scholarly journals The Monoclonal Antibody against the Major Diagnostic Antigen of Paracoccidioides brasiliensis Mediates Immune Protection in Infected BALB/c Mice Challenged Intratracheally with the Fungus

2008 ◽  
Vol 76 (7) ◽  
pp. 3321-3328 ◽  
Author(s):  
R. Buissa-Filho ◽  
R. Puccia ◽  
A. F. Marques ◽  
F. A. Pinto ◽  
J. E. Muñoz ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Vaccine Development ◽  
Paracoccidioides Brasiliensis ◽  
Passive Immunization ◽  
Yeast Cells ◽  
No Production ◽  
Fungal Burden ◽  
Diagnostic Antigen

ABSTRACT The protective role of specific antibodies against Paracoccidioides brasiliensis is controversial. In the present study, we analyzed the effects of monoclonal antibodies on the major diagnostic antigen (gp43) using in vitro and in vivo P. brasiliensis infection models. The passive administration of some monoclonal antibodies (MAbs) before and after intratracheal or intravenous infections led to a reduced fungal burden and decreased pulmonary inflammation. The protection mediated by MAb 3E, the most efficient MAb in the reduction of fungal burden, was associated with the enhanced phagocytosis of P. brasiliensis yeast cells by J774.16, MH-S, or primary macrophages. The ingestion of opsonized yeast cells led to an increase in NO production by macrophages. Passive immunization with MAb 3E induced enhanced levels of gamma interferon in the lungs of infected mice. The reactivity of MAb 3E against a panel of gp43-derived peptides suggested that the sequence NHVRIPIGWAV contains the binding epitope. The present work shows that some but not all MAbs against gp43 can reduce the fungal burden and identifies a new peptide candidate for vaccine development.

scholarly journals Detection of Melanin-Like Pigments in the Dimorphic Fungal Pathogen Paracoccidioides brasiliensis In Vitro and during Infection

2001 ◽  
Vol 69 (9) ◽  
pp. 5760-5767 ◽  
Author(s):  
Beatriz L. Gómez ◽  
Joshua D. Nosanchuk ◽  
Soraya Dı́ez ◽  
Sirida Youngchim ◽  
Philip Aisen ◽  
...  
Keyword(s):  
Fungal Pathogen ◽  
Proteolytic Enzymes ◽  
Paracoccidioides Brasiliensis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Yeast Cells ◽  
Resonance Spectroscopy ◽  
Microbial Infections ◽  
Melanin Binding

ABSTRACT Melanins are implicated in the pathogenesis of several human diseases, including some microbial infections. In this study, we analyzed whether the conidia and the yeasts of the thermally dimorphic fungal pathogen Paracoccidioides brasiliensis produce melanin or melanin-like compounds in vitro and during infection. Growth of P. brasiliensis mycelia on water agar alone produced pigmented conidia, and growth of yeasts in minimal medium withl-3,4-dihydroxyphenylalanine (l-DOPA) produced pigmented cells. Digestion of the pigmented conidia and yeasts with proteolytic enzymes, denaturant, and hot concentrated acid yielded dark particles that were the same size and shape as their propagules. Immunofluorescence analysis demonstrated reactivity of a melanin-binding monoclonal antibody (MAb) with the pigmented conidia, yeasts, and particles. Electron spin resonance spectroscopy identified the yeast-derived particles produced in vitro when P. brasiliensis was grown in l-DOPA medium as a melanin-like compound. Nonreducing polyacrylamide gel electrophoresis of cytoplasmic yeast extract revealed a protein that catalyzed melanin synthesis from l-DOPA. The melanin binding MAb reacted with yeast cells in tissue from mice infected with P. brasiliensis. Finally digestion of infected tissue liberated particles reactive to the melanin binding MAb that had the typical morphology of P. brasiliensis yeasts. These data strongly suggest that P. brasiliensis propagules, both conidia and yeast cells, can produce melanin or melanin-like compounds in vitro and in vivo. Based on what is known about the function of melanin in the virulence of other fungi, this pigment may play a role in the pathogenesis of paracoccidioidomycosis.

scholarly journals Efficacy of Opsonic and Nonopsonic Serotype 3 Pneumococcal Capsular Polysaccharide-Specific Monoclonal Antibodies against Intranasal Challenge with Streptococcus pneumoniae in Mice

