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1.
Clin Exp Immunol ; 198(2): 143-152, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31400225

RESUMO

Vaccines are considered the bedrock of preventive medicine. However, for many pathogens, it has been challenging to develop vaccines that stimulate protective, long-lasting immunity. We have developed a novel approach using ß-1,3-D-glucans (BGs), natural polysaccharides abundantly present in fungal cell walls, as a biomaterial platform for vaccine delivery. BGs simultaneously provide for receptor-targeted antigen delivery to specialized antigen-presenting cells together with adjuvant properties to stimulate antigen-specific and trained non-specific immune responses. This review focuses on various approaches of using BG particles (GPs) to develop bacterial and fungal vaccine candidates. A special case history for the development of an effective GP tularaemia vaccine candidate is highlighted.


Assuntos
Adjuvantes Imunológicos/uso terapêutico , Vacinas Bacterianas , Sistemas de Liberação de Medicamentos , Francisella tularensis/imunologia , Glucanos/uso terapêutico , Tularemia , Animais , Vacinas Bacterianas/imunologia , Vacinas Bacterianas/uso terapêutico , Humanos , Tularemia/imunologia , Tularemia/prevenção & controle , Vacinação
2.
Microbiol Spectr ; 5(4)2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28752813

RESUMO

Fungi have emerged as premier opportunistic microbes of the 21st century, having a considerable impact on human morbidity and mortality. The huge increase in incidence of these diseases is largely due to the HIV pandemic and use of immunosuppressive therapies, underscoring the importance of the immune system in defense against fungi. This article will address how the mammalian immune system recognizes and mounts a defense against medically relevant fungal species.


Assuntos
Fungos/fisiologia , Micoses/imunologia , Micoses/microbiologia , Animais , Fungos/genética , Humanos , Imunidade Inata , Infecções Oportunistas/imunologia , Infecções Oportunistas/microbiologia
3.
Med Mycol ; 40(3): 329-32, 2002 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12146766

RESUMO

We have previously demonstrated the antifungal activity of the weak bases chloroquine and quinacrine against Cryptococcus neoformans. Quinacrine, being fluorescent, was seen to be concentrated within a complex vacuolar structure within the cryptococcal cell. Here we determined the pH of this compartment using the pH-sensitive fluorescent dye, 5-(and 6-) carboxy-2',7'-dichlorofluorescein diacetate (carboxy-DCFDA). Carboxy-DCFDA was concentrated within the cryptococcal vacuole, giving a pattern of fluorescence similar to that previously observed with quinacrine. For each experiment, a standard curve of fluorescence ratio against pH was generated using buffers of defined pH containing a mixture of ionophores and inhibitors to equilibrate vacuolar pH with that of the medium. The pH of the cryptococcal vacuole of five strains was calculated to range from 5.3 to 5.9 with a mean of 5.6. This acidic pH is consistent with a model in which weak bases such as chloroquine and quinacrine are accumulated, by ion trapping within the fungal vacuole. Antifungal activity may result from the consequent disruption of pH-dependent processes as well as effects on other as yet undefined fungal targets.


Assuntos
Cryptococcus neoformans/química , Vacúolos/química , Cryptococcus neoformans/ultraestrutura , Fluoresceínas , Fluorescência , Concentração de Íons de Hidrogênio , Microscopia Confocal
6.
Proc Natl Acad Sci U S A ; 98(18): 10422-7, 2001 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-11504924

