Expression of surface hydrophobic proteins by Candida albicans in vivo

Abstract

Candida albicans modulates cell surface hydrophobicity during growth and morphogenesis in vitro. To determine if surface hydrophobicity is expressed during pathogenesis, we generated a polyclonal antiserum against yeast hydrophobic proteins. The antiserum was then used for indirect immunofluorescence analysis of tissues from mice colonized and chronically infected with C. albicans. Results demonstrated that yeast hydrophobic proteins are exposed on fungal cells present in host tissues. The polyclonal antiserum distinguished between hydrophobic and hydrophilic cell surfaces in vitro and gave similar staining patterns and intensities for C. albicans cells in vivo. Of the yeast forms present within tissue lesions, approximately half exhibited moderate to intense immunofluorescence with the antiserum. Immunoblot analysis indicated that antigens recognized by the antiserum are predominantly low-molecular-mass hydrophobic proteins that are expressed by different C. albicans isolates and are expressed regardless of growth temperature. Taken together, the immunofluorescence and immunoblot analyses of antigens indicate that C. albicans displays surface hydrophobic proteins during pathogenesis and these proteins are available for hydrophobic interactions with host tissues. The effect of hydrophobic protein exposure on the virulence of C. albicans is discussed.

Inhibition of Candida albicans attachment to extracellular matrix by antibodies which recognize hydrophobic cell wall proteins

“…Separation of the RCD proteins by hydrophobic interaction chromatography (HIC)-HPLC, and the production of a polyclonal antiserum (designated K-HICF6 pAb) against the hydrophobic HIC-HPLC fractions (6 and 7, HICF6/7) has been previously described [8,22]. Monoclonal antibodies (mAb) to C. albicans hydrophobic proteins were produced in collaboration with the University of Virginia Medical Center Hybridoma Facility [24].…”

“…Monoclonal antibodies (mAb) to C. albicans hydrophobic proteins were produced in collaboration with the University of Virginia Medical Center Hybridoma Facility [24]. A/J or BALB/c mice (maintained in an American Association for the Accreditation of Laboratory Animal Care approved facility) were immunized with hydrophobic proteins from HICF6/7 as previously described [8]. Antiserum reactivity was monitored by Western blot analysis of HICF6/7 proteins.…”

“…The fractions were harvested following focusing and loaded onto an SDS-PAGE slab gel as above. Following electrophoresis, the separated proteins were transferred to nitrocellulose (BA-85, Schleicher and Schuell) membranes as described [8].…”

“…Secondary antibodies were alkaline phosphatase (AP)-conjugated goat Kmouse IgG (1:500) to recognize 6C5 or 5D8, and AP-conjugated goat K-mouse IgM (1:500) for 5F8. Final washes and detection were as described [8]. A mixture of the two secondary antibodies was used for lanes treated with the polyclonal antiserum.…”

“…Hydrophobic proteins were identi¢ed and extracted from the C. albicans cell wall [7]. Previous work in our laboratory demonstrated that these proteins are expressed on the surface of C. albicans cells in vivo [8]. Structural and functional evaluation of individual hydrophobic cell wall proteins would thus provide insight into the speci¢c role of CSH in host-fungal interactions.…”