Perregaux D G, McNiff P, Laliberte R, Conklyn M, Gabel C A
Department of Respiratory, Allergy, Immunology, Inflammation, and Infectious Diseases, Pfizer Central Research, Groton, CT 06340, USA.
J Immunol. 2000 Oct 15;165(8):4615-23. doi: 10.4049/jimmunol.165.8.4615.
Cultured monocytes and macrophages stimulated with LPS produce large quantities of proIL-1beta, but release little mature cytokine to the medium. The efficiency at which the procytokine is converted to its active 17-kDa species and released extracellularly is enhanced by treating cytokine-producing cells with a secretion stimulus such as ATP or nigericin. To determine whether this need for a secretion stimulus extends to blood, individual donors were bled twice daily for 4 consecutive days, and the collected blood samples were subjected to a two-step IL-1 production assay. LPS-activated blood samples generated cell-free IL-1beta, but levels of the extracellular cytokine were greatly increased by subsequent treatment with ATP or nigericin. Specificity and concentration requirements of the nucleotide triphosphate effect suggests a P2X(7) receptor involvement. Quantities of IL-1beta generated by an individual donor's blood in response to the LPS-only and LPS/ATP stimuli were relatively consistent over the 4-day period. Between donors, consistent differences in cytokine production capacity were observed. Blood samples treated with ATP also demonstrated enhanced IL-18 production, but TNF-alpha levels decreased. Among leukocytes, monocytes appeared to be the most affected cellular targets of the ATP stimulus. These studies indicate that an exogenous stimulus is required by blood for the efficient production of IL-1beta and IL-18, and suggest that circulating blood monocytes constitutively express a P2X(7)-like receptor.
用脂多糖（LPS）刺激培养的单核细胞和巨噬细胞会产生大量的前白细胞介素-1β（proIL-1β），但释放到培养基中的成熟细胞因子很少。通过用诸如三磷酸腺苷（ATP）或尼日利亚菌素等分泌刺激物处理产生细胞因子的细胞，可以提高前细胞因子转化为其活性17 kDa形式并释放到细胞外的效率。为了确定这种对分泌刺激的需求是否扩展到血液中，对个体供体连续4天每天采血两次，并对采集的血样进行两步白细胞介素-1产生测定。LPS激活的血样产生了无细胞的白细胞介素-1β，但随后用ATP或尼日利亚菌素处理后，细胞外细胞因子的水平大大增加。三磷酸核苷酸效应的特异性和浓度要求表明涉及P2X(7)受体。在4天的时间里，个体供体的血液对仅LPS和LPS/ATP刺激产生的白细胞介素-1β的量相对一致。在供体之间，观察到细胞因子产生能力存在一致差异。用ATP处理的血样也显示白细胞介素-18的产生增加，但肿瘤坏死因子-α水平降低。在白细胞中，单核细胞似乎是ATP刺激最受影响的细胞靶点。这些研究表明，血液需要外源性刺激才能有效产生白细胞介素-1β和白细胞介素-18，并表明循环血单核细胞组成性表达一种类似P2X(7)的受体。