RESUMO

The fungus Cryptococcus neoformans is a major cause of morbidity and mortality in patients with impaired CD4(+) T cell function, particularly those with AIDS. To identify cryptococcal antigens that could serve as vaccine candidates by stimulating T cell responses, C. neoformans-reactive CD4(+) T cell hybridomas were generated by immunization of C57BL/6 mice and fusion of splenocytes with thymoma cells. The antigen that stimulated one of the hybridomas, designated P1D6, to produce IL-2 was purified to homogeneity by sequential anion exchange chromatography, hydrophobic interaction chromatography, and SDS/PAGE. Based on its apparent molecular mass of 98 kDa and mannosylation, the antigen of interest was named MP98. MP98 was N terminal-sequenced, and the gene encoding the protein was cloned and sequenced. Recombinant MP98, expressed in Saccharomyces cerevisiae, stimulated P1D6 to produce IL-2. Analysis of the derived 458-aa sequence of MP98 reveals an N-terminal cleavable signal sequence, a polysaccharide deacetylase domain found in fungal chitin deacetylases, and a serine/threonine-rich C-terminal region. Overall, there were 103 serine/threonine residues serving as potential O-linked glycosylation sites as well as 12 possible N-linked glycosylation sites. Thus, a C. neoformans mannoprotein has been characterized that stimulates T cell responses and has molecular properties of a chitin deacetylase.


Assuntos
Amidoidrolases/imunologia , Cryptococcus neoformans/enzimologia , Cryptococcus neoformans/imunologia , Proteínas Fúngicas/imunologia , Glicoproteínas de Membrana/imunologia , Linfócitos T/imunologia , Amidoidrolases/química , Amidoidrolases/genética , Sequência de Aminoácidos , Animais , Antígenos de Fungos/química , Antígenos de Fungos/genética , Sequência de Bases , Clonagem Molecular , Criptococose/imunologia , Cryptococcus neoformans/genética , Primers do DNA/genética , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Vacinas Fúngicas/isolamento & purificação , Hibridomas/imunologia , Masculino , Glicoproteínas de Membrana/química , Glicoproteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos C57BL , Dados de Sequência Molecular , Peso Molecular , Homologia de Sequência de Aminoácidos
7.
J Immunol ; 166(7): 4620-6, 2001 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-11254720

RESUMO

Toll-like receptors (TLR) 2 and 4 are cell surface receptors that in association with CD14 enable phagocytic inflammatory responses to a variety of microbial products. Activation via these receptors triggers signaling cascades, resulting in nuclear translocation of NF-kappa B and a proinflammatory response including TNF-alpha production. We investigated whether TLRs participate in the host response to Cryptococcus neoformans glucuronoxylomannan (GXM), the major capsular polysaccharide of this fungus. Chinese hamster ovary fibroblasts transfected with human TLR2, TLR4, and/or CD14 bound fluorescently labeled GXM. The transfected Chinese hamster ovary cells were challenged with GXM, and activation of an NF-kappa B-dependent reporter construct was evaluated. Activation was observed in cells transfected with both CD14 and TLR4. GXM also stimulated nuclear NF-kappa B translocation in PBMC and RAW 264.7 cells. However, stimulation of these cells with GXM resulted in neither TNF-alpha secretion nor activation of the extracellular signal-regulated kinase 1/2, p38, and stress-activated protein kinase/c-Jun N-terminal kinase mitogen-activated protein kinase pathways. These findings suggest that TLRs, in conjunction with CD14, function as pattern recognition receptors for GXM. Furthermore, whereas GXM stimulates cells to translocate NF-kappa B to the nucleus, it does not induce activation of mitogen-activated protein kinase pathways or release of TNF-alpha. Taken together, these observations suggest a novel scenario whereby GXM stimulates cells via CD14 and TLR4, resulting in an incomplete activation of pathways necessary for TNF-alpha production.


