Fungicidal monoclonal antibody C7 binds to Candida albicans Als3

Abstract

Monoclonal antibody (MAb) C7 reacted with a >200-kDa component from the Candida albicans cell wall identified by matrix-assisted laser desorption ionization-time-of-flight mass spectrometry as Als3. It also bound the recombinant N terminus of Als3. Binding of MAb C7 to Als3 may explain the biological activities exerted by the MAb on C. albicans.

FIG. 1.

Western blots of 10% slab gels loaded with an antigen of >200 kDa purified by electroelution from extracts of C. albicans germ tubes before (lane 1) and after (lanes 2 to 6) deglycosylation. Antigens were stained with silver stain (lanes 1 and 2), MAb C7 (lanes 3 and 4), a polyclonal antibody against Als3 protein (lane 5), and a polyclonal antibody against Als proteins (lane 6). Antigens in lane 4 were further oxidized with sodium meta-periodate. The molecular mass of a standard protein is listed on the left.

FIG. 2.

(A) Dot assay showing the reactivity of polyclonal antisera raised against a peptide with a sequence specific for Als3 and against a peptide with a sequence conserved in all Als proteins. (B) Western blots of 10% slab gels loaded with extracts from E. coli cells expressing the N-terminal end of C. albicans Als3 stained with MAb C7 (lane 1), a rabbit polyclonal anti-Als3 antiserum (lane 2), a rabbit polyclonal anti-Als antiserum (lane 3), and an irrelevant IgM MAb (lane 4), respectively. A recombinant fragment of C. albicans HWP1 cloned in the same plasmid used to clone ALS3 stained with MAb C7 is shown in lane 5. Molecular masses of standard proteins are listed to the left of the gel.