2009 ◽  
Vol 77 (4) ◽  
pp. 1502-1513 ◽  
Author(s):  
Haijun Tian ◽  
Sarah Weber ◽  
Peter Thorkildson ◽  
Thomas R. Kozel ◽  
Liise-anne Pirofski
Keyword(s):  
Monoclonal Antibodies ◽  
Streptococcus Pneumoniae ◽  
Capsular Polysaccharide ◽  
Passive Immunization ◽  
Immunodeficient Mice ◽  
Pneumococcal Strain ◽  
J774 Cells ◽  
Complement Component 3

ABSTRACT Serotype-specific antibodies to pneumococcal capsular polysaccharide (PPS) are a critical component of vaccine-mediated immunity to Streptococcus pneumoniae. In this study, we investigated the in vitro opsonophagocytic activities of three PPS-specific mouse immunoglobulin G1 monoclonal antibodies (MAbs), 1E2, 5F6, and 7A9, and determined their in vivo efficacies against intranasal challenge with WU2, a serotype 3 pneumococcal strain, in normal and immunodeficient mice. The MAbs had different in vitro activities in a pneumococcal killing assay: 7A9 enhanced killing by mouse neutrophils and J774 cells in the presence of a complement source, whereas 5F6 promoted killing in the absence, but not the presence, of complement, and 1E2 did not promote killing under any conditions. Nonetheless, all three MAbs protected normal and complement component 3-deficient mice from a lethal intranasal challenge with WU2 in passive-immunization experiments in which 10 μg of the MAbs were administered intraperitoneally before intranasal challenge. In contrast, only 1E2 protected Fcγ receptor IIB knockout (FcγRIIB KO) mice and mice that were depleted of neutrophils with the MAb RB6, whereas 7A9 and 5F6 required neutrophils and FcγRIIB to mediate protection. Conversely, 7A9 and 5F6 protected FcγR KO mice, but 1E2 did not. Hence, the efficacy of 1E2 required an activating FcγR(s), whereas 5F6 and 7A9 required the inhibitory FcγR (FcγRIIB). Taken together, our data demonstrate that both MAbs that do and do not promote pneumococcal killing in vitro can mediate protection in vivo, although their efficacies depend on different host receptors and/or components.

scholarly journals The P. falciparum CSP repeat region contains three distinct epitopes required for protection by antibodies in vivo

2021 ◽  
Vol 17 (11) ◽  
pp. e1010042
Author(s):  
Yevel Flores-Garcia ◽  
Lawrence T. Wang ◽  
Minah Park ◽  
Beejan Asady ◽  
Azza H. Idris ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Monoclonal Antibodies ◽  
Malaria Infection ◽  
Vaccine Development ◽  
Circumsporozoite Protein ◽  
Repeat Region ◽  
Human Mabs ◽  
Necessary And Sufficient

Rare and potent monoclonal antibodies (mAbs) against the Plasmodium falciparum (Pf) circumsporozoite protein (CSP) on infective sporozoites (SPZ) preferentially bind the PfCSP junctional tetrapeptide NPDP or NVDP minor repeats while cross-reacting with NANP major repeats in vitro. The extent to which each of these epitopes is required for protection in vivo is unknown. Here, we assessed whether junction-, minor repeat- and major repeat-preferring human mAbs (CIS43, L9 and 317 respectively) bound and protected against in vivo challenge with transgenic P. berghei (Pb) SPZ expressing either PfCSP with the junction and minor repeats knocked out (KO), or PbCSP with the junction and minor repeats knocked in (KI). In vivo protection studies showed that the junction and minor repeats are necessary and sufficient for CIS43 and L9 to neutralize KO and KI SPZ, respectively. In contrast, 317 required major repeats for in vivo protection. These data establish that human mAbs can prevent malaria infection by targeting three different protective epitopes (NPDP, NVDP, NANP) in the PfCSP repeat region. This report will inform vaccine development and the use of mAbs to passively prevent malaria.

scholarly journals Passive Immunization with Melanin-Binding Monoclonal Antibodies Prolongs Survival of Mice with Lethal Cryptococcus neoformans Infection

2001 ◽  
Vol 69 (5) ◽  
pp. 3410-3412 ◽  
Author(s):  
Ángel L. Rosas ◽  
Joshua D. Nosanchuk ◽  
Arturo Casadevall
Keyword(s):  
Growth Rate ◽  
Monoclonal Antibodies ◽  
Cryptococcus Neoformans ◽  
Passive Immunization ◽  
Fungal Burden ◽  
Melanin Binding

