抗SARS病毒N蛋白单克隆抗体的制备和初步应用

目的 制备抗SARS病毒N蛋白的单克隆抗体并研究其初步应用。方法 用基因重组N蛋白免疫小鼠，取免疫后的鼠脾细胞与骨髓瘤细胞融合，筛选分泌抗SAPS病毒N蛋白单克隆抗体细胞株。将阳性细胞株接种小鼠腹腔制备单克隆抗体腹水并对抗体进行纯化，分析纯化抗体的相对亲和力。选择亲和力较高的抗体制备检测SARS病毒抗原的酶联免疫诊断试剂，并对其敏感性和特异性进行分析。结果 共获得11株单克隆抗体细胞株，其中3株单抗与N蛋白具有较高的亲和力，4株纯化单抗与N蛋白反应很弱，其余4株单抗介于两者之间。用亲和力较高的单抗制备检测SARS病毒抗原的诊断试剂，其敏感性可达31PFU／ml，而且与其他呼吸道病毒无交叉反应。结论 该试剂特异性较好，可用于SARS病毒抗原的检测，其敏感性仍需用临床急性期样品进行评价。

Development and preliminary application of monoclonal antibodies against N protein of SARS virus

Objective To develop the monoclonal antibody against N protein of SARS virus and study its applicabilityMethods BALB/c mice were immunized with recombinant N protein Spleen cells were collected and infused with SP2/0 cell The infused cells were screened for anti-N protein antibody with ELISA The positive cells were cloned and injected into abdominal cavity The antibodies were purified from ascites The affinities of those purified antibodies were analyzed with ELISA The ELISA for detection of SARS virus antigen was developed by using antibody with the highest affinity Its sensitivity and specificity were also evaluated primarily Results Eleven monoclonal cells secreting antibody have been developed Three of the 11 purified monoclonal antibodies had very high affinity to N protein, while 4 purified McAbs showed very weak reaction to N protein, the affinities of remaining 4 McAbs were in between The ELISA for detection of SARS virus antigen was developed with McAb 7 Its sensitivity was about 31 PFU/ml and had no cross reaction with other respiratory viruses Conclusion The monoclonal antibody has good specificity and may be used to detect SARS virus antigen However, its sensitivity is to be evaluated further with clinical samples from SARS patients, especially at acute phase