Department of Research and Development, The Korean Institute of Tuberculosis, 168-5 Osongsaengmyeong4-ro, Heungdeok-gu, Cheongju-si, Chungcheongbuk-do 28158, Korea.
Division of Antimicrobial Resistance, Center for Infectious Disease Research, Korea National Institute of Health, Korea Centers for Disease Control and Prevention, 187 Osongsaengmyeong2-ro, Heungdeok-gu, Cheongju-si, Chungcheongbuk-do 28159, Korea.
Curr Pharm Biotechnol. 2019;20(7):562-572. doi: 10.2174/1389201020666190528093432.
Interferon-gamma release assays (IGRAs) are blood tests used to measure the amount of interferon-γ (IFN-γ) released by T lymphocytes after stimulation by antigens specific for the diagnosis of latent tuberculosis infection. A mitogen serves as a positive control to assess the immune function in IGRAs.
This in vitro study was conducted to evaluate IFN-γ production by human whole blood stimulated with heat-treated and/or cation-supplemented phytohemagglutinin (PHA), concanavalin A (Con A) and pokeweed mitogen (PWM), using QuantiFERON-TB Gold Kit ELISA tests.
The optimal concentrations of PWM, Con A and PHA for IGRAs were 2 µg/mL, 5 µg/mL and 10 µg/mL, respectively. The results showed that IFN-γ production in response to PWM was the highest and PHA was the lowest amount. The median values of three mitogens were in the following order: PWM≥Con A≥ positive control>>PHA-P>>negative control. PWM and PHA were heat stable, while Con A was heat sensitive. The mitogen response of lymphocytes to untreated or heat-treated PWM and heat-treated Con A was increased in 1 mM Ca2+-supplemented groups, whereas the response to heat-treated PHA was decreased. Exposure to 1 mM Mg2+ had no effect on untreated or heat-treated PWM, and a concentration of 1 mM Zn2+ inhibited the stimulation of un-treated PWM. We found that calcium supplementation improved the PWM-induced production of IFN-γ.
Therefore, PWM is an appropriate mitogen for use as a positive control in IGRAs. It is a potential indicator of cytokine production in the diagnostic as well as research settings, and calcium supplementation improved stimulation.
干扰素-γ 释放试验（IGRAs）是一种血液检测，用于测量在刺激抗原特异性 T 淋巴细胞后释放的干扰素-γ（IFN-γ）的量，以诊断潜伏性结核感染。有丝分裂原作为阳性对照，用于评估 IGRAs 中的免疫功能。
本体外研究旨在使用 QuantiFERON-TB Gold Kit ELISA 试验评估经热处理和/或阳离子补充的植物血凝素（PHA）、伴刀豆球蛋白 A（Con A）和美洲商陆素（PWM）刺激的人全血中 IFN-γ 的产生。
PWM、Con A 和 PHA 分别用于 IGRAs 的最佳浓度为 2 µg/mL、5 µg/mL 和 10 µg/mL。结果表明，PWM 刺激后 IFN-γ 的产生最高，PHA 产生的 IFN-γ 最少。三种有丝分裂原的中位数值依次为：PWM≥Con A≥阳性对照>>PHA-P>>阴性对照。PWM 和 PHA 热稳定，而 Con A 热敏感。未经处理或热处理的 PWM 和热处理的 Con A 刺激下淋巴细胞对有丝分裂原的反应在 1 mM Ca2+补充组中增加，而热处理的 PHA 反应减少。暴露于 1 mM Mg2+对未经处理或热处理的 PWM 没有影响，而 1 mM Zn2+的浓度抑制未经处理的 PWM 的刺激。我们发现钙补充可改善 PWM 诱导的 IFN-γ 产生。
因此，PWM 是 IGRAs 中用作阳性对照的合适有丝分裂原。它是诊断和研究环境中细胞因子产生的潜在指标，钙补充可改善刺激作用。
