Studies on human complement 4 binding protein

1. 人c4结合蛋白（C4BP）的纯化及抗C4BP抗体的制备从1.5L血浆中经BaC12沉淀、脂内吸收、超离心、乙醇/埃塞尔萃取、柱层析（DE52、S400和S300）等多个步骤纯化人C4BPalpha。在兔和小鼠体内培养了针对这种蛋白的抗体。制备单克隆抗体（IgG）。2. 对人类基因组C4BP基因进行分析。该基因由12个外显子组成，长度约为40kb。每个SCR都由单个外显子编码，除了第二个SCR （SCR II）由两个单独的外显子编码。在推测的转录起始位点上游对5'侧翼区域进行了380个碱基的测序。确定了几个可能的转录因子结合位点。3. C4BP α基因在正常肝细胞和肝癌细胞中的表达。C4BPalpha的组成基因表达在肝癌细胞系HepG2中被单核细胞条件培养基、12- o - tetradecanoylpholol -13-acetate、白细胞介素-6和肿瘤坏死因子显著增强，而钙离子载体或白细胞介素-1 - β没有增强。4. 血清C4BP水平测定各种自身免疫性疾病患者血清C4BP水平。在活动性或lac阳性的SLE、Behcet病、大动脉炎、PSS、RA和MCTD患者中，C4BP水平显著升高。C4BP水平与CRP、C3、CH50呈正相关。

1. Purification of human C4-binding protein (C4BP) and development of antibody against the purified C4BP Human C4BPalpha was purified from 1.5L of plasma by multiple steps including BaC12 precipitation, Intralipid absorption, ultracentrifugation, ethanol/ethel extraction, column chromatographies (DE52,S400 and S300). Antibodies against this protein were raised in rabbits and mice. Monoclonal antibody (IgG) was also developed. 2. Human genomic C4BP gene Human genomic C4BPalpha gene was analyzed. This gene consists of 12 exons and spans about 40 kb. Each of the SCRs is encoded by a single exon, except for the second SCR (SCR II), which is encoded by two separate exons. The 5' flanking region was sequenced up to 380 bases upstream from the putative transcription initiation site. Several possible binding sites for transcription factors were identified. 3. Gene expression of the C4BPalpha The gene expression of the C4BP alpha in normal liver cell and hepatoma lines was demonstrated. The constitutive gene expression of C4BPalpha by a hepatoma line, HepG2, was significantly augmented by treatment with monocyte conditioned medium, 12-O-tetradecanoylphorbol-13-acetate,interleukin-6 and tumor necrosis factor but not by a calcium ionophore or interleukin-1beta. 4. Serum levels of C4BP Serum levels of C4BP were measured in patients with various autoimmune disease. Significantly high level of C4BP was observed in patients with active or LAC-positive SLE,Behcet disease, aortitis, PSS,RA and MCTD. The level of C4BP was correlated with CRP, C3 and CH50.