Fab fragments from a monoclonal antibody against a germ tube mannoprotein block the yeast-to-mycelium transition in Candida albicans.

ABSTRACT Antibodies are believed to play a role in the protection against Candida albicans infections by a number of mechanisms, including the inhibition of adhesion or germ tube formation, opsonization, neutralization of virulence-related enzymes, and direct candidacidal activity. Although some of these biological activities have been demonstrated individually in monoclonal antibodies (MAbs), it is not clear if all these anti-C. albicans activities can be displayed by a single antibody. In this report, we characterized a monoclonal antibody raised against the main target of salivary secretory immunoglobulin A in the cell wall of C. albicans, which exerts three anti-C. albicans activities: (i) inhibition of adherence to HEp-2 cells, (ii) inhibition of germination, and (iii) direct candidacidal activity. MAb C7 reacted with a proteinic epitope from a mannoprotein with a molecular mass of >200 kDa predominantly expressed on the C. albicans germ tube cell wall surface as well as with a number of antigens from Candida lusitaniae, Cryptococcus neoformans, Aspergillus fumigatus, and Scedosporium prolificans. MAb C7 caused a 31.1% inhibition in the adhesion of C. albicans to HEp-2 monolayers and a 55.3% inhibition in the adhesion of C. albicans to buccal epithelial cells, produced a 38.5% decrease in the filamentation of C. albicans, and exhibited a potent fungicidal effect against C. albicans, C. lusitaniae, Cryptococcus neoformans, A. fumigatus, and S. prolificans, showing reductions in fungal growth ranging from 34.2 to 88.7%. The fungicidal activity showed by MAb C7 seems to be related to that reported by antibodies mimicking the activity of a killer toxin produced by the yeast Pichia anomala, since one of these MAbs also reacted with the C. albicans mannoprotein with a molecular mass of >200 kDa. Results presented in this study support the concept of a family of microbicidal antibodies that could be useful in the treatment of a wide range of microbial infections when used alone or in combination with current antimicrobial agents.

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New Monoclonal Antibody Specific for Candida albicans Germ Tube

Journal of Clinical Microbiology ◽

10.1128/jcm.38.1.61-67.2000 ◽

2000 ◽

Vol 38 (1) ◽

pp. 61-67

Author(s):

Agnes Marot-Leblond ◽

Linda Grimaud ◽

Sandrine Nail ◽

Sandrine Bouterige ◽

Veronique Apaire-Marchais ◽

...

Keyword(s):

Monoclonal Antibody ◽

Cell Wall ◽

Candida Albicans ◽

Germ Tube ◽

Pathogenic Fungus ◽

Gel Filtration ◽

Wall Surface ◽

Closely Related Species ◽

Highly Hydrophobic ◽

Protein Moiety

ABSTRACT Hydrophobic components of the germ tube of the dimorphic pathogenic fungus Candida albicans were used as immunogens to prepare monoclonal antibodies (MAbs). Among the resulting MAbs, one (MAb 16B1-F10) was shown by indirect immunofluorescence to be specific to the surface of the mycelium phase of the C. albicans and C. stellatoidea species. No labeling of any other genera and Candida species tested was observed, including C. dubliniensis , a newly described species which has many phenotypic similarities to C. albicans . This phase-specific epitope resides on a protein moiety. The molecular mass of the antigen released by Zymolyase digestion was determined by gel filtration and ranges from 25 to 166 kDa. The antigen was also shown to be highly hydrophobic. This anti- C. albicans cell wall surface-specific MAb may be a good candidate for use in tests for the rapid differentiation of the two closely related species C. albicans and C. dubliniensis .

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Faculty Opinions recommendation of The interaction of human dendritic cells with yeast and germ-tube forms of Candida albicans leads to efficient fungal processing, dendritic cell maturation, and acquisition of a Th1 response-promoting function.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1016239.199628 ◽

2003 ◽

Author(s):

Emanuela Handman

Keyword(s):

Dendritic Cells ◽

Candida Albicans ◽

Dendritic Cell ◽

Germ Tube ◽

Dendritic Cell Maturation ◽

Cell Maturation ◽

Th1 Response ◽

Human Dendritic Cells

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Comparison of the Murex, Candida albicans CA50 test with germ tube production for identification of C. albicans

Diagnostic Microbiology and Infectious Disease ◽

10.1016/0732-8893(95)00199-9 ◽

1996 ◽

Vol 24 (1) ◽

pp. 31-35 ◽

Cited By ~ 8

Author(s):

JoAnn P. Fenn ◽

Helene Segal ◽

Lisa Blevins ◽

Shawn Fawson ◽

Patty Newcomb-Gayman ◽

...

Keyword(s):

Candida Albicans ◽

Germ Tube ◽

Tube Production

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Indirect immunofluorescence assay for antibody to germ tube of Candida albicans--a new diagnostic test.

