重组人HMGN2多克隆抗体的制备及应用

Production of HMGN2 Polyclonal Antibody by Immunization with Recombinant GST-HMGN2 Fusion Protein and Its Application to Analysis of HMGN2 Distribution in Human Monocytes

目的制备人高迁移率非组蛋白N2(HMGN2)多克隆抗体,并用于HMGN2的亚细胞定位分析。方法提取人淋巴因子激活的杀伤细胞(LAK)总RNA,应用RT-PCR从其总RNA中分离HMGN2cDNA,以pGEX-1λT为载体,构建HMGN2基因大肠杆菌表达载体。应用GST亲合层析柱分离GST-HMGN2融合蛋白,将此融合蛋白免疫新西兰兔,获得抗血清经正辛酸-硫酸铵分步沉淀法初步纯化。用ELISA法检测HMGN2抗体,免疫细胞化学染色法分析HMGN2的亚细胞分布。结果经酶切产物电泳分析和DNA序列测定证明成功构建出HMGN2基因重组原核表达载体pGEX-1λT-HMGN2。转化大肠杆菌经异丙基-b-D-硫代半乳糖苷(IPTG)诱导后获得相对分子质量约35×103的GST-HMGN2融合蛋白。该融合蛋白免疫所得免疫血清经ELISA检测显示获得滴度为1∶2000的较高效价的兔抗人HMGN2多克隆抗体。并应用此抗体对THP-1细胞进行的免疫细胞化学染色显示,经LPS刺激后除细胞核外,胞浆亦明显着色。而且用ELISA法在细胞培养液亦检测到HMGN2。结论本实验成功制备出HMGN2特异多克隆抗体,免疫细胞化学分析初步证明在LPS刺激下HMGN2不仅分布于单核吞噬细胞核,还分布于细胞浆,并可释放到细胞外。

Objective To prepare high mobility group chromosomal protein N2(HMGN2) polyclonal antibodies and determine the subcellular localization of HMGN2 in human monocytes. Methods The recombinant prokaryotic expression vector pGEX-1λT-HMGN2 was constructed and E.coli-based product of GST-HMGN2 fusion protein was prepared and used to immunize rabbit for producing the anti-serum against HMGN2. The polyclonal antibodies were partially purified by caprylic acid and ammonium sulfate precipitation. The titter of specific polyclonal antibodies against HMGN2 was detected by ELISA. The immunocytochemical staining was performed to determine the distribution of HMGN2 in THP-1 cells. Results Gel electrophoresis of the enzyme-digested recombinant plasmid and the DNA sequencing confirmed that the recombinant prokaryotic expression vector pGEX-1λT-HMGN2 was correctly constructed. After IPTG induction, the recombinant-transformed E.coli produced a bulk of GST-HMGN2 fusion protein. The polyclonal antibodies to HMGN2 was obtained from the serum of rabbit immunized with GST-HMGN2 fusion protein and its ELISA titer was (1∶2000.) The immunocytochemistry staining indicated that when stimulated with LPS, HMGN2 was present not only in THP-1 nucleus but also in the cytoplasm. The presence of HMGN2 was also detected in the culture supernatant. Conclusion This result suggests that recombinant peptide fusion protein could be used to produce peptide antibody. HMGN2 could be present in the cytoplasm of monocytes and release to the extracellular environment when stimulated with lipopolysaccharide(LPS).