Assuntos
Cryptococcus neoformans/imunologia , Proteínas de Drosophila , Glicoproteínas de Membrana/fisiologia , Polissacarídeos/imunologia , Receptores de Superfície Celular/fisiologia , Transdução de Sinais/imunologia , Fator de Necrose Tumoral alfa/metabolismo , Transporte Ativo do Núcleo Celular/imunologia , Animais , Sítios de Ligação/genética , Sítios de Ligação/imunologia , Células CHO , Linhagem Celular , Cricetinae , Regulação da Expressão Gênica/imunologia , Humanos , Líquido Intracelular/imunologia , Líquido Intracelular/metabolismo , Leucócitos Mononucleares/enzimologia , Leucócitos Mononucleares/imunologia , Leucócitos Mononucleares/metabolismo , Receptores de Lipopolissacarídeos/fisiologia , Sistema de Sinalização das MAP Quinases/genética , Sistema de Sinalização das MAP Quinases/imunologia , Glicoproteínas de Membrana/genética , Camundongos , NF-kappa B/genética , NF-kappa B/metabolismo , Polissacarídeos/metabolismo , Polissacarídeos/fisiologia , Receptores de Superfície Celular/genética , Transdução de Sinais/genética , Receptor 2 Toll-Like , Receptor 4 Toll-Like , Receptores Toll-Like , Transfecção , Fator de Necrose Tumoral alfa/biossíntese , Fator de Necrose Tumoral alfa/genética
8.
J Infect Dis ; 183(6): 935-42, 2001 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-11237811

RESUMO

Recent observations demonstrated that the antimalarial drug chloroquine (CQ) can kill the opportunistic fungus Cryptococcus neoformans. Since CQ blunts lipopolysaccharide (LPS)-induced tumor necrosis factor (TNF)-alpha release, it was hypothesized that this drug would also interfere with the inflammatory response to C. neoformans and Candida albicans, another fungal opportunist. CQ inhibited TNF-alpha release from peripheral blood mononuclear cells from healthy and human immunodeficiency virus-positive donors without affecting NF-kappaB activation. CQ reduced TNF-alpha mRNA levels by a pH-dependent mechanism in a manner similar to 2 unrelated alkalizing drugs (ammonium chloride and bafilomycin), which also inhibited TNF-alpha gene expression. Although CQ inhibited release of interleukin (IL)-1beta and IL-6, it did not affect IL-10 or macrophage inflammatory protein-1alpha production. Thus, CQ interferes with fungus-induced TNF-alpha expression by a mechanism that probably depends on the alkalization of endolysosomes. This contrasts with CQ's reported pH-independent inhibition of LPS-stimulated TNF-alpha release and suggests that the mechanism of CQ's anti-inflammatory effects is stimulus specific.


Assuntos
Candida albicans/imunologia , Cloroquina/farmacologia , Cryptococcus neoformans/imunologia , Soropositividade para HIV/imunologia , Lisossomos/efeitos dos fármacos , Macrolídeos , Fator de Necrose Tumoral alfa/biossíntese , Transporte Ativo do Núcleo Celular , Cloreto de Amônio/farmacologia , Antibacterianos/farmacologia , Núcleo Celular/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Citocinas/biossíntese , Endossomos/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Humanos , Concentração de Íons de Hidrogênio/efeitos dos fármacos , Leucócitos Mononucleares/imunologia , NF-kappa B/metabolismo , Transcrição Gênica/efeitos dos fármacos , Fator de Necrose Tumoral alfa/genética
9.
Infect Immun ; 68(11): 6257-64, 2000 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11035733

RESUMO

It has long been appreciated that polymorphonuclear leukocytes (PMN) kill Cryptococcus neoformans, at least in part via generation of fungicidal oxidants. The aim of this study was to examine the contribution of nonoxidative mechanisms to the inhibition and killing of C. neoformans. Treatment of human PMN with inhibitors and scavengers of respiratory burst oxidants only partially reversed anticryptococcal activity, suggesting that both oxidative and nonoxidative mechanisms were operative. To define the mediators of nonoxidative anticryptococcal activity, PMN were fractionated into cytoplasmic, primary (azurophil) granule, and secondary (specific) granule fractions. Incubation of C. neoformans with these fractions for 18 h resulted in percent inhibition of growth of 67.4 +/- 3.4, 84.6 +/- 4.4, and 29.2 +/- 10.5 (mean +/- standard error, n = 3), respectively. Anticryptococcal activity of the cytoplasmic fraction was abrogated by zinc and depletion of calprotectin. Antifungal activity of the primary granules was significantly reduced by pronase treatment, boiling, high ionic strength, and magnesium but not calcium. Fractionation of the primary granules by reverse phase high-pressure liquid chromatography on a C(4) column over an acetonitrile gradient revealed multiple peaks with anticryptococcal activity. Of these, peaks 1 and 6 had substantial fungistatic and fungicidal activity. Peak 1 was identified by acid-urea polyacrylamide gel electrophoresis (PAGE) and mass spectroscopy as human neutrophil proteins (defensins) 1 to 3. Analysis of peak 6 by sodium dodecyl sulfate-PAGE revealed multiple bands. Thus, human PMN have nonoxidative anticryptococcal activity residing principally in their cytoplasmic and primary granule fractions. Calprotectin mediates the cytoplasmic activity, whereas multiple proteins, including defensins, are responsible for activity of the primary granules.


