Surfactant protein A, but not surfactant protein D, is an opsonin for influenza A virus phagocytosis by rat alveolar macrophages
Surfactant protein A, but not surfactant protein D, is an opsonin for influenza A virus phagocytosis by rat alveolar macrophages
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DOI：
10.1002/eji.1830270413
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发表时间：
1997-04-01
影响因子：
5.4
通讯作者：
vanIwaarden, JFF
中科院分区：
文献类型：
--
作者：
Benne, CA;BenaissaTrouw, B;vanIwaarden, JFF
表面活性蛋白A(SP-A)和表面活性蛋白D(SP-D)均为集合素，均可与甲型流感病毒和肺泡巨噬细胞相互作用。然而，目前尚不清楚SP-A和SP-D能否作为调理素参与肺泡巨噬细胞吞噬甲型流感病毒。在本研究中，我们用流式细胞术研究了SP-A和SP-D对异硫氰酸荧光素(FITC)标记的甲型流感病毒(H3N_2)大鼠肺泡巨噬细胞吞噬功能的调节作用。SP-A以剂量依赖的方式增强病毒与巨噬细胞的结合，在SP-A浓度为60微克/毫升时达到最大，在有SP-A的情况下，甲型流感病毒与肺泡巨噬细胞的结合比不含SP-A的对照组增加近3倍。使用胞外猝灭染料台盼蓝可以猝灭一半的细胞相关荧光。这些结果表明，SP-A介导FITC标记的甲型流感病毒由肺泡巨噬细胞内化。用N-糖苷酶F去除SP-A的糖基或用神经氨酸酶裂解SP-A的唾液酸残基，均不能增强肺泡巨噬细胞对FITC标记的甲型流感病毒的吞噬作用。甘露聚糖是一种已知与SP-A的糖结合域结合的甘露糖多糖，不影响SP-A介导的肺泡巨噬细胞吞噬FITC标记的流感病毒。相反，在所测试的SP-D浓度下，SP-D既不能增强FITC标记的甲型流感病毒与肺泡巨噬细胞的结合，也不会影响SP-A对FITC标记的甲型流感病毒(H3N2)的调理活性。结论：SP-A通过其唾液酸残基在肺泡巨噬细胞吞噬甲型流感病毒的过程中发挥调理作用。
Surfactant protein A (SP-A) and surfactant protein D (SP-D) are collectins, and both proteins were shown to interact with influenza A virus and alveolar macrophages. However, it is not known whether SP-A and SP-D can serve as opsonins for the phagocytosis of influenza A virus by alveolar macrophages. In the present study, we investigated the opsonic activities of SP-A and SP-D for phagocytosis of fluorescein isothiocyanate (FITC)-labeled influenza A (H3N2) virus by rat alveolar macrophages using flow cytometry. SP-A enhanced the association of the virus with macrophages in a dose-dependent manner, reaching a maximum at an SP-A concentration of 60 mu g/ml. An approximate threefold increase in association of influenza A virus with alveolar macrophages in the presence of SP-A over control incubations which contained no SP-A was observed. Half of the total cell-associated fluorescence could be quenched as demonstrated using the extracellular quenching dye trypan blue. These results indicate that SP-A mediates internalization of FITC-labeled influenza A (H3N2) virus by alveolar macrophages. Removal of the carbohydrate moiety of SP-A by N-glycosidase F treatment or cleavage of its sialic acid residues by neuraminidase abolished the enhancement of the phagocytosis of FITC-labeled influenza A virus by alveolar macrophages. Mannan, a mannose homopolysaccharide known to bind to the carbohydrate-binding domain of SP-A, did not affect the SP-A-mediated phagocytosis of FITC-labeled influenza by alveolar macrophages. In contrast, SP-D neither enhanced the association of FITC-labeled influenza A virus with alveolar macrophages nor affected the opsonic activity of SP-A for FITC-labeled influenza A (H3N2) virus at the SP-D concentrations tested. It is concluded that SP-A acts via its sialic acid residues as an opsonin in the phagocytosis of influenza A virus by alveolar macrophages.