Pollen grains bind to lung alveolar type II cells (A549) via lung surfactant protein A (SP-A). Issue 2 (April 1993)

• Record Type: Journal Article
• Authors: Malhotra, Rajneesh; Haurum, John; Thiel, Steffen; Jensenius, J. -C.; Sim, Robert B.
• Is Part Of: Bioscience reports. Volume 13:Issue 2(1993)
• Page Start: 79
• Page End: 90
• Publication Date: 1993-04
• Subjects: SP-A -- pollen grains -- alveolar type II cells (A549); Molecular biology -- Periodicals; Cytology -- Periodicals; 572.8
• DOI: 10.1007/BF01145960
• Languages: English
• ISSNs: 0144-8463

Abstract

Abstract : Lung surfactant protein A (SP-A) is the most abundant surfactant-associated protein present in the lung. A receptor for SP-A has been shown to be present on A549 alveolar type II cells and on other cell types, including alveolar macrophage. The SP-A receptor on A549 cells has been identified as the collectin receptor, or C1q receptor, which binds several structurally-related ligands. SP-A contains C-type lectin domains, but the role of carbohydrate binding by SP-A in physiological and pathological phenomena is not yet established. In this paper we report the binding of SP-A to pollen from Populus nigra italica (Lombardy Poplar), Poa pratensis (Kentucky blue grass), Secale cerale (cultivated rye) and Ambrosia elatior (short ragweed). Saturable and concentration dependent binding of SP-A to pollen grains was observed. Interaction of SP-A with pollen grains takes place through waterextractable components, in which the major species present, in Lombardy poplar pollen, are 57 kD and 7 kD (glyco)proteins. The binding of SP-A to pollen grains and their aqueous extracts was calcium ion dependent and was inhibited by mannose, and is therefore mediated by the lectin domain. Binding of SP-A to pollen grains was found to mediate adhesion of pollen grains to A549 cells. The results suggest that pollen grains or other carbohydrate-bearing particles (e. g. microorganisms) could potentially interact with different cell types via the collectin receptor (C1q Receptor) in the presence of SP-A.