM patients on antifungal treatment versus non-treated patients (PMC-p).MethodsTwenty-three CF PCM composed of 11 non-treated patients (NTG) and 12 patients in apparent cure (ACG) were studied. Sixteen healthy individuals were used as control group (CG). Monocyte subsets were determined by immunophenotyping based on CD14 and CD16 expression. Cellular function was measured in vitro with and without stimulation with lipopolysaccharide (LPS) and P. brasiliensis exoantigen (PbAg) for 24 hours. Independent samples were compared using unpaired t tests, dependent samples were analyzed by paired t-test. Groups of more than two independent samples were analyzed using an ANOVA, with Tukey's post-test. Significance was set up at p <0.05.ResultsOur results showed high counts of peripheral blood CD14+CD16+ and CD14+CD16++ monocytes in untreated PCM-p accompanied by intense production of pro-inflammatory cytokines (IL-1β and TNF-α) and profibrotic growth factors (TGF-β1 and bFGF) by monocytes challenged with P. brasiliensis antigens. After the introduction of antifungal therapy, the counts of CD14+CD16+ cells returned to baseline while CD14+CD16++ counts remained high. Interestingly, counts of CD14+CD16++ monocytes remained elevated even 52 ± 7 months after successful antifungal treatment. Furthermore, the ACG-patients showed preserved pro-inflammatory activity in the presence of specific antigen stimuli and high spontaneous production of TNF-α by monocytes.ConclusionsInfection with Paracoccidioides leads to initiation of a specific proinflammatory response by monocytes of PCM-p during active disease and in the apparent cure. A profibrotic profile by monocytes was observed only at admission. Furthermore, PCM-p with apparent cure showed high spontaneous production of TNF-α and high counts of CD14+CD16++ monocytes, probably induced by hypoxia duo to fibrotic sequelae.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-014-0552-x) contains supplementary material, which is available to authorized users.

Paracoccidioides lutzii Plp43 is an active glucanase with partial antigenic identity with P. brasiliensis gp43.

Background Paracoccidioides brasiliensis and P. lutzii cause paracoccidioidomycosis (PCM). P. brasiliensis main diagnostic antigen is glycoprotein gp43, and its peptide sequence is 81% identical with a P. lutzii ortholog here called Plp43. P. lutzii (“Pb01-like”) apparently predominates in Midwestern/Northern Brazil, where high percentages of false-negative reactions using P. brasiliensis antigens have recently been reported. The aim of this work was to produce recombinant Plp43 to study its antigenic identity with gp43.MethodologyWe expressed rPlp43 as a secreted major component in Pichia pastoris and studied its reactivity in immunoblot with PCM patients' sera from Southwestern and Midwestern Brazil.Principal FindingsWe showed that rPlp43 is not glycosylated and bears glucanase activity. The protein did not react with anti-gp43 monoclonal antibodies in immunoblot, suggesting absence of the corresponding gp43 epitopes. Nevertheless, common epitope(s) might exist, considering that gp43-positive PCM sera recognized rPlp43 in immunoblot, while gp43-negative sera (33 out of 51) from patients resident in Midwestern Brazil were also rPlp43-negative. Two genotyped P. lutzii were from patients with gp43-negative sera, suggesting that non-reactive sera are from patients infected with this species.ConclusionOur data suggest that gp43 and Plp43 bear one or only a few common epitopes and that gp43 cannot be used in diagnosis of PCM patients infected with P. lutzii probably because Plp43 is poorly expressed during infection.

Immunomodulatory effect of diethylcarbamazine in mice infected with Nocardia brasiliensis.

