Effect of serum IgG1 to Cryptococcus neoformans glucuronoxylomannan on murine pulmonary infection
Feldmesser, M.; Casadevall, A.
Journal of Immunology 158(2): 790-799
1997
ISSN/ISBN: 0022-1767 PMID: 8992996 Document Number: 482600
The ability of murine IgG1 monoclonal antibody (mAb) 2H1 to modify pulmonary C. neoformans infection was investigated in intratracheal infection. mAb 2H1 binds C. neoformans glucuronoxylomannan. mAb 2H1 was given to A/JCr mice 24 h before infection. Two C. neoformans strains were studied: ATCC 24067 (serotype D) and 62070 (serotype A). Fungal burden was determined by colony forming units (CFU) 14 days after infection for both strains and at 2 h, 24 h, 48 h, 7 days and 28 days after infection for strain 24067. On day 14, mAb 2H1 treatment reduced CFU in the lung, brain and liver for strain 62070 infection. Minor reductions in lung CFU followed infection with strain 24067 in mAb 2H1-treated mice, despite prolonged survival. It is suggested that the limited ability of mAb 2H1 to reduce lung CFU may reflect rapid phagocytosis of yeast by alveolar macrophages, seen by electron microscopy 2 h after infection, regardless of whether mice had received mAb. Alveolar macrophages phagocytosed and reduced C. neoformans CFU in vitro only in the presence of mAb 2H1. Differences were apparent in phagocytosis and in vitro killing between strains 24067 and 62070. Serum IgG1 modified the course of pulmonary infection in mice by prolonging survival, reducing CFU and reducing tissue glucuronoxylomannan antigen. mAb administration was associated with enhanced granulomatous inflammation, but did not prevent infection or dissemination. It is concluded that despite incomplete protection by serum antibodies against pulmonary infection, the results provide encouragement for continued vaccine development.