Li Y, Simons F E, Jay F T, HayGlass K T
Department of Immunology, University of Manitoba, Winnipeg, Canada.
Int Immunol. 1996 Jun;8(6):897-904. doi: 10.1093/intimm/8.6.897.
Difficulties in detecting human IL-4 synthesis in antigen-driven primary culture have led to widespread reliance on less physiologic approaches to T cell activation. Although there is general agreement of a Th2-like bias, the precise defects in cytokine responsiveness remain controversial. Analysis of cytokine protein production by fresh, unselected cell populations in response to cognate, antigen-driven stimulation remains an important goal. Here, limiting dilution analysis (LDA) was used to evaluate antigen-stimulated cytokine gene expression by fresh peripheral blood mononuclear cells (PBMC). PBMC from 19 grass pollen sensitive, allergic rhinitis subjects and normal, non-atopic controls were evaluated 1 month after natural reimmunization (the peak of the local grass pollen season). Surprisingly, highly atopic subjects and clinically non-allergic individuals exhibited virtually equivalent antigen-specific, CD4-dependent cytokine production in response to short-term culture with these common environmental antigens. As anticipated, pronounced increases in Th2-like activity were evident in the circulating immune repertoire of grass pollen sensitive individuals, leading to a median ratio of antigen-stimulated IFN-gamma:IL-4 frequencies of 117:1 among normal subjects versus 4:1 among those with allergic rhinitis (Mann-Whitney U-test, P = 0. 00067). This Th2-like bias reflected both a lower frequency of IFN-gamma-producing cells and a markedly increased frequency of IL-4-producing cells in the circulating grass-pollen specific repertoire of atopic donors. The observation that every atopic and normal subject produced IFN-gamma (+/-IL-4) following antigen re-stimulation argues that the decision as to whether allergy or (clinical) tolerance results, hinges not on a genetically determined capacity of whether allergen-reactive T cells can be stimulated in any given individual by chronic exposure to ubiquitous environmental antigens, but on the nature of the cytokine response that comes to dominate that individual's response.
在抗原驱动的原代培养中检测人白细胞介素-4合成存在困难，这导致人们广泛依赖生理特性较差的T细胞激活方法。尽管普遍认为存在Th2样偏向，但细胞因子反应性的确切缺陷仍存在争议。分析新鲜、未分选的细胞群体在同源抗原驱动刺激下的细胞因子蛋白产生情况仍是一个重要目标。在此，采用有限稀释分析（LDA）来评估新鲜外周血单核细胞（PBMC）对抗原刺激的细胞因子基因表达。在自然再次免疫（当地草花粉季节高峰期）1个月后，对19名草花粉敏感的变应性鼻炎受试者和正常非特应性对照的PBMC进行了评估。令人惊讶的是，高度特应性受试者和临床无过敏个体在与这些常见环境抗原短期培养后，表现出几乎相同的抗原特异性、CD4依赖性细胞因子产生。正如预期的那样，草花粉敏感个体的循环免疫库中Th2样活性明显增加，导致正常受试者中抗原刺激的干扰素-γ：白细胞介素-4频率的中位数比值为117：1，而变应性鼻炎患者中为4：1（曼-惠特尼U检验，P = 0.00067）。这种Th2样偏向反映了特应性供体循环中草花粉特异性免疫库中产生干扰素-γ的细胞频率较低，而产生白细胞介素-4 的细胞频率显著增加。每个特应性和正常受试者在抗原再刺激后都产生干扰素-γ（±白细胞介素-4）这一观察结果表明，过敏或（临床）耐受结果的决定，并不取决于遗传决定的能力，即变应原反应性T细胞在任何给定个体中是否能被长期暴露于普遍存在的环境抗原所刺激，而是取决于主导该个体反应的细胞因子反应的性质。
