Single-cell glycomics analysis by CyTOF-Lec reveals glycan features defining cells differentially susceptible to HIV

High-parameter single-cell phenotyping has enabled in-depth classification and interrogation of immune cells, but to date has not allowed for glycan characterization. Here, we develop CyTOF-Lec as an approach to simultaneously characterize many protein and glycan features of human immune cells at the single-cell level. We implemented CyTOF-Lec to compare glycan features between different immune subsets from blood and multiple tissue compartments, and to characterize HIV-infected cell cultures. Using bioinformatics approaches to distinguish preferential infection of cellular subsets from viral-induced remodeling, we demonstrate that HIV upregulates the levels of cell surface fucose and sialic acid in a cell-intrinsic manner, and that memory CD4+ T cells co-expressing high levels of fucose and sialic acid are highly susceptible to HIV infection. Sialic acid levels were found to distinguish memory CD4+ T cell subsets expressing different amounts of viral entry receptors, pro-survival factors, homing receptors, and activation markers. The ability of sialic acid to distinguish memory CD4+ T cells with different susceptibilities to HIV infection was experimentally validated through sorting experiments. Together, these results suggest that HIV remodels not only cellular proteins but also glycans, and that glycan expression can differentiate memory CD4+ T cells with vastly different susceptibility to HV infection.

高参数单细胞表型分析（high-parameter single-cell phenotyping）已实现免疫细胞的深度分类与功能解析，但截至目前仍无法完成聚糖表征。在此，我们开发了CyTOF-Lec技术，可在单细胞层面同时表征人类免疫细胞的多种蛋白质与聚糖特征。我们运用该技术，对比了血液及多种组织区域中不同免疫亚群的聚糖特征，并对人类免疫缺陷病毒（HIV）感染的细胞培养物进行了表征。通过生物信息学方法区分细胞亚群的优先感染与病毒诱导的细胞重塑，我们证实HIV会以细胞内在方式上调细胞表面岩藻糖与唾液酸的表达水平，且共表达高水平岩藻糖和唾液酸的记忆CD4+ T细胞对HIV感染具有极高易感性。研究发现，唾液酸水平能够区分表达不同水平病毒进入受体、促存活因子、归巢受体及激活标志物的记忆CD4+ T细胞亚群。通过细胞分选实验，我们在实验层面验证了唾液酸可区分对HIV感染易感性不同的记忆CD4+ T细胞这一能力。综上，上述结果表明HIV不仅会重塑细胞蛋白质，还会改变聚糖表达；而聚糖表达可区分对HIV感染易感性差异显著的记忆CD4+ T细胞。