Assuntos
Cryptococcus neoformans/imunologia , Neutrófilos/imunologia , Atividade Bactericida do Sangue , Cromatografia Líquida de Alta Pressão , Eletroforese em Gel de Poliacrilamida , Humanos , Complexo Antígeno L1 Leucocitário , Glicoproteínas de Membrana/fisiologia , Moléculas de Adesão de Célula Nervosa/fisiologia , Neutrófilos/química , Explosão Respiratória
10.
Am J Respir Crit Care Med ; 162(3 Pt 1): 966-70, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10988114

RESUMO

Impaired adaptive immunity is the hallmark of AIDS, but the effects of human immunodeficiency virus type 1 (HIV-1) infection on innate immunity are less clear. Cryptococcus neoformans (CN) is a common AIDS-related fungal pathogen acquired by inhalation. Alveolar macrophages (AM) comprise the initial host defense in cryptococcosis and they may arrest infection before dissemination occurs. We hypothesized that HIV-1 infection of AM impairs their anti-cryptococcal activity. This was tested by infection of normal AM with the M-tropic strain HIV-1(Bal). Two weeks postinfection we measured fungistatic activity against CN by colony counting, binding, and internalization of CN by confocal microscopy and AM cell viability by Alamar Blue assay. Uninfected AM from most donors demonstrated innate fungicidal activity against CN. In HIV-1-infected AM, there was a significant reduction, and in most cases loss, of fungicidal activity compared with the uninfected AM. The reduced antifungal activity was not due to any cytotoxic effect of HIV-1, and HIV-1 infection did not impair binding or internalization of yeast by AM. Thus, the innate fungicidal activity of primary human AM is impaired after HIV-1 infection in vitro by a mechanism involving a defect of intracellular antimicrobial processing.


Assuntos
Cryptococcus neoformans/imunologia , HIV-1/patogenicidade , Macrófagos Alveolares/virologia , Células Cultivadas , Humanos , Macrófagos Alveolares/imunologia , Fagocitose/imunologia , Virulência
11.
Curr Opin Microbiol ; 3(4): 349-53, 2000 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10972492

RESUMO

The antimalarial drug chloroquine accumulates inside the macrophage phagolysosome by ion trapping where it exerts potent antifungal activity against Histoplasma capsulatum and Cryptococcus neoformans by distinct mechanisms. Chloroquine inhibits growth of H. capsulatum by pH-dependent iron deprivation, whereas it is directly toxic to C. neoformans. Clearly, clinical studies are required to document the potential therapeutic efficacy of chloroquine or related congeners as adjuvant therapy in fungal disease. Moreover, the diversity of pathogenic microorganisms inhibited and/or killed by chloroquine makes this drug an attractive candidate for prophylactic therapy.


