McGee D J, Chen G C, Rest R F
Department of Microbiology and Immunology, MCP-Hahnemann School of Medicine, Allegheny University of the Health Sciences, Philadelphia, Pennsylvania 19102, USA.
Infect Immun. 1996 Oct;64(10):4129-36. doi: 10.1128/iai.64.10.4129-4136.1996.
Sialyltransferase (Stase) in Neisseria gonorrhoeae organisms (gonococci [GC]) transfers sialic acid (N-acetylneuraminic acid [NANA]) from cytidine 5'-monophospho-N-acetylneuraminic acid (CMP-NANA) mainly to the terminal galactose (Gal) residue in the Gal beta-1,4 N-acetylglucosamine (Gal-GlcNAc)-R lipooligosaccharide (LOS) structure. Sialylated GC resist killing by normal human serum, sometimes show reduced invasion of epithelial cells, and have reduced adhesion to and stimulation of human neutrophils. We questioned whether Stase itself modulates the interactions of GC with human epithelial cells and neutrophils in the absence of exogenous CMP-NANA. To that end, we treated strain F62 with ethyl methanesulfonate and grew approximately 175,000 colonies on CMP-NANA plates, and screened them with monoclonal antibody 1B2-1B7 (MAb 1B2). MAb 1B2 is specific for Gal-GlcNAc and reacts only with asialylated GC. We isolated 13 MAb 1B2-reactive mutants, including five null mutants, that had Stase activities ranging from barely detectable to fivefold less than that of wild-type (WT) F62. The LOS phenotype of Stase null mutants was identical to that of WT F62, yet the mutants could not sialylate their LOS when grown with CMP-NANA. The Stase null phenotype was rescuable to Stase+ by transformation with chromosomal DNA from WT F62. Stase null mutants remained serum sensitive even when grown with CMP-NANA. One Stase null mutant, ST94A, adhered to and invaded the human cervical epithelial cell line ME-180 at levels indistinguishable from that of WT F62 in the absence of CMP-NANA. In human neutrophil studies, ST94A stimulated the oxidative burst in and adhered to human neutrophils at levels similar to those of WT F62. ST94A and WT F62 were also phagocytically killed by neutrophils at similar levels. These results indicate that expression of Stase activity is not required for interaction of GC with human cells.
淋病奈瑟菌（淋球菌[GC]）中的唾液酸转移酶（Stase）将胞苷5'-单磷酸-N-乙酰神经氨酸（CMP-NANA）中的唾液酸（N-乙酰神经氨酸[NANA]）主要转移至Galβ-1,4N-乙酰葡糖胺（Gal-GlcNAc）-R脂寡糖（LOS）结构中的末端半乳糖（Gal）残基上。唾液酸化的淋球菌可抵抗正常人血清的杀伤作用，有时对上皮细胞的侵袭能力降低，且对人中性粒细胞的黏附及刺激作用减弱。我们质疑在没有外源性CMP-NANA的情况下，Stase本身是否会调节淋球菌与人类上皮细胞及中性粒细胞的相互作用。为此，我们用甲磺酸乙酯处理F62菌株，并在CMP-NANA平板上培养了约175,000个菌落，并用单克隆抗体1B2-1B7（MAb 1B2）对其进行筛选。MAb 1B2对Gal-GlcNAc具有特异性，且仅与去唾液酸化的淋球菌发生反应。我们分离出13个MAb 1B2反应性突变体，包括5个无活性突变体，其Stase活性范围从几乎检测不到到比野生型（WT）F62低五倍。Stase无活性突变体的LOS表型与WT F62相同，但当与CMP-NANA一起培养时，这些突变体无法使其LOS唾液酸化。通过用WT F62的染色体DNA进行转化，Stase无活性表型可恢复为Stase+。即使与CMP-NANA一起培养，Stase无活性突变体仍对血清敏感。在没有CMP-NANA的情况下，一个Stase无活性突变体ST94A对人宫颈上皮细胞系ME-180的黏附及侵袭水平与WT F62无明显差异。在人中性粒细胞研究中，ST94A对人中性粒细胞的氧化爆发的刺激及黏附水平与WT F62相似。ST94A和WT F62也被中性粒细胞以相似水平吞噬杀灭。这些结果表明，淋球菌与人类细胞相互作用并不需要Stase活性的表达。
