Tharp M D, Suvunrungsi R T, Sullivan T J
J Immunol. 1983 Apr;130(4):1896-901.
We investigated the ability of antigen-IgE interactions to stimulate histamine release from human infant cutaneous mast cells. Skin obtained at circumcision contained numerous perivascular mast cells, as assessed by light and electron microscopy. The histamine content of this tissue averaged 17.7 ng (+/- 1.5 SEM)/mg wet weight. Challenge of 200-microns thick sections of unsensitized skin with varying concentrations of monoclonal murine antibodies to human IgE caused no net release of histamine. After skin sections were incubated in the presence of 5 micrograms/ml of human myeloma IgE (S) for 120 min at 37 degrees C, monoclonal anti-IgE challenge resulted in 40.1% (+/- 6.0 SEM) histamine release. Similar passive sensitization with 1/20 dilutions of serum from humans expressing IgE to purified Juniperus sabinoides (JS) antigen rendered the tissue responsive to specific antigen challenge. Dose-related histamine release occurred over 30 min with optimal release of 12.6% (+/- 2.4 SEM) after stimulation with 100 ng/ml of JS antigen. This reaction required sensitization with serum containing IgE to JS and was antigen-specific. Optimal reactions to antigen occurred at 3 mM added Ca++, 34 degrees C to 37 degrees C, pH 7.2. Antigen-induced release was markedly influenced by the added Ca++ concentration; no release occurred in the absence of Ca++, 54% of the optimal response was observed at 2 mM Ca++, and 28% of the optimal response occurred at 4 mM Ca++. The addition of Mg++ did not influence antigen-induced release. The results of this study provide functional evidence that 1) human infant cutaneous mast cells express Fc-epsilon receptors; 2) these receptors are largely unoccupied in vivo; and 3) stimulation of passively sensitized infant mast cells with anti-IgE or specific antigen leads to immediate histamine release. This new system should permit detailed in vitro studies of immediate hypersensitivity reactions in human skin.
我们研究了抗原 - IgE相互作用刺激人婴儿皮肤肥大细胞释放组胺的能力。通过光学显微镜和电子显微镜评估，包皮环切术中获取的皮肤含有大量血管周围肥大细胞。该组织中组胺含量平均为17.7 ng（±1.5 SEM）/mg湿重。用不同浓度的抗人IgE单克隆鼠抗体刺激未致敏皮肤的200微米厚切片，未引起组胺的净释放。在37℃下，将皮肤切片在5微克/毫升人骨髓瘤IgE（S）存在下孵育120分钟后，单克隆抗IgE刺激导致40.1%（±6.0 SEM）的组胺释放。用表达针对纯化的刺柏（JS）抗原的IgE的人血清1/20稀释液进行类似的被动致敏，使组织对特异性抗原刺激产生反应。在用100 ng/ml的JS抗原刺激后，30分钟内发生剂量相关的组胺释放，最佳释放量为12.6%（±2.4 SEM）。该反应需要用含有针对JS的IgE的血清进行致敏，并且具有抗原特异性。对抗原的最佳反应发生在添加3 mM Ca++、34℃至37℃、pH 7.2的条件下。抗原诱导的释放明显受添加的Ca++浓度影响；在无Ca++时不发生释放，在2 mM Ca++时观察到最佳反应的54%，在4 mM Ca++时发生最佳反应的28%。添加Mg++不影响抗原诱导的释放。本研究结果提供了功能证据，即1）人婴儿皮肤肥大细胞表达Fc - ε受体；2）这些受体在体内大部分未被占据；3）用抗IgE或特异性抗原刺激被动致敏的婴儿肥大细胞会导致立即释放组胺。这个新系统应该允许对人皮肤中的速发型超敏反应进行详细的体外研究。