We tested whether diethylcarbamazine (DEC) or ivermectin (IVM), both antiparasitic drugs with reported immunomodulatory properties, were able to affect the immune system to potentiate host defense mechanisms and protect against actinomycetoma in a mouse model. Male BALB/c mice of 10-12 weeks of age were injected with either Nocardia brasiliensis or saline solution. Recorded were the effects of a treatment by DEC (6 mg/kg per os daily for one week) or IVM (200 μg/kg subcutaneously on days 1 and 3) on (i) the development of mycetoma lesion, (ii) the expression of reactive oxygen intermediates (ROI) by phagocytes, (iii) the proliferation index of lymphocytes and (iv) antibody production of IgG and IgM. After an initial lesion in all mice, DEC inhibited a full development and progression of actinomycetoma resulting in a reduced lesion size (p < 0.001). IVM had no inhibitory effect on the development of mycetoma. Furthermore, DEC treatment was associated with a significant enhancement of ROI expression (p < 0.05) by polymorphonuclear neutrophils at day 3 after infection. Lymphocyte proliferation in response to N. brasiliensis antigens and concanavalin A in DEC-treated group was higher than in non-treated group at day 21 and 28 postinfection (p < 0.01). Significant changes in antibody response were not observed. By all parameters tested, DEC was superior to IVM regarding immunostimulatory potency. In conclusion, DEC expressed an in vivo influence on the immune status during the infection by N. brasiliensis leading to retrogression of the mycetoma and increasing cellular immune responses. Our findings may indicate a potential use of DEC as a putative adjuvant in infectious disease or vaccination.

Differential correlation between interleukin patterns in disseminated and chronic human paracoccidioidomycosis.

In an attempt to understand better the immunoregulatory disorders in paracoccidioidomycosis (PCM), the possible correlation between interleukin pattern, lymphoproliferation, C-reactive protein (CRP) and specific antibody levels was investigated in the polarized clinical forms of this disease. We studied 16 PCM patients, eight with the disseminated disease (four under treatment and four non-treated) and eight with the chronic disease. The patients with disseminated disease exhibited high antibody titres specific to Paracoccidioides brasiliensis antigen compared with patients with the chronic form of disease. Tumour necrosis factor (TNF), IL-1, IL-6 and CRP in the serum of non-treated disseminated PCM patients were increased, which correlated positively with the low mitogenic response of peripheral blood mononuclear cells (PBMC) to phytohaemagglutinin (PHA) (P < 0.01) and with the high antibody titres (P < 0.001) of these patients. Moreover, we found in the disseminated PCM patients positive correlations between IL-1 and IL-6 (P = 0.0007); IL-1 and TNF (P = 0.0045); IL-1 and IL-6 with the high antibody titres (P = 0.0834 and P = 0.0631, respectively); IL-1, IL-6 and TNF with CRP levels. By contrast, no correlations were found with those interleukins in the treated disseminated and chronic patients or in controls. It was interesting to find an inverse correlation between IL-4 and antibody production in non-treated disseminated PCM (r = -0.4770); moreover, a significant correlation (P = 0.0820) was found in chronic PCM patients with respect to the low level of either IL-4 and antibody titres against fungus antigen. Chronic PCM patients also had IL-2 levels inversely correlated with antibody production (r = -0.6313; P = 0.0628). Inverse correlations were also observed between IL-2 and IL-6 levels in non-treated disseminated patients (P = 0.0501) and between IL-2 and IL-4 in chronic patients (P = 0.0131). The inflammatory cytokines might have a pivotal role in the genesis and in control of some aspects of the disease, such as granulomatous reaction, hypergammaglobulinaemia and depression of T cell-mediated immunity in PCM.

