MAbs can modify the intracellular fate of H. capsulatum var. capsulatum. (A) Effect of MAbs to Hsp60 on H. capsulatum var. capsulatum phagocytosis by J774.16 cells. (B) Blockage of Fc receptors reduced phagocytosis. (C) Blockage of the CD11 receptor decreased phagocytosis in control groups and in the IgG2a groups, although phagocytosis was significantly greater in all the MAb groups than in the controls. (D) Effect of MAbs to Hsp60 on H. capsulatum var. capsulatum killing by J774.16 cells. In panels A to D, the values are the averages of three independent experiments, and the error bars indicate standard deviations. Each experiment was done in quadruplicate. *, P < 0.001 for comparisons between MAbs and controls; **, P < 0.001 for a comparison between MAb 7B6 and the other MAbs to Hsp60. (E to H) Colocalization of H. capsulatum var. capsulatum yeast cells in phagosomes as determined using the FITC-dextran contents of lysosomes. MAbs 11D1 (E), 12D3 (F), and 13B7 (G) induced phagolysosomal fusion within J774.16 cells. In contrast, the rate of fusion with MAb 7B6 (H) was much lower.