自然杀伤样B(NKB)细胞是表达自然杀伤(NK)和B细胞受体的独特先天性免疫细胞。作为感染的第一反应者,它们分泌IL-18以诱导先天和适应性免疫细胞浸润和激活的关键级联反应。然而,关于NKB细胞在稳态和感染中的作用的研究有限,主要是由于不完整和错误的评估。为了填补这一知识空白,我们研究了信号和运输蛋白的表达,与传统定义的NK和B细胞相比,原始NKB细胞的原位定位和转录组,以及这些细胞在SIV感染中的调节。细胞内信号蛋白和运输标记在初始NKB细胞上差异表达,CD62L和Syk的高表达,和低表达的CD69,α4β7,FcRg,Zap70和CD3z,发现与B细胞比NK细胞更相似。CD20+NKG2a/c+NKB细胞在脾脏中被鉴定,肠系膜淋巴结(MLN),结肠,空肠,通过组织成像和原始恒河猴(RM)的肝脏,NKB细胞计数集中于脾脏和MLN。第一次,单细胞RNA测序(scRNAseq),包括BCR测序,分选的NKB细胞证实NKB细胞是独特的。通过scRNAseq对幼稚脾NKB细胞的转录组学分析显示,NKB细胞经历体细胞超突变并表达Ig受体,类似于B细胞。虽然只有15%的分选的NKB细胞显示KLRC1(NKG2A)和MS4A1(CD20)基因的转录本表达,只有5%的细胞表达KLRC1,MS4A1和IgH/IgL转录本。早在SIV感染后14天和35天,我们观察到RM肠和颊粘膜中NKB频率扩大,分别。Further,粘膜和外周NKB细胞与结直肠细胞因子环境和口腔微生物组变化有关,分别。我们的研究表明,在CD3-CD14-CD20+NKG2A/C+细胞上门控的NKB细胞除了真正的NKB细胞外,还包括转录上常规的B和NK细胞,混淆准确的表型和频率记录,只能使用基因组技术解决。尽管NKB细胞在SIV感染期间明显升高,并且在感染期间与炎症变化有关,进一步的询问是必要的,以准确地确定感染和炎症中NKB细胞的真实表型和意义。
Natural killer-like B (NKB) cells are unique innate immune cells expressing both natural killer (NK) and B cell receptors. As first responders to infection, they secrete IL-18 to induce a critical cascade of innate and adaptive immune cell infiltration and activation. However, limited research exists on the role of NKB cells in homeostasis and infection, largely due to incomplete and erroneous evaluations. To fill this knowledge gap, we investigated the expression of signaling and trafficking proteins, and the in situ localization and transcriptome of naïve NKB cells compared to conventionally-defined NK and B cells, as well as modulations of these cells in SIV infection. Intracellular signaling proteins and trafficking markers were expressed differentially on naïve NKB cells, with high expression of CD62L and Syk, and low expression of CD69, α4β7, FcRg, Zap70, and CD3z, findings which were more similar to B cells than NK cells. CD20+NKG2a/c+ NKB cells were identified in spleen, mesenteric lymph nodes (MLN), colon, jejunum, and liver of naïve rhesus macaques (RM) via tissue imaging, with NKB cell counts concentrated in spleen and MLN. For the first time, single cell RNA sequencing (scRNAseq), including B cell receptor (BCR) sequencing, of sorted NKB cells confirmed that NKB cells are unique. Transcriptomic analysis of naïve splenic NKB cells by scRNAseq showed that NKB cells undergo somatic hypermutation and express Ig receptors, similar to B cells. While only 15% of sorted NKB cells showed transcript expression of both KLRC1 (NKG2A) and MS4A1 (CD20) genes, only 5% of cells expressed KLRC1, MS4A1, and IgH/IgL transcripts. We observed expanded NKB frequencies in RM gut and buccal mucosa as early as 14 and 35 days post-SIV infection, respectively. Further, mucosal and peripheral NKB cells were associated with colorectal cytokine milieu and oral microbiome changes, respectively. Our studies indicate that NKB cells gated on CD3-CD14-CD20+NKG2A/C+ cells were inclusive of transcriptomically conventional B and NK cells in addition to true NKB cells, confounding accurate phenotyping and frequency recordings that could only be resolved using genomic techniques. Although NKB cells were clearly elevated during SIV infection and associated with inflammatory changes during infection, further interrogation is necessary to acurately identify the true phenotype and significance of NKB cells in infection and inflammation.