Assuntos
Antifúngicos/farmacologia , Cloroquina/farmacologia , Cryptococcus neoformans/efeitos dos fármacos , Histoplasma/efeitos dos fármacos , Fagossomos/efeitos dos fármacos , Animais , Criptococose/tratamento farmacológico , Criptococose/microbiologia , Histoplasmose/tratamento farmacológico , Histoplasmose/microbiologia , Humanos , Concentração de Íons de Hidrogênio , Ferro/metabolismo , Camundongos , Fagossomos/microbiologia
12.
J Infect Dis ; 182(1): 283-9, 2000 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10882608

RESUMO

Chloroquine at 10 microM enhances the activity of macrophages against Cryptococcus neoformans but does not directly inhibit cryptococcal growth. The antifungal activity of higher chloroquine concentrations likely to be found within the acidic cryptococcal phagosome was tested. Concentrations of >/=30 microM inhibited cryptococcal growth, and there was fungal killing at concentrations of >/=100 microM. Activity was dependent on physiologic temperature and pH. Quinacrine was 50-fold more active than chloroquine, and concentrations as low as 100 nM enhanced macrophage anticryptococcal activity. Quinacrine was concentrated within a vacuolar system within the fungal cell and highly concentrated within intracellular C. neoformans. Ammonium chloride and bafilomycin A both inhibited cryptococcal growth, suggesting that the activity of chloroquine and quinacrine may in part be due to disruption of pH-dependent processes. These findings add to the known spectrum of activity of chloroquine and quinacrine. These, and related compounds, may have utility for the treatment of cryptococcosis.


Assuntos
Antifúngicos/farmacologia , Cloroquina/farmacologia , Cryptococcus neoformans/efeitos dos fármacos , Macrolídeos , Quinacrina/farmacologia , Antibacterianos/farmacologia , Divisão Celular/efeitos dos fármacos , Cryptococcus neoformans/metabolismo , Combinação de Medicamentos , Inibidores Enzimáticos/farmacologia , Testes de Sensibilidade Microbiana
13.
J Immunol ; 165(3): 1534-40, 2000 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-10903761

RESUMO

Chloroquine (CQ) is a lysosomotropic weak base with over 60 years of clinical use for the treatment of malaria and rheumatologic disorders. Consistent with its anti-inflammatory properties, CQ has been shown to interfere with TNF-alpha release from mononuclear phagocytes. Because it is unclear how CQ mediates these immunomodulatory effects, we set out to elucidate its mechanism of action. CQ exhibited dose-dependent inhibition of LPS-induced TNF-alpha release from human PBMC at therapeutically attainable concentrations. Additional studies to determine the specificity of this effect showed that although CQ reduced IL-1beta and IL-6 release, secretion of RANTES was unaffected. CQ acted by reducing TNF-alpha mRNA accumulation without destabilizing its mRNA or interfering with NF-kappaB nuclear translocation or p50/p65 isoform composition of DNA-binding complexes. Intracellular cytokine staining indicated that CQ reduced TNF-alpha production pretranslationally without interfering with TNF-alpha processing or release. We utilized bafilomycin A1 pretreatment to block the pH-dependent trapping of CQ in endosomes and lysosomes. Although bafilomycin A1 alone did not interfere with TNF-alpha expression, preincubation augmented the ability of CQ to reduce TNF-alpha mRNA levels, suggesting that CQ did not act by a lysosomotropic mechanism. Using confocal microscopy, we showed that bafilomycin A1 pretreatment resulted in a dramatic redistribution of quinacrine, a fluorescent congener of CQ, from cytoplasmic vacuoles to the nucleus. These data indicate that CQ inhibits TNF-alpha gene expression without altering translocation of NF-kappaB p50/p65 heterodimers. This dose-dependent effect occurs over a pharmacologically relevant concentration range and does not require pH-dependent lysosomotropic accumulation of CQ.