Fundamentals of paracoccidioidomycosis treatment

AbstractParacoccidioidomycosis (PCM) is the most important mycosis in Latin America. The etiological agent is the fungus, Paracoccidioides brasiliensis. Approximately 1 million people are infected with the fungus, 10% of whom will show symptoms of the disease. However, clinical and laboratorial studies addressing the diagnosis for this disease are both scarce and diverse in terms of definition. Nevertheless, two main advances were included in the portfolio of available diagnostic methods for paracoccidioidomycosis during the last decades: the detection of antibodies against P. brasiliensis antigens by serological methods, and the detection of the fungi DNA in peripheral blood and fragments of lesions using the polymerase chain reaction (PCR) assay and species‐specific primers. Normally, the treatment of PCM is quite prolonged because of the immunosuppressed profile of the patients and the ability of P. brasiliensis to survive in the tissues even after long‐term treatment. Case reports indicate that azoles and sulfa compounds can produce positive results in less severe cases of PCM. However, for acute cases of the disease in immunocompromised patients or in cases of neuroparacoccidioidomycosis, there is no standard treatment. Thus, there is a need to establish a standard treatment protocol within the context of the patient clinical profile. Moreover, drug availability to public institutions is an important issue, since new drugs, e.g., second‐generation azoles, the echinocandines and immunomodulatory drugs, are not yet available in public hospitals and clinics. Drug Dev Res 72:528–537, 2011. © 2011 Wiley‐Liss, Inc.

Granulocyte macrophage colony-stimulating factor enhances the modulatory effect of cytokines on monocyte-derived multinucleated giant cell formation and fungicidal activity against Paracoccidioides brasiliensis

Multinucleated giant cells (MGC) are cells present in characteristic granulomatous inflammation induced by intracellular infectious agents or foreign materials. The present study evaluated the modulatory effect of granulocyte macrophage colony-stimulating factor (GM-CSF) in association with other cytokines such as interferon-gamma (IFN-γ), tumour necrosis factor-alpha, interleukin (IL)-10 or transforming growth factor beta (TGF-β1) on the formation of MGC from human peripheral blood monocytes stimulated with Paracoccidioides brasiliensis antigen (PbAg). The generation of MGC was determined by fusion index (FI) and the fungicidal activity of these cells was evaluated after 4 h of MGC co-cultured with viable yeast cells of P. brasiliensis strain 18 (Pb18). The results showed that monocytes incubated with PbAg and GM-CSF plus IFN-γ had a significantly higher FI than in all the other cultures, while the addition of IL-10 or TGF-β1 had a suppressive effect on MGC generation. Monocytes incubated with both pro and anti-inflammatory cytokines had a higher induction of foreign body-type MGC rather than Langhans-type MGC. MGC stimulated with PbAg and GM-CSF in association with the other cytokines had increased fungicidal activity and the presence of GM-CSF also partially inhibited the suppressive effects of IL-10 and TGF-β1. Together, these results suggest that GM-CSF is a positive modulator of PbAg-stimulated MGC generation and on the fungicidal activity against Pb18.

Serological Evidence of Paracoccidioides brasiliensis Infection in Chickens from Paraná and Mato Grosso do Sul States, Brazil

The objective of this study was to detect antibodies against Paracoccidioides brasiliensis in free-range and caged chickens Gallus domesticus. Initially, the humoral immune response of two chickens immunized with P. brasiliensis was evaluated. Both animals showed the production of antibodies to gp43, the major P. brasiliensis antigen. The seroepidemiological survey was conducted in chickens from the Pantanal region in Mato Grosso do Sul State (free-range n=40) and from northern region of Paraná State (free-range n=100, caged n=43). The serum samples were analyzed by indirect ELISA using gp43 as antigen. The positivity observed in free-range chickens from Mato Grosso do Sul (55%) was significantly higher (P=0.0001) than in free-range chickens from Paraná State (16%). In contrast to the free-range chickens, no positivity was observed in the caged chickens (P=0.003). This is the first report showing serological evidence of P. brasiliensis infection in chickens. The results suggest that free-range chickens are more frequently infected by P. brasiliensis, probably due to the constant contact with soil than caged chickens and could be useful as epidemiological markers of paracoccidioidomycosis.

