Pulmonary surfactant protein A binds to Cryptococcus neoformans without promoting phagocytosis
Walenkamp, Verheul, Scharringa… - European journal of …, 1999 - Wiley Online Library
Walenkamp, Verheul, Scharringa, Hoepelman
European journal of clinical investigation, 1999•Wiley Online LibraryBackground Evidence is accumulating that the alveolar collectin surfactant protein A (SP‐A)
plays an important role in the first line of defence against infiltrating pathogenic micro‐
organisms and viruses. The ability of SP‐A to facilitate the binding and uptake of acapsular
Cryptococcus neoformans by monocyte‐derived macrophages, human alveolar
macrophages, monocytes and polymorphonuclear leucocytes was investigated. Materials
and methods Binding, competition and phagocytosis experiments were performed using a …
plays an important role in the first line of defence against infiltrating pathogenic micro‐
organisms and viruses. The ability of SP‐A to facilitate the binding and uptake of acapsular
Cryptococcus neoformans by monocyte‐derived macrophages, human alveolar
macrophages, monocytes and polymorphonuclear leucocytes was investigated. Materials
and methods Binding, competition and phagocytosis experiments were performed using a …
Background
Evidence is accumulating that the alveolar collectin surfactant protein A (SP‐A) plays an important role in the first line of defence against infiltrating pathogenic micro‐organisms and viruses. The ability of SP‐A to facilitate the binding and uptake of acapsular Cryptococcus neoformans by monocyte‐derived macrophages, human alveolar macrophages, monocytes and polymorphonuclear leucocytes was investigated.
Materials and methods
Binding, competition and phagocytosis experiments were performed using a flow cytometry technique.
Results
SP‐A bound to both the acapsular and the encapsulated form of C. neoformans in a concentration‐dependent manner. SP‐A showed a threefold better binding to the acapsular yeast: this binding was partly calcium dependent and could be inhibited by mannose (ID50 = 3 mmol L−1) and glucose (ID50 = 2.1 mmol L−1) but not by galactose (ID50 = 391 mmol L−1). SP‐A did not function as an opsonin in phagocytosis of acapsular C. neoformans for any of the phagocytes studied.
Conclusion
Our results indicate that SP‐A binds in a concentration‐dependent manner to both encapsulated and acapsular C. neoformans. Despite SP‐A binding to the acapsular C. neoformans, phagocytosis by various phagocytes was not enhanced.
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