As described above, complement and antibody are required for efficient phagocytosis of C. neoformans in vitro, with potential compensation when one opsonin is missing or impaired. In agreement with this the reduced complement mediated phagocytosis caused by increased cryptococcal capsular size is compensated with increase in antibody mediated phagocytosis, demonstrated with C5 deficient mice which have an increased antibody response (Dromer et al., 1989; Zaragoza et al., 2003).