ABSTRACT Passive immunization with monoclonal antibodies (MAbs) to melanin prolonged the survival of and reduced the fungal burden inCryptococcus neoformans-infected mice in comparison to controls. MAbs to melanin reduced the growth rate of in vitro-melanizedC. neoformans cells, suggesting a new mechanism of antibody-mediated protection.

scholarly journals Characterization of gp70 and Anti-gp70 Monoclonal Antibodies in Paracoccidioides brasiliensis Pathogenesis

2003 ◽  
Vol 71 (11) ◽  
pp. 6534-6542 ◽  
Author(s):  
Daniela de Mattos Grosso ◽  
Sandro Rogério de Almeida ◽  
Mario Mariano ◽  
Jose Daniel Lopes
Keyword(s):  
Monoclonal Antibodies ◽  
Culture Supernatant ◽  
Paracoccidioides Brasiliensis ◽  
Passive Immunization ◽  
Peritoneal Macrophages ◽  
Surface Glycoprotein ◽  
Cell Surface Glycoprotein ◽  
A Cell ◽  
Mannose Receptors

ABSTRACT Paracoccidioidomycosis (PCM) is a systemic granulomatous mycosis whose agent is Paracoccidioides brasiliensis. In the culture supernatant, the fungus expresses glycoproteins of from 13 to 148 kDa. A cell surface glycoprotein of 43 kDa is the major antigenic component of P. brasiliensis. Another expressed glycoprotein, gp70, is recognized by 96% of sera from PCM patients and is able to induce lymphoproliferation. Since, little is known about this glycoprotein, we produced monoclonal antibodies (MAbs) against gp70 to isolate the molecule from total fungus extracts and to investigate its possible role in the pathogenesis of PCM. Using these MAbs, it was observed by confocal microscopy that gp70 is located mainly in the intracellular compartment of the fungus, although it was also detected in the culture supernatant. Based on observations showing that gp43 has a down-regulatory effect on mouse peritoneal macrophages, we tested the effects of gp70 on their phagocytic ability. Purified gp70 was able to inhibit the activity of macrophages through the mannose receptors and also through the Fc receptors; the latter effect was not observed with gp43. gp70 inhibits NO and H2O2 liberation by peritoneal macrophages in vitro, as does gp43. Results obtained with gp43 led us to hypothesize that gp70 could act as an escape mechanism for fungal establishment in primary infections. To corroborate this hypothesis, we analyzed the effect of passive immunization of mice during infection with P. brasiliensis using anti-gp70 MAbs. This treatment almost completely abolished granuloma formation in the lungs, suggesting that the protein facilitates fungal establishment and progression of lesions in primary infection.

Paracoccidioides brasiliensis 14-3-3 protein is important for virulence in a murine model

2018 ◽  
Vol 57 (7) ◽  
pp. 900-904
Author(s):  
Caroline Maria Marcos ◽  
Haroldo Cesar de Oliveira ◽  
Patricia Akemi Assato ◽  
Cleverton Roberto de Andrade ◽  
Ana Marisa Fusco-Almeida ◽  
...  
Keyword(s):  
Virulence Factor ◽  
Murine Model ◽  
Pulmonary Infection ◽  
Paracoccidioides Brasiliensis ◽  
Yeast Cells ◽  
Fungal Burden ◽  
Important Virulence Factor

AbstractThe Paracoccidioides brasiliensis strain downregulated the expression of adhesin Pb14-3-3 (Pb14-3-3 aRNA) was evaluated in a murine model of paracoccidioidomycosis (PCM). Pb14-3-3 aRNA displays attenuated virulence and triggered the formation of fewer granulomas by lowering the fungal burden in the lungs. Additionally, the Pb14-3-3 aRNA showed more elongated yeast cells and less ability to induce pneumocytes apoptosis in vitro. Our results show that 14-3-3 is an important virulence factor in P. brasiliensis-induced pulmonary infection.

scholarly journals Morphological Transition of Paracoccidioides brasiliensis Conidia to Yeast Cells: In Vivo Inhibition in Females

1998 ◽  
Vol 66 (11) ◽  
pp. 5587-5591 ◽  
Author(s):  
Beatriz H. Aristizabal ◽  
Karl V. Clemons ◽  
David A. Stevens ◽  
Angela Restrepo
Keyword(s):  
Bronchoalveolar Lavage ◽  
Paracoccidioides Brasiliensis ◽  
Natural Infection ◽  
Yeast Cells ◽  
Morphological Transition ◽  
Male Mice ◽  
Female Hormones