Assuntos
Cloroquina/farmacologia , Regulação da Expressão Gênica/imunologia , Imunossupressores/farmacologia , Lipopolissacarídeos/antagonistas & inibidores , Lisossomos/imunologia , Lisossomos/metabolismo , Macrolídeos , Fator de Necrose Tumoral alfa/antagonistas & inibidores , Fator de Necrose Tumoral alfa/genética , Antibacterianos/farmacologia , Transporte Biológico/efeitos dos fármacos , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Quimiocina CCL5/metabolismo , Proteínas de Ligação a DNA/metabolismo , Relação Dose-Resposta a Droga , Relação Dose-Resposta Imunológica , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Concentração de Íons de Hidrogênio , Interleucina-1/antagonistas & inibidores , Interleucina-1/metabolismo , Interleucina-6/antagonistas & inibidores , Interleucina-6/metabolismo , Leucócitos Mononucleares/efeitos dos fármacos , Leucócitos Mononucleares/imunologia , Leucócitos Mononucleares/metabolismo , Lipopolissacarídeos/imunologia , Lisossomos/efeitos dos fármacos , NF-kappa B/metabolismo , Subunidade p50 de NF-kappa B , Biossíntese de Proteínas/efeitos dos fármacos , Biossíntese de Proteínas/imunologia , Processamento de Proteína Pós-Traducional/efeitos dos fármacos , Processamento de Proteína Pós-Traducional/imunologia , RNA Mensageiro/antagonistas & inibidores , RNA Mensageiro/metabolismo , Fator de Transcrição RelA , Transcrição Gênica/efeitos dos fármacos , Transcrição Gênica/imunologia , Fator de Necrose Tumoral alfa/metabolismo
14.
J Infect Dis ; 181(2): 733-6, 2000 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10669365

RESUMO

Hypoproduction of the cytokines interleukin (IL)-12 and interferon (IFN)-gamma is thought to contribute to the impaired immunity seen in human immunodeficiency virus (HIV)-infected persons. The effects of priming with IL-15 on the production of IL-12 and IFN-gamma by stimulated peripheral blood mononuclear cells (PBMC) from HIV-seronegative and -seropositive donors were studied. Stimuli included 3 pathogens that commonly infect HIV-positive persons-Cryptococcus neoformans, Candida albicans, and Mycobacterium tuberculosis-plus Staphylococcus aureus. Following IL-15 priming of HIV-negative PBMC, pathogen-stimulated IL-12 and IFN-gamma production increased 5-58-fold. However, for the HIV-positive PBMC, IL-15 priming did not lead to significant increases in pathogen-stimulated IL-12 production and caused only modest increases in IFN-gamma production. These data suggest that IL-15 alone may be insufficient to correct the defect in IL-12 and IFN-gamma production in HIV-positive persons.


Assuntos
Infecções por HIV/imunologia , Interferon gama/biossíntese , Interleucina-12/biossíntese , Interleucina-15/imunologia , Leucócitos Mononucleares/imunologia , Infecções Oportunistas Relacionadas com a AIDS/imunologia , Infecções Oportunistas Relacionadas com a AIDS/microbiologia , Doadores de Sangue , Candida albicans/imunologia , Cryptococcus neoformans/imunologia , Soronegatividade para HIV/imunologia , Humanos , Ativação Linfocitária , Mycobacterium tuberculosis/imunologia
15.
J Infect Dis ; 181(2): 791-4, 2000 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10669379

RESUMO

The beta-chemokine macrophage inflammatory protein (MIP)-1alpha, MIP-1beta, and RANTES are critical for recruitment of inflammatory cells into infected tissue. Moreover, by binding to the human immunodeficiency virus (HIV) coreceptor CCR5, release of these chemokines could influence the course of HIV infection. beta-chemokine gene expression and release was determined by ELISA and RNase protection assay, respectively, in peripheral blood mononuclear cells (PBMC) from HIV-negative and -positive persons stimulated with Candida albicans and Cryptococcus neoformans, 2 fungi common in HIV-infected persons. Gene expression and/or release of all 3 chemokines was seen in response to both fungi although C. albicans was more potent than C. neoformans. Fungal stimulated chemokine production by HIV-positive PBMC was similar to that in HIV-negative PBMC, suggesting that the scant inflammatory response often seen in AIDS patients with cryptococcosis and candidiasis is not secondary to suboptimal beta-chemokine release.


