Analysis of adhesion molecules on mast cells

整合素家族的粘附分子不仅与白细胞迁移有关，而且与白细胞活化有关。本研究描述了纤维连接蛋白受体整合素在大鼠肥大细胞上的表达和功能。大鼠嗜碱性白血病细胞系（RBL-2H3）和酚酯刺激的大鼠腹膜肥大细胞粘附在纤维连接蛋白（FN）、玻璃体连接蛋白和纤维蛋白原上。这些肥大细胞表达纤维连接蛋白受体整合素，包括极迟抗原(VLA)-4， VLA-5和virtonectin受体（VNR），通过免疫荧光染色和新建立的mab与大鼠α 4 (mrα 4-1), α 5 （HMalpha5-1）或β 3 （HMbeta3-1）链的整合素分子反应抑制FN粘附来估计。β -己糖氨酸酶释放是肥大细胞脱颗粒的标志，由高亲和力IgE受体（FcepsilonRI）介导的刺激触发，rbr - 2h3细胞粘附于免疫化的FN、MRalpha4-1、HMalpha5-1或HMbeta3-1后，β -己糖氨酸酶释放增强。可溶性MRalpha4-1、HM alpha5-1和HMbeta3-1以及GRGDSP和DELPQLVTLPHPNHLGPEILDVPST肽分别抑制了vra -5/VNR和vra -4与FN的结合，从而抑制了β -己糖氨酸酶释放FN的增强。在体内，同时s.c.注射MRalpha4-1、HMalpha5-1和HMbeta3-1可抑制IgE抗dnp和DNP-BSA诱导的被动皮肤过敏反应。这些结果表明，FN受体整合素在体外和体内均对调节肥大细胞的活化起重要作用。

Adhesion molecules of the integrin family are implicated not only in leukocyte migration but also in leukocyte activation. Here we characterize the expression and function of fibronectin receptor integrins on rat mast cells. A rat basophilic leukemia cell line (RBL-2H3) and phorbol ester-stimulated rat peritoneal mast cells adhered to fibronectin (FN), vitronectin and fibrinogen. These mast cells expressed fibronectin receptor integrins, including very late antigen (VLA)-4, VLA-5 and virtonectin receptor (VNR), as estimated by immunofluorescent staining and inhibition of FN adherence by newly established mAbs reactive with the rat alpha4 (MRalpha4-1), alpha5 (HMalpha5-1) or beta3 (HMbeta3-1) chains of the integrin molecules. The beta-hexosaminidase release, a marker for mast cell degranulation, triggered by high affinity IgE receptor (FcepsilonRI) -mediated stimulation, was enhanced by adhesion of RBL-2H3 cells to either immunobilized FN,MRalpha4-1, HMalpha5-1, or HMbeta3-1. This FN enhancement of beta-hexosaminidase release was inhibited by soluble MRalpha4-1, H M alpha5-1, and HMbeta3-1 as well as by GRGDSP and DELPQLVTLPHPNHLGPEILDVPST peptides which abrogate VLA-5/VNR and VLA-4 binding to FN respectively. In vivo, passive cutaneous anaphylaxis induced by IgE anti-DNP and DNP-BSA was inhibited by concurrent s.c. injection of MRalpha4-1, HMalpha5-1, and HMbeta3-1. These results demonstrate that FN receptor integrins expressed on rat mast cells play an important role in regulating mast cell activation both in vitro and in in vivo.