Lack of Galectin-3 Drives Response to Paracoccidioides brasiliensis toward a Th2-Biased Immunity

There is recent evidence that galectin-3 participates in immunity to infections, mostly by tuning cytokine production. We studied the balance of Th1/Th2 responses to P. brasiliensis experimental infection in the absence of galectin-3. The intermediate resistance to the fungal infection presented by C57BL/6 mice, associated with the development of a mixed type of immunity, was replaced with susceptibility to infection and a Th2-polarized immune response, in galectin-3-deficient (gal3−/−) mice. Such a response was associated with defective inflammatory and delayed type hypersensitivity (DTH) reactions, high IL-4 and GATA-3 expression and low nitric oxide production in the organs of infected animals. Gal3−/− macrophages exhibited higher TLR2 transcript levels and IL-10 production compared to wild-type macrophages after stimulation with P. brasiliensis antigens. We hypothesize that, during an in vivo P. brasiliensis infection, galectin-3 exerts its tuning role on immunity by interfering with the generation of regulatory macrophages, thus hindering the consequent Th2-polarized type of response.

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.

Fungicidal activity of human monocyte-derived multinucleated giant cells induced in vitro by Paracoccidioides brasiliensis antigen

Multinucleated giant cells (MGC) are characteristic cells in granulomatous disorders such as paracoccidioidomycosis (PCM) and also are formed in vitro from peripheral blood mononuclear cells by several stimuli. In this study, the authors investigated in vitro formation of MGC derived from monocytes of healthy individuals, stimulated with Paracoccidioides brasiliensis antigen (PbAg), compared with other stimuli such as IFN-gamma and supernatant of Con-A-stimulated peripheral blood mononuclear cells (CM-ConA). Besides, the fungicidal activity of monocytes and monocyte-derived MGC challenged with P. brasiliensis were compared, at a ratio of one fungus per 50 monocytes. Results demonstrated that PbAg, IFN-gamma, and CM-ConA stimuli were able to induce MGC generation, with fusion indices significantly higher than control cultures. Striking results were observed when MGC induced by PbAg and IFN-gamma presented higher fungicidal activity than monocytes, submitted to the same stimuli, showing a better capacity of these cells to kill P. brasiliensis. In summary, the results suggest that PbAg is able to induce MGC generation, and these cells presented higher fungicidal activity against P. brasiliensis than monocytes.

Diversity in Paracoccidioides brasiliensis . The PbGP43 gene as a genetic marker

Paracoccidioides brasiliensis is a temperature-dependent dimorphic fungus and the agent of paracoccidioidomycosis (PCM), which is prevalent in rural workers of Latin American countries. Until a decade ago, most of the studies involving P. brasiliensis used clinical isolates, since environmental samples from soil are difficult to obtain. More recently, P. brasiliensis has been isolated from infected wild and domestic animals, especially from the nine-banded armadillo Dasypus novemcinctus in Brazil. Over the years, diversity within the species has been observed at several phenotypic levels. The present review will discuss the reports focusing on genetic polymorphism, which culminated with the detection of P. brasiliensis phylogenetic species as a result of a multilocus study. Polymorphism in the PbGP43 gene is detailed. This gene encodes fungal glycoprotein gp43, a dominant P. brasiliensis antigen largely studied in the last two decades for its importance in diagnosis, immune protection, and adhesive properties to extracellular matrix-associated proteins. Fungal traits associated with genetic groups are discussed.

Identification and characterization of a novel antigen from the nematode Nippostrongylus brasiliensis recognized by specific IgE