Assuntos
Candida albicans/imunologia , Quimiocinas CC/biossíntese , Cryptococcus neoformans/imunologia , Infecções por HIV/imunologia , Leucócitos Mononucleares/imunologia , Infecções Oportunistas Relacionadas com a AIDS/imunologia , Quimiocina CCL3 , Quimiocina CCL4 , Quimiocina CCL5/biossíntese , Quimiocina CCL5/genética , Quimiocinas CC/genética , Ensaio de Imunoadsorção Enzimática , Regulação da Expressão Gênica , Infecções por HIV/patologia , Humanos , Proteínas Inflamatórias de Macrófagos/biossíntese , Proteínas Inflamatórias de Macrófagos/genética , Receptores CCR5/genética , Receptores CCR5/metabolismo , Receptores de HIV/genética , Receptores de HIV/metabolismo , Ribonucleases/metabolismo
16.
Ann Intern Med ; 132(3): 205-8, 2000 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-10651601

RESUMO

BACKGROUND: Although cryptococcosis has been associated with birds for almost 50 years, point sources for infection have not been identified. OBJECTIVE: To document zoonotic transmission of Cryptococcus neoformans. DESIGN: Case report. SETTING: A home in Boston, Massachusetts. PATIENT: A 72-year-old woman who received a diagnosis of cryptococcal meningitis in November 1998. The patient, who had been taking immunosuppressant drugs since undergoing renal transplantation in 1989, owned a pet cockatoo. MEASUREMENTS: Cryptococcus neoformans was isolated from the feces of the cockatoo. Isolates from excreta and from the patient were compared by using biochemical profiles, monoclonal antibody binding patterns, restriction fragment length polymorphism analysis, and karyotyping. RESULTS: The isolates from the patient and the cockatoo had identical biochemical profiles, the same monoclonal antibody immunofluorescence patterns, and indistinguishable patterns on restriction fragment length polymorphism analysis and karyotyping. CONCLUSIONS: The indistinguishable patient and cockatoo isolates strongly suggest that the patient's infection resulted from exposure to aerosolized cockatoo excreta. Although the incidence of cryptococcal infection due to such exposure is unknown, it may be prudent to advise immunocompromised patients to avoid pet birds and avian excreta.


Assuntos
Animais Domésticos , Aves , Criptococose/transmissão , Hospedeiro Imunocomprometido , Zoonoses , Idoso , Animais , Criptococose/veterinária , Cryptococcus neoformans/classificação , Cryptococcus neoformans/isolamento & purificação , Feminino , Humanos , Transplante de Rim/imunologia , Sorotipagem
17.
Med Mycol ; 38 Suppl 1: 205-13, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-11204147

RESUMO

The incidence of cryptococcosis rose dramatically with the advent of the acquired immune deficiency syndrome (AIDS) epidemic in the early 1980s until the early 1990s. The frequency of cryptococcosis has been declining since mid 1990s in Europe and America due to the development of more effective antiretroviral therapy and prophylactic treatment regimens designed to prevent fungal infections. The disease, however, is still recognized as one of the most common life-threatening opportunistic fungal infections in immunocompromised patients, particularly among those infected with human immunodeficiency virus (HIV). For this reason, research interest in clinical and biological aspects of the disease remains high. In addition to previously embarked areas of research, the cryptococcal research community has taken advantage of the current sequencing technology and initiated genome sequencing of Cryptococcus neoformans var. neoformans. This review includes various areas of research interest ranging from pathobiology, biochemistry and immunology, to genomics.


Assuntos
Criptococose/imunologia , Criptococose/fisiopatologia , Cryptococcus neoformans/genética , Cryptococcus neoformans/patogenicidade , Infecções Oportunistas Relacionadas com a AIDS/microbiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criptococose/epidemiologia , Criptococose/microbiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Virulência
18.
Infect Immun ; 67(9): 4732-6, 1999 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10456924

