We previously reported that the immunoglobulin M (IgM) monoclonal antibody (MAb) B6.1 protects @entity19 against @entity6831 , whereas the IgM MAb B6 does not. Both MAbs are specific for an adhesin fraction isolated from the cell surface of @entity5132 , but their epitope specificities differ. In the present study, we examined the surface locations of both epitopes and obtained structural information regarding the B6.1 epitope. Immunofluorescence confocal microscopic analysis of @entity5132 @entity375 forms showed that epitope B6.1 is displayed rather homogeneously over the entire cell surface, whereas epitope B6 appears to have a patchy distribution. Both antibodies were essentially nonreactive with the surfaces of mycelial forms of the fungus, indicating that neither epitope is expressed on the surfaces of these forms. For isolation of the B6.1 epitope, the adhesin fraction consisting of cell surface phosphomannan was subjected to mildly acidic (10 mM @entity5828 ) hydrolysis and was fractionated into acid-labile and acid-stable portions by size exclusion chromatography. Antibody blocking experiments showed that the B6.1 epitope is an acid-labile moiety of the phosphomannan and that the B6 epitope is located in the acid-stable fraction. The B6 epitope appeared to be mannan because it was stable to heat (boiling) and protease treatments but was destroyed by alpha-mannosidase digestion. The B6.1 epitope eluted from the size exclusion column in two fractions. Mass spectroscopic analyses showed that one fraction contained material with the size of a @entity60934 and that the other was a mixture of @entity60934 - and @entity70064 -size substances. Dose response inhibition tests of the fractions indicated that the B6.1 epitope is associated with the @entity60934 . Nuclear magnetic resonance (NMR) spectroscopic analysis of the epitope yielded data consistent with a beta-(1-->2)-linked @entity60934 . The fine structure of the B6 epitope is under investigation. Information derived from these investigations will be useful both in understanding protective versus nonprotective antibody responses to @entity5132 and in improving anti-Candida vaccine formulations.

Biochemical characterization of XXXX epitopes that can elicit protective and nonprotective antibodies.

@entity19 :: ('10090', 'Species') :: ['mice'] @entity60934 :: ('MESH:C023872', 'Chemical') :: ['mannotriose'] @entity6831 :: ('MESH:D004673', 'Disease') :: ['disseminated candidiasis'] @entity5132 :: ('5476', 'Species') :: ['Candida albicans', 'C. albicans'] @entity5828 :: ('CHEBI:17883', 'Chemical') :: ['HCl'] @entity375 :: ('4932', 'Species') :: ['yeast'] @entity70064 :: ('MESH:C039922', 'Chemical') :: ['mannotetraose']
@entity5132 :: (5476,Species) :: ['Candida albicans']