ABSTRACT Clinical paracoccidioidomycosis is 13 times more common in men than in women. Estrogen inhibits the transition of mycelia or conidia (the saprophytic form of Paracoccidoides brasiliensis) to yeasts (the parasitic form) in vitro. Here, we show that, in male mice that were infected intranasally (mimicking natural infection) the transition of conidia in bronchoalveolar lavage fluids to intermediate forms and yeasts occurred over 24 to 96 h; CFU and yeasts (shown by histopathology) increased subsequently. In females, transition did not occur and infection cleared. These events in vivo are consistent with epidemiological and in vitro observations, suggesting that female hormones block transition and are responsible for resistance.

scholarly journals Mucosal Antibodies: Defending Epithelial Barriers against HIV-1 Invasion

Vaccines ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 194 ◽  
Author(s):  
Ruth M. Ruprecht ◽  
Bishal Marasini ◽  
Rajesh Thippeshappa
Keyword(s):  
Vaccine Development ◽  
Passive Immunization ◽  
Protective Mechanism ◽  
Pathogen Invasion ◽  
Epithelial Barriers ◽  
Immune Exclusion ◽  
Anti Hiv ◽  
Hiv 1

The power of mucosal anti-HIV-1 envelope immunoglobulins (Igs) to block virus transmission is underappreciated. We used passive immunization, a classical tool to unequivocally prove whether antibodies are protective. We mucosally instilled recombinant neutralizing monoclonal antibodies (nmAbs) of different Ig classes in rhesus macaques (RMs) followed by mucosal simian–human immunodeficiency virus (SHIV) challenge. We gave anti-HIV-1 IgM, IgG, and dimeric IgA (dIgA) versions of the same human nmAb, HGN194 that targets the conserved V3 loop crown. Surprisingly, dIgA1 with its wide-open, flat hinge protected 83% of the RMs against intrarectal R5-tropic SHIV-1157ipEL-p challenge, whereas dIgA2, with its narrow hinge, only protected 17% of the animals—despite identical epitope specificities and in vitro neutralization curves of the two dIgA isotypes (Watkins et al., AIDS 2013 27(9):F13-20). These data imply that factors in addition to neutralization determine in vivo protection. We propose that this underlying protective mechanism is immune exclusion, which involves large nmAb/virion aggregates that prevent virus penetration of mucosal barriers. Future studies need to find biomarkers that predict effective immune exclusion in vivo. Vaccine development strategies against HIV-1 and/or other mucosally transmissible pathogens should include induction of strong mucosal Abs of different Ig classes to defend epithelial barriers against pathogen invasion.

scholarly journals β2 Integrin-Mediated Susceptibility to Paracoccidioides brasiliensis Experimental Infection in Mice

2021 ◽  
Vol 11 ◽  
Author(s):  
Stephan Alberto Machado de Oliveira ◽  
Janayna Nunes Reis ◽  
Elisa Catão ◽  
Andre Correa Amaral ◽  
Ana Camila Oliveira Souza ◽  
...  
Keyword(s):  
Paracoccidioides Brasiliensis ◽  
Serum Antibody ◽  
Surface Proteins ◽  
Yeast Cells ◽  
Fungal Burden ◽  
Β2 Integrin ◽  
Fungal Load ◽  
Protective Environment ◽  
Migration Capacity

The earliest interaction between macrophages and Paracoccidioides brasiliensis is particularly important in paracoccidioidomycosis (PCM) progression, and surface proteins play a central role in this process. The present study investigated the contribution of β2 integrin in P. brasiliensis-macrophage interaction and PCM progression. We infected β2-low expression (CD18low) and wild type (WT) mice with P. brasiliensis 18. Disease progression was evaluated for fungal burden, lung granulomatous lesions, nitrate levels, and serum antibody production. Besides, the in vitro capacity of macrophages to internalize and kill fungal yeasts was investigated. Our results revealed that CD18low mice infected with Pb18 survived during the time analyzed; their lungs showed fewer granulomas, a lower fungal load, lower levels of nitrate, and production of high levels of IgG1 in comparison to WT animals. Our results revealed that in vitro macrophages from CD18low mice slowly internalized yeast cells, showing a lower fungal burden compared to WT cells. The migration capacity of macrophages was compromised and showed a higher intensity in the lysosome signal when compared with WT mice. Our data suggest that β2 integrins play an important role in fungal survival inside macrophages, and once phagocytosed, the macrophage may serve as a protective environment for P. brasiliensis.

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