Binding of Unopsonized Cryptococcus neoformans by Human Bronchoalveolar Macrophages: Inhibition by a Large-Molecular-Size Serum Component
- 1 October 1992
- journal article
- research article
- Published by Oxford University Press (OUP) in The Journal of Infectious Diseases
- Vol. 166 (4) , 866-873
- https://doi.org/10.1093/infdis/166.4.866
Abstract
Infection with Cryptococcus neoformans usually begins after inhalation of airborne organisms. Since levels of opsonins in the alveolar space may be low, the ability of human bronchoalveolar macrophages to bind C. neoformans in the presence and absence of opsonins was studied. Bronchoalveolar macrophages bound unopsonized C. neoformans. Surprisingly, component(s) in pooled human serum (PHS) inhibited binding, as evidenced by 26% and 71% inhibition of binding when 20% PHS and heat-inactivated PHS (HI-PHS), respectively, were added to the system. Separation of PHS by molecular size revealed that the inhibitory component had an apparent molecular weight < 106 and was inhibitory at nanomolar concentrations. PHS stimulated and HI-PHS had no effect on binding of acapsular C. neoformans and zymosan particles to bronchoalveolar macrophages. These data demonstrate that bronchoalveolar macrophages can bind unopsonized, encapsulated C. neoformans, but that serum component(s) inhibits binding.Keywords
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