Cytokines produced by susceptible and resistant mice in the course of Paracoccidioides brasiliensis infection

Paracoccidioidomycosis (PCM) is the most prevalent deep mycosis in Latin America and presents a wide spectrum of clinical manifestations. We established a genetically controlled murine model of PCM, where A/Sn mice develop an infection which mimics the benign disease (immune responses which favor cellular immunity) and B10.A animals present the progressive disseminated form of PCM (preferential activation of B cells and impairment of cellular immune responses). To understand the immunoregulatory phenomena associated with resistance and susceptibility in experimental PCM, A/Sn and B10.A mice were studied regarding antigen-elicited secretion of monokines (TNF-a and TGF-ß) and type-1 (IL-2 and IFN-g) and type-2 (IL-4,5,10) cytokines. Total lymph node cells from resistant mice infected ip with P. brasiliensis produced early and sustained levels of IFN-g and IL-2; type-2 cytokines (IL-4 and IL-5) started to appear 8 weeks after infection. In contrast, susceptible mice produced low levels of IFN-g concomitant with significant levels of IL-5 and IL-10 early in the infection. In the chronic phase of the disease, susceptible animals presented a transitory secretion of IL-2, and IL-4. In the pulmonary infection IL-4, IL-5 and IL-10 were preferentially detected in the lung cells washings of susceptible animals. After in vitro challenge with fungal antigens, normal peritoneal macrophages from B10.A mice secreted high levels of TGF-ß and low levels of TNF-a. In contrast, macrophages from A/Sn animals released high levels of TNF-a associated with a small production of TGF-ß. The in vivo depletion of IFN-g not only abrogated the resistance of A/Sn mice but also diminished the relative resistance of B10.A animals. The in vivo depletion of IL-4 did not alter the disease outcome, whereas administration of rIL-12 significantly enhanced resistance in susceptible animals. Taken together, these results suggest that an early secretion of high levels of TNF-a and IFN-g followed by a sustained secretion of IL-2 and IFN-g plays a dominant role in the resistance mechanisms to P. brasiliensis infection. In contrast, an early and ephemeral secretion of low levels of TNF-a and IFN-g associated with production of IL-5, IL-10 and TGF-ß characterizes the progressive disease of susceptible animals

Efficient subsequence matching over large video databases

Video similarity matching has broad applications such as copyright detection, news tracking and commercial monitoring, etc. Among these applications, one typical task is to detect the local similarity between two videos without the knowledge on positions and lengths of each matched subclip pair. However, most studies so far on video detection investigate the global similarity between two short clips using a pre-defined distance function. Although there are a few works on video subsequence detection, all these proposals fail to provide an effective query processing mechanism. In this paper, we first generalize the problem of video similarity matching. Then, a novel solution called consistent keyframe matching (CKM) is proposed to solve the problem of subsequence matching based on video segmentation. CKM is designed with two goals: (1) good scalability in terms of the query sequence length and the size of video database and (2) fast video subsequence matching in terms of processing time. Good scalability is achieved by employing a batch query paradigm, where keyframes sharing the same query space are summarized and ordered. As such, the redundancy of data access is eliminated, leading to much faster video query processing. Fast subsequence matching is achieved by comparing the keyframes of different video sequences. Specifically, a keyframe matching graph is first constructed and then divided into matched candidate subgraphs. We have evaluated our proposed approach over a very large real video database. Extensive experiments demonstrate the effectiveness and efficiency of our approach

Lysozyme plays a dual role against the dimorphic fungus Paracoccidioides brasiliensis A lisozima desempenha um papel duplo contra o fungo dimórfico Paracoccidioides brasiliensis

In order to determine the role of lysozyme, an antimicrobial peptide belonging to the innate immune system, against the dimorphic fungus Paracoccidioides brasiliensis, co-cultures of the MH-S murine alveolar macrophages cell line with P. brasiliensis conidia were done; assays to evaluate the effect of physiological and inflammatory concentrations of lysozyme directly on the fungus life cycle were also undertaken. We observed that TNF-&#945;-activated macrophages significantly inhibited the conidia to yeast transition (p = 0.0043) and exerted an important fungicidal effect (p = 0.0044), killing 27% more fungal propagules in comparison with controls. Nonetheless, after adding a selective inhibitor of lysozyme, the fungicidal effect was reverted. When P. brasiliensis propagules were exposed directly to different concentrations of lysozyme, a dual effect was observed. Physiologic concentrations of the enzyme facilitated the conidia-to-yeast transition process (p < 0.05). On the contrary, inflammatory concentrations impaired the normal temperature-dependant fungal transition (p < 0.0001). When yeast cells were exposed to lysozyme, irrespective of concentration, the multiple-budding ability was badly impaired (p < 0.0001). In addition, ultra-structural changes such as subcellular degradation, fusion of lipid vacuoles, lamellar structures and interruption of the fibrilar layer were observed in lysozyme exposed conidia. These results suggest that lysozyme appears to exert a dual role as part of the anti-P. brasiliensis defense mechanisms.<br>Com a finalidade de determinar o papel da lisozima, um peptídeo antimicrobiano que pertence ao sistema imune inato, contra o fungo dimórfico Paracoccidioides brasiliensis, foram feitas co-culturas de uma linha de macrófagos alveolares murinos (MH-S) com as conídias do fungo na presença ou não do TNF-&#945; e/ou um inibidor da lisozima; também foram feitos ensaios que avaliaram o efeito das concentrações fisiológicas e inflamatórias de lisozima diretamente sobre o ciclo de vida do fungo. Observamos que os macrófagos ativados com a citoquina tiveram um efeito significativo na inibição da transição conídia/levedura (p = 0,0043) e exerceram um efeito fungicida importante (p = 0,0044), matando mais de 27% das propágulas do fungo em comparação com os macrófagos não ativados. No entanto, após ser o inibidor seletivo da lisozima adicionado, o efeito fungicida foi revertido. Quando os propágulos do fungo foram expostos diretamente a diferentes concentrações da lisozima, um duplo efeito foi observado. Assim, as concentrações fisiológicas da enzima facilitaram o processo de transição conídia-levedura (p < 0,05). Contrariamente, as concentrações inflamatórias prejudicaram a transição fúngica (p < 0,0001). Quando as leveduras foram expostas a qualquer concentração de lisozima, sua capacidade de multi-brotação foi gravemente prejudicada (p < 0,0001). Além disso, mudanças ultra-estruturais, como a sub degradação, a fusão dos vacúolos dos lípidos, estruturas lamelares e interrupção da camada fibrilar foram observadas em conídios expostos à lisozima. Estes resultados sugerem que a lisozima poderia exercer um duplo papel no mecanismo antifúngico contra P. brasiliensis

