FIG 6.

The Crp127 epitope is spatially confined to distinct capsular regions, and binding elicits capsular swelling reactions distinct from those elicited by 18B7. Cryptococcus cells were grown under capsule-inducing conditions and imaged to determine the location of the Crp127 epitope within the enlarged capsule and characterize the capsular reaction patterns elicited by this antibody. (A to D) Cryptococcus strains of serotype A (KN99α and H99) (A), serotype B (R265 and CDCR272) (B), serotype D (B3501 and JEC155) (C), and serotype AD (CBS 950 and ZG287) (D) were labeled for chitin (CFW) (blue) and Crp127 (goat Alexa 647-conjugated anti-mouse IgM μ-chain) (far red), suspended in India ink to visualize the capsule, and imaged using confocal microscopy. Representative images of a single focal plane are shown for each strain. Presented are images merged for transmitted light and Crp127 (left panels) and Crp127 and chitin (right panels). (E to H) Capsule-induced cells of strains KN99α (E), R265 (F), B3501 (G), and CBS 950 (H) were also left untreated (top right panels) or treated with mAb 18B7 (top right panels) or with mAb Crp127 (bottom panels) and imaged using DIC microscopy to observe capsular reaction patterns. Bars, 5 μm.