流式細(xì)胞術(shù)分析的核心在于“圈門(mén)"，所謂“門(mén)"和“區(qū)域"，是指基于特定特征對(duì)細(xì)胞群體進(jìn)行劃分，常通過(guò)FSC（前向散射）、SSC（側(cè)向散射）及表面標(biāo)記物（marker）來(lái)進(jìn)行“圈門(mén)"，以分辨和量化不同的細(xì)胞群。圈門(mén)的第一步通常是根據(jù)細(xì)胞的FSC和SSC特性來(lái)區(qū)分不同的細(xì)胞群。FSC反映了細(xì)胞的大小，SSC則與細(xì)胞的粒度相關(guān)。同時(shí)這些信號(hào)也會(huì)受到樣本預(yù)處理、激光波長(zhǎng)、采集角度、折射率以及鞘液的流速等因素的影響。在分析復(fù)雜樣本（如PBMC外周血單核細(xì)胞）時(shí)，F(xiàn)SC和SSC的組合有助于區(qū)分不同類型的細(xì)胞，如淋巴細(xì)胞與細(xì)胞碎片或死細(xì)胞。通過(guò)調(diào)整閾值，便可以有效排除不相關(guān)的細(xì)胞群體，如死細(xì)胞。

PBMC包含多種不同類型的細(xì)胞。通過(guò)光散射特性，可以將單核細(xì)胞和淋巴細(xì)胞從細(xì)胞碎片和死細(xì)胞中區(qū)分開(kāi)細(xì)胞碎片和死細(xì)胞通常表現(xiàn)出較低的FSC信號(hào)，一般位于密度圖的左下角區(qū)域。為有效排除不相關(guān)的細(xì)胞，可以通過(guò)調(diào)整FSC閾值來(lái)去除這些細(xì)胞，或者通過(guò)進(jìn)一步優(yōu)化圈門(mén)策略，縮小分析范圍。這些方法有助于去除由樣本中的自身熒光或抗體非特異性結(jié)合所引起的背景信號(hào)和死細(xì)胞。此外，使用死活細(xì)胞染料（如DAPI、7-AAD等）也是一種行之有效的手段，可以幫助進(jìn)一步排除死細(xì)胞，確保結(jié)果的可靠性。

參考文獻(xiàn)的圈門(mén)，尤其是血液和脊髓免疫細(xì)胞流式圈門(mén)分析解決方案，可以參考如下這篇文獻(xiàn)。

論文信息：

論文題目：NAAA-regulated lipid signaling in monocytes controls the induction of hyperalgesic priming in mice

期刊名稱：Nature Communications

時(shí)間期卷：15, Article number: 1705 (2024)

在線時(shí)間：2024年2月24日

DOI：doi.org/10.1038/s41467-024-46139-5

產(chǎn)品信息：

貨號(hào)：CP-005-005

規(guī)格：5ml+5ml

品牌：Liposoma

產(chǎn)地：荷蘭

名稱：Clodronate Liposomes and Control Liposomes

辦事處：Target Technology（靶點(diǎn)科技）

血液和脊髓免疫細(xì)胞流式圈門(mén)分析解決方案：

Fluorescence Activated Cell Sorting (FACS)

Blood was drawn via cardiac puncture and incubated with ammonium-chloride-potassium (ACK) buffer for erythrocyte lysis. Leukocytes were stained with anti-CD11b, Zombie NIR, anti-Ly6C, and anti-Ly6G antibodies (Table S1) in antibody-staining buffer (0.2% BSA and 0.1% sodium azide in PBS) for 30?min at 4?°C. Viable cell populations of interest were collected by FACS and quantified using FCS Express 7 (De Novo Software, Pasadena, CA). Gating strategies are illustrated in Figure S1. First, to separate debris from cells, we gated on the side scatter area (SSC-A) versus the forward scatter area (FSC-A) and selected the cell population with a high FSC-A/SSC-A ratio. This fraction was subjected to forward scatter height (FSC-H) versus FSC-A analysis to isolate single cells that displayed a ratio of ～1. The single-cell population was further processed to remove dead cells. Zombie NIR signal-negative cells were collected for the next steps. All FACS processes included these initial gating steps to ensure that only viable single cells were analyzed. From this population, we gated cells based on the expression of cellular marker proteins to isolate cell types of interest. To focus on innate immune cells, we selected cells that were positive for CD11b by plotting the viable cell population as CD11b versus FSC-A and selecting the population that was CD11b+. This was plotted as Ly6C versus Ly6G with the Ly6Chigh cells being divided into groups depending on Ly6G expression. Monocytes were categorized as ‘classical’ (CD11b+ Ly6Chigh Ly6Glow) or ‘non-classical’ (CD11b+ Ly6Clow Ly6Glow), while neutrophils were defined as CD11b+ Ly6Chigh Ly6Ghigh . Expression of the Naaa and Ppara genes in monocytes and neutrophils was quantified by reverse transcription-quantitative polymerase chain reaction (RT-qPCR), as described below, to confirm successful recombination.

The spinal cord underwent enzymatic digestion and mechanical dissociation using a brain dissociation kit (Miltenyi Biotec, Bergisch Gladbach, Germany), following the manufacturer’s instructions. Subsequently, the dissociated spinal cord cells were stained with anti-CD11b and anti-CD45 antibodies (Table S1) in antibody-staining buffer (0.2% BSA and 0.1% sodium azide in PBS) for 30?min at 4?°C. Viable cell populations were collected by FACS and quantified using FCS Express version 7.18.0025 (De Novo Software, Pasadena, CA). Gating strategies are described above. Microglia was plotted as CD45 versus CD11b, which are both established markers for this cell lineage.