Identification and characterization of IgE-inducing antigens are important for elucidating the mechanisms involved in IgE-mediated immune responses in allergic diseases and parasite infections. While many allergens have been characterized, little is known about parasite antigens inducing specific IgE following infection. In order to identify antigens from the nematode Nippostrongylus brasiliensis, we generated an IgE-producing B cell hybridoma from N. brasiliensis-infected C57BL/6 mice and constructed a cDNA phage display library from N. brasiliensis. We successfully cloned and expressed an N. brasiliensis antigen (Nb-Ag1) that showed specific binding to anti-N. brasiliensis IgE. Nb-Ag1 localized to the pharynx of adult N. brasiliensis, suggesting that Nb-Ag1 is a potential pharyngeal gland antigen. Nb-Ag1-specific IgE could be detected in the serum of N. brasiliensis-infected mice, but only for a short time and only following a challenge infection. In contrast, local administration of Nb-Ag1 during primary, secondary and tertiary infections induced Nb-Ag1-specific IgE-mediated active cutaneous anaphylaxis. Therefore, amongst the high amounts of polyclonal total IgE, low levels of parasite-specific IgE responses are induced during primary helminth infections. Here, we show that even such low levels of parasite-specific IgE are sufficient to prime mast cells in vivo and mediate degranulation.

Helminths, allergic disorders and IgE‐mediated immune responses: Where do we stand?

Th2 responses induced by allergens or helminths share many common features. However, allergen-specific IgE can almost always be detected in atopic patients, whereas helminth-specific IgE is often not detectable and anaphylaxis often occurs in atopy but not helminth infections. This may be due to T regulatory responses induced by the helminths or the lack of helminth-specific IgE. Alternatively non-specific IgE induced by the helminths may protect from mast cell or basophil degranulation by saturating IgE binding sites. Both of these mechanisms have been implicated to be involved in helminth-induced protection from allergic responses. An article in the current issue of the European Journal of Immunology describes the generation of an anti-Nippostrongylus brasiliensis-specific IgE antibody which was used to identify a novel N. brasiliensis antigen (Nb-Ag1). The authors demonstrated that Nb-Ag1 specific IgE could only be detected for a short period of time during infection, and that these levels were sufficient to prime mast cells thereby leading to active cutaneous anaphylaxis after the application of Nb-Ag1. This is the first report clearly showing that a low level of helminth-specific IgE, transiently produced, is able to induce mast cell degranulation in the presence of large amounts of polyclonal IgE.

Kinetics of IFN-gamma, TNF-alpha, IL-10 and IL-4 production by mononuclear cells stimulated with gp43 peptides, in patients cured of paracoccidioidomycosis

We analyzed the kinetics of cytokine production by mononuclear cells from 17 patients who had been treated for paracoccidioidomycosis, using the stimulus of gp43 peptide groups (43 kDa glycoprotein of Paracoccidioides brasiliensis) at 0.1 and 1 microM, gp43 (1 microg/ml) and crude Paracoccidioides brasiliensis antigen (PbAg; 75 microg/ml). IFN-gamma production was a maximum at 144 hours in relation to the G2 and G8 peptide groups at 1 microM and was greatest at 144 hours when stimulated by gp43 and by PbAg. The maximum TNF-alpha production was at 144 hours for the G2 group (0.1 microM) and for gp43. IL-10 production was highest after 48 and 72 hours for G7 and G6 at 1 microM, respectively. We also suggest the best time for analysis of IL4 production. These results may contribute towards future studies with gp43 peptides and encourage further investigations with the aim of understanding the influence of these peptides on the production of inflammatory and regulatory cytokines.

Generic human leukocyte antigen class II (DRB1 and DQB1) alleles in patients with paracoccidioidomycosis

Human leukocyte antigen (HLA) class II alleles are involved in antigen processing and in the presentation of antigens to T lymphocytes. Few studies have investigated HLA genes in paracoccidioidomycosis. In the present investigation, we analyzed the distribution of the HLA class II alleles DRB1 and DQB1 in 45 healthy volunteers and in 80 patients with paracoccidioidomycosis. The patients presented with various clinical forms of the disease, and allele distribution was evaluated individually in each presentation type. In patients with the unifocal chronic form of the disease, a mild clinical presentation in which lesions are restricted or localized, the HLA allele most commonly seen was DRB1*11 (p<0.039). This suggests that the participation of HLA antigens may influence the outcome of the host-parasite interaction in paracoccidioidomycosis, regulating the immune response to Paracoccidioides brasiliensis antigens.