Dendritic Cells Compare the Similarity of Endogenous and Exogenous Antigens

Here we demonstrate by the use of extensive controls and stringent statistical analysis that dendritic cells differentially regulate hundreds of different genes based upon sequence similarity of endogenously- and exogenously-loaded antigens and in a T-cell independent fashion. When endogenously and exogenously-derived antigens are identical, dendritic cells upregulate many different components of the Th-1 response, favoring the priming of CD8+ effectors and promulgating cellular immunity. Keywords: Loading methodology comparison Dendritic cells were loaded by 1 of 5 different methods, then matured for 48 hours. Total cellular RNA was then extracted from 9 unloaded DC populations, 10 mRNA-loaded populations, 11 lysate-loaded populations, 7 doubly-loaded (matched) populations, and 7 doubly-loaded (mismatched) populations, a total of 44 different experiments. Each population was derived from a different normal human donor. Matched/mismatched refers to the source of the mRNA and lysate used to load the DCs. Matched signifies that the mRNA and lysate came from the same source. Mismatched signifies that the mRNA and lysate came from disparate sources. Gene expression profiles were then determined according to the method by which the DCs had been loaded. Genes were identified as differentially expressed by DCs doubly-loaded with matched antigens, only if they were significantly different from all of the other four controls. Significance was defined as Cohen’s |d| > 1.0 (large effect) and q-value (Benjamini-Hochberg false discovery) < 0.01.

本研究通过设置广泛对照与严格统计分析，证实树突状细胞（dendritic cells）可依据内源性与外源性加载抗原的序列相似性，以T细胞非依赖方式对数百种不同基因进行差异性调控。当内源性与外源性来源抗原完全一致时，树突状细胞会上调Th1型免疫应答的多种相关组分，偏好CD8+效应细胞的致敏过程，并强化细胞免疫应答。
关键词：加载方法比较
本研究采用5种不同方法之一对树突状细胞进行抗原加载，随后将其培养成熟48小时。随后从9组未加载抗原的树突状细胞（DC）样本、10组mRNA加载样本、11组裂解物加载样本、7组匹配型双重加载样本以及7组非匹配型双重加载样本中提取总细胞RNA，共计完成44组独立实验。每组样本均来自不同的健康人类供体。
匹配/非匹配指的是用于加载树突状细胞的mRNA与裂解物的来源属性：匹配组表示mRNA与裂解物取自同一供体来源，而非匹配组则表示二者取自不同的供体来源。
随后根据树突状细胞的抗原加载方法对基因表达谱进行检测。仅当匹配型双重加载树突状细胞的基因表达与其余四组对照均存在显著差异时，该基因才被认定为差异性表达基因。显著性判定标准为：科恩|d|>1.0（即大效应量）且q值（本杰米尼-霍赫伯格错误发现率）<0.01。