Fig. 6.
Cells incubated with catalytic Abs have reduced capsule diameter, impaired cellular integrity, and the appearance of reducing glycans in the capsule from polysaccharide hydrolysis. (A) Heat-killed C. neoformans cells were incubated with 18B7, 2H1, a control IgG1 Ab and no Ab for 7 d. Capsule measurements revealed a statistically significant (ordinary one-way ANOVA) decrease in mean capsule diameter when incubated with 18B7 or 2H1 but not in control experiments. Each group contained at least 100 capsule measurements (****P < 0.0001; ns, not significant). (B) Images of heat-killed fungal cells under each Ab condition at both day 0 and day 7. India ink stain allows visualization of capsule diameter. (Scale bar, 10 µm.) (C) Fluorescent microscopy of heat-killed C. neoformans cells incubated with 18B7, 2H1, anti-human IgG, or no antibody (no mAb) and imaged on days 3 and 7. An aminooxy probe was used to visualize the change in capsule architecture after exposure to catalytic Abs over time (green) and capsule shown in red (goat anti-mouse IgG FITC). (Scale bars, 5 µm.)