Journal of Clinical Pathology ◽

10.1136/jcp.29.11.1007 ◽

1976 ◽

Vol 29 (11) ◽

pp. 1007-1010 ◽

Cited By ~ 13

Author(s):

Y M Ho ◽

M H Ng ◽

C H Teoh-Chan ◽

P C Yue ◽

C T Huang

Keyword(s):

Candida Albicans ◽

Diagnostic Test ◽

Indirect Immunofluorescence ◽

Germ Tube ◽

Immunofluorescence Assay ◽

Indirect Immunofluorescence Assay

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A novel type of cell death of lymphocytes induced by a monoclonal antibody without participation of complement.

Journal of Experimental Medicine ◽

10.1084/jem.181.6.2007 ◽

1995 ◽

Vol 181 (6) ◽

pp. 2007-2015 ◽

Cited By ~ 27

Author(s):

S Matsuoka ◽

Y Asano ◽

K Sano ◽

H Kishimoto ◽

I Yamashita ◽

...

Keyword(s):

Monoclonal Antibody ◽

Cell Death ◽

T Cell ◽

B Cells ◽

Interleukin 2 ◽

Cytolytic Activity ◽

Target Cells ◽

T And B Cells ◽

Fab Fragments ◽

T Cell Clone

A monoclonal antibody, RE2, raised by immunizing a rat with cell lysate of a mouse T cell clone, was found to directly kill interleukin 2-dependent T cell clones without participation of serum complement. Fab fragments of RE2 had no cytolytic activity, while the cross-linking of Fab fragments with anti-rat immunoglobulin reconstituted the cytotoxicity. The cytotoxicity was temperature dependent: the antibody could kill target cells at 37 degrees C but not at 0 degrees C. Sodium azide, ethylenediaminetetraacetic acid, and forskolin did not affect the cytolytic activity of RE2, while the treatment of target cells with cytochalasin B and D completely blocked the activity. This suggested that the cell death involves a cytoskeleton-dependent active process. Giant holes on the cell membrane were formed within 5 minutes after the treatment with RE2, as observed by scanning electron microscopy. There was no indication of DNA fragmentation nor swelling of mitochondria during the cytolysis, suggesting that the cell death is neither apoptosis nor typical necrosis. The antibody also killed T cell lymphomas and T and B cell hybridomas only when these cells were preactivated with concanavalin A, lipopolysaccharide, or phorbol myristate acetate. Preactivated peripheral T and B cells were sensitive to the cytotoxicity of RE2, while resting T and B cells were insensitive. These results provide evidence for a novel pathway of cell death of activated lymphocytes by membrane excitation.

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CAP1, an Adenylate Cyclase-Associated Protein Gene, Regulates Bud-Hypha Transitions, Filamentous Growth, and Cyclic AMP Levels and Is Required for Virulence of Candida albicans

Journal of Bacteriology ◽

10.1128/jb.183.10.3211-3223.2001 ◽

2001 ◽

Vol 183 (10) ◽

pp. 3211-3223 ◽

Cited By ~ 118

Author(s):

Yong-Sun Bahn ◽

Paula Sundstrom

Keyword(s):

Candida Albicans ◽

Cyclic Amp ◽

Adenylate Cyclase ◽

Germ Tube ◽

Filamentous Growth ◽

Tube Formation ◽

Camp Signaling ◽

Solid Media ◽

Opportunistic Fungal Pathogen ◽

Camp Levels

ABSTRACT In response to a wide variety of environmental stimuli, the opportunistic fungal pathogen Candida albicans exits the budding cycle, producing germ tubes and hyphae concomitant with expression of virulence genes, such as that encoding hyphal wall protein 1 (HWP1). Biochemical studies implicate cyclic AMP (cAMP) increases in promoting bud-hypha transitions, but genetic evidence relating genes that control cAMP levels to bud-hypha transitions has not been reported. Adenylate cyclase-associated proteins (CAPs) of nonpathogenic fungi interact with Ras and adenylate cyclase to increase cAMP levels under specific environmental conditions. To initiate studies on the relationship between cAMP signaling and bud-hypha transitions in C. albicans, we identified, cloned, characterized, and disrupted the C. albicans CAP1 gene. C. albicans strains with inactivated CAP1 budded in conditions that led to germ tube formation in isogenic strains withCAP1. The addition of 10 mM cAMP and dibutyryl cAMP promoted bud-hypha transitions and filamentous growth in thecap1/cap1 mutant in liquid and solid media, respectively, showing clearly that cAMP promotes hypha formation in C. albicans. Increases in cytoplasmic cAMP preceding germ tube emergence in strains having CAP1 were markedly diminished in the budding cap1/cap1 mutant. C. albicans strains with deletions of both alleles ofCAP1 were avirulent in a mouse model of systemic candidiasis. The avirulence of a germ tube-deficientcap1/cap1 mutant coupled with the role of Cap1 in regulating cAMP levels shows that the Cap1-mediated cAMP signaling pathway is required for bud-hypha transitions, filamentous growth, and the pathogenesis of candidiasis.

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