A Novel Sialylation Site on Neisseria gonorrhoeae Lipooligosaccharide Links Heptose II Lactose Expression with Pathogenicity.
A Novel Sialylation Site on Neisseria gonorrhoeae Lipooligosaccharide Links Heptose II Lactose Expression with Pathogenicity.
复制标题
淋病奈瑟菌脂寡糖上的新型唾液酸化位点将庚糖 II 乳糖表达与致病性联系起来。
DOI：
10.1128/iai.00285-18
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发表时间：
2018
影响因子：
3.1
通讯作者：
Rice,PeterA
中科院分区：
文献类型：
--
作者：
Ram,Sanjay;Gulati,Sunita;Lewis,LisaA;Chakraborti,Srinjoy;Zheng,Bo;DeOliveira,RosaneB;Reed,GeorgeW;Cox,AndrewD;Li,Jianjun;StMichael,Frank;Stupak,Jacek;Su,Xiao-Hong;Saha,Sudeshna;Landig,CorinnaS;Varki,Ajit;Rice,PeterA
淋球菌脂寡糖(LOS)由庚糖I(HEPI)延伸而来的乳酸-N-新四糖(LNnT)参与了淋病的发病过程。此前，淋球菌LOS唾液酸转酯酶(LST)在菌株15253的Triton X-100提取物中分析LOS，该菌株表达来自HEPI和HEII的乳糖，这是与单抗(MAb)2C7结合所需的最小结构。正在进行的工作表明，在含有胞苷单磷酸-N-乙酰神经氨酸(CMP-Neu5Ac)的培养基中生长15253能够与CD33/Siglec-3结合，CD33Siglec-3是一种结合唾液酸的细胞表面受体，这表明完整淋球菌丢失时乳糖的末端可以被唾液酸化。用质谱仪检测到缺失的菌株15253和只含有来自HEPI和HEII的乳糖的MS11突变体；删除HEII乳糖使Neu5Ac不能被检测到。HEII乳糖Neu5Ac对α2-3特异性神经氨酸酶的抗性提示与α2-6连锁。尽管与因子H结合的增加无关，HepII乳糖唾液酸化可抑制淋球菌上的补体C3沉积。缺失Lst或HepII乳糖的15253株突变株在小鼠体内显著减弱，证实了HepII Neu5Ac在毒力中的重要性。来自南京的75株临床微传代分离株中国均表达HEII乳糖，与单抗2C7的反应证明，单抗2C7对75株连续采集的前62株分离株具有杀菌作用。单抗2C7能有效抑制小鼠阴道定植15253。总之，这个新的唾液酸化位点可以解释淋球菌丙型肝炎病毒在体内的普遍存在。我们的发现加强了2C7表位作为疫苗抗原和单抗2C7作为免疫治疗性抗体的候选资格。
Sialylation of lacto-N-neotetraose (LNnT) extending from heptose I (HepI) of gonococcal lipooligosaccharide (LOS) contributes to pathogenesis. Previously, gonococcal LOS sialyltransterase (Lst) was shown to sialylate LOS in Triton X-100 extracts of strain 15253, which expresses lactose from both HepI and HepII, the minimal structure required for monoclonal antibody (MAb) 2C7 binding. Ongoing work has shown that growth of 15253 in cytidine monophospho-N-acetylneuraminic acid (CMP-Neu5Ac)-containing medium enables binding to CD33/Siglec-3, a cell surface receptor that binds sialic acid, suggesting that lactose termini on LOSs of intact gonococci can be sialylated. Neu5Ac was detected on LOSs of strains 15253 and an MS11 mutant with lactose only from HepI and HepII by mass spectrometry; deleting HepII lactose rendered Neu5Ac undetectable. Resistance of HepII lactose Neu5Ac to desialylation by α2-3-specific neuraminidase suggested an α2-6 linkage. Although not associated with increased factor H binding, HepII lactose sialylation inhibited complement C3 deposition on gonococci. Strain 15253 mutants that lacked Lst or HepII lactose were significantly attenuated in mice, confirming the importance of HepII Neu5Ac in virulence. All 75 minimally passaged clinical isolates from Nanjing, China, expressed HepII lactose, evidenced by reactivity with MAb 2C7; MAb 2C7 was bactericidal against the first 62 (of 75) isolates that had been collected sequentially and were sialylated before testing. MAb 2C7 effectively attenuated 15253 vaginal colonization in mice. In conclusion, this novel sialylation site could explain the ubiquity of gonococcal HepII lactosein vivo. Our findings reinforce the candidacy of the 2C7 epitope as a vaccine antigen and MAb 2C7 as an immunotherapeutic antibody.