Molecular Characterizaiton of LFA-1-like Molecule on Exocrine Glands in Patients with Malignant Tumor.

我们以前报道过，使用LFA-1 α特异性单克隆抗体（mAb）2F 12和HVS 6 B6，化学定义的LFA-1抗原（LFA-1样抗原）在恶性疾病患者的各种外分泌组织中表达。我们在本手稿中研究了白细胞上的LFA-1和MKN-45.16上的LFA-1样抗原之间在分子水平上的差异，MKN-45.16是来自表达大量LFA-1样抗原的腺癌细胞系MKN 45的亚系。LFA-1样抗原与mAb 2F 12或HVS 6 B6反应，但与其他5种不同的LFA-1 α（CD 11 a）特异性或4种LFA-1 β（CD 18）特异性mAb中的任何一种均不反应。在非还原和还原条件下，MAb 2F 12从MKN 45.16细胞免疫沉淀200 KD分子量的膜蛋白（LFA-1样抗原），而从单核细胞系（THP-1）免疫沉淀180 KD（LFA-1 α）和95 KD（LFA-1 β）蛋白。通过N-聚糖处理免疫沉淀物进一步证实了分子差异。双向凝胶电泳结果表明，LFA-1样抗原的等电点为6.0，而莱亚-1 α和LFA-1 β的等电点分别为6.0和4.7。LFA-1 α基因在MKN 45. 16细胞中的表达在mRNA水平上通过6组不同的LFA-1 α特异性寡核苷酸和逆转录聚合酶链反应检测不到。这些结果表明腺癌细胞系上的LFA-1样抗原与白细胞上的LFA-1是不同的分子。

We previously reported that the immunohistochemically defined LFA-1 antigen (LFA-1-like antigen) was expressed on various exocrine tissues uninvolved by tumors in patients with malignant diseases using LFA-1alpha-specific monoclonal antibodies (mAb) 2F12 and HVS6B6. We investigated in this manuscript differences at the molecular level between LFA-1 on leukocytes and LFA-1-like antigen on MKN-45.16, a subline derived from an adenocarcinoma line MKN45 that expresses a high amount of LFA-1-like antigen. LFA-1-like antigen was reactive to mAb 2F12 or HVS6B6, but not to any of the other five different LFA-1alpha (CD11a) -specific or four LFA-1beta (CD18) -specific mAb. MAb 2F12 immunoprecipitated a 200 KD molecular weight membrane protein (LFA-1-like antigen) from MKN45.16 cells, whereas it precipitated 180 KD (LFA-1alpha) and 95 KD (LFA-1beta) proteins form a monocytic cell line (THP-1) under both non-reducing and reducing conditions. The molecular difference was ocnfirmed further by N-glycanse treatment of the immunoprecipitates. The isoelectric point of LFA-1-like antigen was 6.0, whereas that of LEA-1alpha and LFA-1beta was 6.0 and 4.7, respectively, by two-dimensional gel electrophoresis. Expression of LFA-1alpha gene on MKN45.16 cells was not detected at the mRNA level by six different sets of LFA-1alpha specific oligonucleotides and reverse transcription-polymerase chain reaction. These results indicated that LFA-1-like antigen on an adenocarcinoma cell line was a distinct molecule from LFA-1 on leukocyte.