Functions of cell surface-anchored antigen I/II family and Hsa polypeptides in interactions of Streptococcus gordonii with host receptors
Functions of cell surface-anchored antigen I/II family and Hsa polypeptides in interactions of Streptococcus gordonii with host receptors
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DOI：
10.1128/iai.73.10.6629-6638.2005
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发表时间：
2005-10-01
影响因子：
3.1
通讯作者：
Jenkinson, HF
中科院分区：
文献类型：
--
作者：
Jakubovics, NS;Kerrigan, SW;Jenkinson, HF
戈登链球菌在人类口腔内的多个部位定殖。这种定殖依赖于链球菌粘附素与宿主受体的初始相互作用。结合唾液凝集素糖蛋白（gp 340）和人细胞表面受体的粘附素包括抗原I/II（AgI/II）家族多肽SspA和SspB以及命名为Hsa或GspB的唾液酸结合表面蛋白。本研究确定了AgI/II多肽和Hsa在S. gordonii DL 1（查利斯）与宿主受体的结合。对于缺失sspA和sspB基因的同基因突变体，与表面固定的gp 340的粘附水平降低40%，而单独缺失hsa基因导致细菌细胞与gp 340的粘附抑制>80%。S. gordonii DL 1细胞对gp 340的粘附是唾液酸酶敏感的，证实Hsa在介导唾液酸特异性粘附至gp 340中具有主要作用。相反，S. gp 340对gordonii细胞的抑制作用不受hsa缺失的影响，但通过sspA和sspB基因的缺失而消除。AgI/II多肽基因的缺失对HSA mRNA水平或HSA表面蛋白表达没有可测量的影响，并且HSA的缺失不影响AgI/II多肽的表达。突变体表型分析表明，Hsa和AgI/II蛋白介导了S. gordonii DL 1对人HEp-2上皮细胞的作用。HSA也是促进人血小板粘附到固定化链球菌的主要链球菌细胞表面组分，但HSA和AgI/II多肽在介导链球菌细胞-血小板聚集中起一致作用。结果表明，Hsa指导S. gordonii DLI（查利斯）与固定的gp 340、上皮细胞和血小板。AgI/II多肽指导gp 340介导的聚集，促进血小板聚集所必需的多模式相互作用，并调节S. gordonii-host参与生物生产现象。
Streptococcus gordonii colonizes multiple sites within the human oral cavity. This colonization depends upon the initial interactions of streptococcal adhesins with host receptors. The adhesins that bind salivary agglutinin glycoprotein (gp340) and human cell surface receptors include the antigen I/II (AgI/II) family polypeptides SspA and SspB and a sialic acid-binding surface protein designated Hsa or GspB. In this study we determined the relative functions of the AgI/II polypeptides and Hsa in interactions of S. gordonii DL1 (Challis) with host receptors. For an isogenic mutant with the sspA and sspB genes deleted the levels of adhesion to surface-immobilized gp340 were reduced 40%, while deletion of the hsa gene alone resulted in >80% inhibition of bacterial cell adhesion to gp340. Adhesion of S. gordonii DL1 cells to gp340 was sialidase sensitive, verifying that Hsa has a major role in mediating sialic acid-specific adhesion to gp340. Conversely, aggregation of S. gordonii cells by fluid-phase gp340 was not affected by deletion of hsa but was eliminated by deletion of the sspA and sspB genes. Deletion of the AgI/II polypeptide genes had no measurable effect on hsa mRNA levels or Hsa surface protein expression, and deletion of hsa did not affect AgI/II polypeptide expression. Further analysis of mutant phenotypes showed that the Hsa and AgI/II proteins mediated adhesion of S. gordonii DL1 to human HEp-2 epithelial cells. Hsa was also a principal streptococcal cell surface component promoting adhesion of human platelets to immobilized streptococci, but Hsa and AgI/II polypeptides acted in concert in mediating streptococcal cell-platelet aggregation. The results suggest that Hsa directs primary adhesion events for S. gordonii DLI (Challis) with immobilized gp340, epithelial cells, and platelets. AgI/II polypeptides direct gp340-mediated aggregation, facilitate multimodal interactions necessary for platelet aggregation, and modulate S. gordonii-host engagements into biologically productive phenomena.