RESUMO

Penicillium marneffei, a dimorphic fungus endemic in parts of Asia, causes disease in those with impaired cell-mediated immunity, especially persons with AIDS. The histopathology of penicilliosis marneffei features the intracellular infection of macrophages. We studied the interactions between human leukocytes and heat-killed yeast-phase P. marneffei. Monocyte-derived macrophages bound and internalized P. marneffei in the presence of complement-sufficient pooled human serum (PHS). Binding and phagocytosis were still seen if PHS was heat inactivated or omitted altogether. The binding of unopsonized P. marneffei to monocyte-derived macrophages occurred in the absence of divalent cations and was not affected by inhibitors of mannose and beta-glucan receptors or monoclonal antibodies directed against CD14 and CD11/CD18. Binding was profoundly inhibited by wheat germ agglutinin. A vigorous respiratory burst was seen in peripheral blood mononuclear cells (PBMC) stimulated with P. marneffei, regardless of whether the fungi were opsonized. However, tumor necrosis factor alpha (TNF-alpha) release from PBMC stimulated with P. marneffei occurred only if serum was present. These data demonstrate that (i) monocyte-derived macrophages bind and phagocytose P. marneffei even in the absence of opsonization, (ii) binding is divalent cation independent but is inhibited by wheat germ agglutinin, suggesting that the major receptor(s) recognizing P. marneffei is a glycoprotein with exposed N-acetyl-beta-D-glucosaminyl groups, (iii) P. marneffei stimulates the respiratory burst regardless of whether opsonins are present, and (iv) serum factors are required for P. marneffei to stimulate TNF-alpha release. The ability of unopsonized P. marneffei to parasitize mononuclear phagocytes without stimulating the production of TNF-alpha may be critical for the virulence of this intracellular parasite.


Assuntos
Leucócitos/microbiologia , Penicillium/imunologia , Fagocitose/imunologia , Adulto , Células Cultivadas , Humanos , Leucócitos/imunologia , Macrófagos/imunologia , Macrófagos/microbiologia , Receptores Mitogênicos/imunologia , Explosão Respiratória , Fator de Necrose Tumoral alfa/metabolismo
19.
Infect Immun ; 67(2): 885-90, 1999 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9916104

RESUMO

Recently, we demonstrated that human monocyte-derived macrophages (MDM) treated with chloroquine or ammonium chloride had markedly increased antifungal activity against the AIDS-related pathogen Cryptococcus neoformans. Both of these agents raise the lysosomal pH, which suggested that the increased antifungal activity was a function of alkalinizing the phagolysosome. Moreover, there was an inverse correlation between growth of C. neoformans in cell-free media and pH. These data suggested that C. neoformans was well adapted to survive within acidic compartments. To test this hypothesis, we performed studies to determine the pH of human MDM and neutrophil phagosomes containing C. neoformans. Fungi were labeled with the isothiocyanate derivatives of two pH-sensitive probes: fluorescein and 2',7'-difluorofluorescein (Oregon Green). These probes have pKas of 6.4 and 4.7, respectively, allowing sensitive pH detection over a broad range. The phagosomal pH averaged approximately 5 after ingestion of either live or heat-killed fungi and remained relatively constant over time, which suggested that C. neoformans does not actively regulate the pH of its phagosome. The addition of 10 and 100 microM chloroquine resulted in increases in the phagosomal pH from a baseline of 5.1 up to 6.5 and 7.3, respectively. Finally, by immunofluorescence, colocalization of C. neoformans and the MDM lysosomal membrane protein LAMP-1 was demonstrated, establishing that fusion of C. neoformans-laden phagosomes with lysosomal compartments takes place. Thus, unlike many other intracellular pathogens, C. neoformans does not avoid fusion with macrophage lysosomal compartments but rather resides and survives in an acidic phagolysosome.


Assuntos
Cryptococcus neoformans/fisiologia , Macrófagos/microbiologia , Fagossomos/microbiologia , Calibragem , Cloroquina/farmacologia , Fluoresceína-5-Isotiocianato , Humanos , Concentração de Íons de Hidrogênio , Macrófagos/efeitos dos fármacos , Macrófagos/fisiologia , Neutrófilos/microbiologia , Neutrófilos/fisiologia , Fagossomos/efeitos dos fármacos , Fagossomos/fisiologia
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