Serological follow-up of patients with paracoccidioidomycosis treated with itraconazole using Dot-blot, ELISA and Western-blot

Twenty-seven mycologically proven cases of paracoccidioidomycosis (PCM) were treated with itraconazole (100-200 mg/day in month 1 and 100 mg/day until month 6-8) and evaluated clinically and serologically, up to 3.5 years post-therapy, using Dot-blot and ELISA for measuring the titers of IgG, IgA and IgM anti-P. brasiliensis antibodies and Western-blot for determining IgG, IgA and IgM antibodies against the antigen components of the fungus. Before treatment, 81.5% (Dot-blot) and 84% (ELISA) of the patients presented elevated IgG anti-P. brasiliensis antibody titers which dropped slightly with treatment. On the other hand, the percentages of pre-treatment high-titered sera for IgA and IgM anti-P.brasiliensis were lower (5l.9% and 5l.8%: Dot-blot; 16.5 and 36%: ELISA, respectively) but the titers tended to become negative more frequently with treatment. Prior to treatment, the percentages of positivity for IgG, IgA and IgM anti-P.brasiliensis antibodies in Western-blot were 96%, 20.8% and 41.6%, respectively. Antigens with molecular weights varying from 16-78 kDa, from 21-76 kDa and from 27-78 kDa were reactive for IgG, IgA and IgM antibodies, respectively. The most frequently reactive antigenic components had molecular weights of 27, 33 and 43 kDa for IgG, and 70 for IgA and IgM antibodies. During the period of study, the patients responded well to treatment. The present data confirm the diversity and complexity of the humoral response in PCM, and the importance of utilizing different serological tests to detect IgG, IgA and IgM anti-P. brasiliensis antibodies<br>Vinte e sete pacientes portadores de paracoccidioidomicose (PCM) foram tratados com itraconazole (100-200 mg/dia no primeiro mês e 100 mg/dia até 6-8 meses) e avaliados sob o ponto de vista clínico e sorológico, até 3 e meio anos após o início do tratamento, utilizando-se os testes de Dot-blot e ELISA para medir os títulos de anticorpos IgG, IgA e IgM anti-P. brasiliensis, e Western-blot para determinar os anticorpos IgG, IgA e IgM contra os componentes antigênicos do fungo. Antes do tratamento, 81,5% (Dot-blot) e 84% (ELISA) dos pacientes apresentaram títulos elevados de anticorpos IgG anti-P. brasiliensis, que decresceram levemente com o tratamento. Por outro lado, as porcentagens de soros pré-tratamento com títulos elevados para anticorpos IgA e IgM foram menores (51,9% e 51,8%: Dot-blot; 16% e 36 %: ELISA, respectivamente); com o tratamento, entretanto, estes títulos tenderam mais frequentemente a se negativar. Antes do tratamento, as porcentagens de positividade para anticorpos IgG, IgA e IgM, avaliados por Western-blot, foram 96%, 20,8% e 41,6%, respectivamente. Componentes antigênicos de massas moleculares variando entre 16-78 kDa, 21-76 kDa e 27-78 kDa reagiram com anticorpos das classes IgG, IgA e IgM, respectivamente, As frações antigênicas com massas moleculares de 27, 33 e 43 kDa foram as mais frequentemente reativas com anticorpos da classe IgG, e a de 70 kDa para anticorpos IgA e IgM. Todos os pacientes apresentaram remissão da sintomatologia com o tratamento, durante o período de estudo. Os dados do presente trabalho confirmam a diversidade e a complexidade da resposta humoral dos pacientes com PCM e reforçam a importância de se utilizar diferentes testes sorológicos para se detectar anticorpos IgG, IgA e IgM anti- P. brasiliensis