Knol E F, Kuijpers T W, Mul F P, Roos D
Central Laboratory of The Netherlands Red Cross Blood Transfusion Service, Amsterdam.
J Immunol. 1993 Nov 1;151(9):4926-33.
For a better insight into the mechanisms determining the recruitment of human basophilic granulocytes from the circulation to sites of allergic reactions, we studied the homotypic aggregation of these cells. The aggregation was studied with > 95% pure basophil suspensions obtained from peripheral blood in a double-color flow cytometric analysis. Homotypic aggregation was induced by treatment of the basophils with anti-IgE, house dust mite allergen, the chemoattractant FMLP, PMA, or IL-3. The aggregation by anti-IgE was, in part, mediated by interactions with Fc gamma R-II as indicated by 43 +/- 15% inhibition after pretreatment with CD32 antibodies. The aggregation was mediated by beta 2-integrins, as was shown by inhibition of the response by CD18 antibodies. The aggregation induced by anti-IgE, allergen, and PMA displayed comparable kinetics (t1/2 max, 3 to 4 min), in contrast to the degranulation of basophils. FMLP induced the most rapid response (t1/2max, 1.6 min). Inhibition of protein kinase C by staurosporine resulted in a strong (> 90%) inhibition of the PMA-induced aggregation, whereas the FMLP-induced aggregation was more than doubled (from 11.7 +/- 1.9 to 24.4 +/- 1.9%). Staurosporine did not affect the extent of the anti-IgE-induced aggregation, but it induced a retardation of congruent to 10 min. In most experiments, no clear correlation was found between degranulation and aggregation of human basophils. Most strikingly, IL-3 did not induce degranulation but did induce aggregation. Thus, the homotypic aggregation response of human basophils is induced by intracellular signals not necessarily leading to degranulation. This might be important in the physiologic appearance of basophils at sites of allergic late-phase responses or inflammation.
为了更深入了解决定人类嗜碱性粒细胞从循环系统募集到过敏反应部位的机制，我们研究了这些细胞的同型聚集。在双色流式细胞术分析中，使用从外周血获得的纯度>95%的嗜碱性粒细胞悬液研究聚集情况。用抗IgE、屋尘螨变应原、趋化因子FMLP、佛波酯（PMA）或白细胞介素-3（IL-3）处理嗜碱性粒细胞可诱导同型聚集。抗IgE诱导的聚集部分是由与FcγR-II的相互作用介导的，用CD32抗体预处理后抑制率为43±15%。聚集是由β2整合素介导的，CD18抗体抑制反应证明了这一点。抗IgE、变应原和PMA诱导的聚集表现出相似的动力学（t1/2 max，3至4分钟），这与嗜碱性粒细胞的脱颗粒情况不同。FMLP诱导的反应最快（t1/2max，1.6分钟）。星形孢菌素抑制蛋白激酶C导致PMA诱导的聚集受到强烈抑制（>90%），而FMLP诱导的聚集增加了一倍多（从11.7±1.9%增至24.4±1.9%）。星形孢菌素不影响抗IgE诱导的聚集程度，但会使其延迟约10分钟。在大多数实验中，未发现人类嗜碱性粒细胞的脱颗粒与聚集之间有明显相关性。最引人注目的是，IL-3不诱导脱颗粒，但能诱导聚集。因此，人类嗜碱性粒细胞的同型聚集反应是由不一定导致脱颗粒的细胞内信号诱导的。这可能在嗜碱性粒细胞在过敏迟发反应或炎症部位出现的生理过程中起重要作用。
