SARS冠状病毒单克隆抗体制备及在肺尸检标本染色中的应用

目的制备抗SARS冠状病毒的单克隆抗体,用于SARS的实验室诊断。方法灭活SARS冠状病毒(PUMC01)全病毒免疫BALB／C小鼠,取小鼠脾细胞与骨髓瘤细胞(NS-1)融合,用酶联免疫吸附试验(ELISA)、间接免疫荧光法(IFA)及免疫印迹法对所获得的细胞克隆进行筛选和鉴定,并用其中一株(M2)杂交瘤诱生的腹水单克隆抗体对SARS患者尸检肺组织切片进行免疫组织化学染色。结果共筛选出6株杂交瘤细胞,ELISA及IFA法证实其分泌的单克隆抗体与SARS冠状病毒有特异性反应,与其他常见呼吸道病原体均无交叉反应。免疫双扩散方法鉴定1株杂交瘤细胞(M2)为免疫球蛋白IgG3型,其余5株均为IgG1型。免疫印迹试验显示1株杂交瘤细胞(M2)分泌的抗体与相对分子质量68000的蛋白有特异性反应;4株杂交瘤细胞分泌的抗体与相对分子质量27000的蛋白有特异性反应,1株在免疫印迹上未见到结果。SARS患者尸检肺组织病理切片免疫组织化学染色阳性,在肺泡上皮细胞、支气管上皮细胞及巨噬细胞的胞浆均可见阳性颗粒。结论我们制备的6株单克隆抗体是抗SARS冠状病毒的特异性单克隆抗体,用于SARS尸检肺组织免疫组化染色,结果阳性。

Preparation of monoclonal antibodies against SARS coronavirus and staining usage in lung autopsy specimens

OBJECTIVE: To prepare monoclonal antibodies against SARS coronavirus (SARS-CoV) on the purpose to explore the diagnosis methods of SARS. METHODS: Female BALB/C mice were immunized with disinfected SARS-CoV (PUMC01) and the spleen cells were fused with myeloma NS-1 cells. The hybridoma cell strains were screened by enzyme-linked immunosorbent assay (ELISA), indirect fluorescent-antibody assay (IFA) and Western blotting. Autopsy lung tissue sections from SARS patients were stained with ascites of monoclonal antibody (M2 strain) by immunohistochemical technique. RESULTS: Six strains of hybridomas that produced the monoclonal antibodies against SARS-CoV were obtained. The hybridomas were tested to have specific reactions with SARS-CoV and no cross-reactivates with other common respiratory disease causing pathogens. Of the 6 strains, 1 was identified as the immunoglobulin G3 (IgG3) isotype, 5 were IgG1. Western blotting showed that one strain (M2) reacted with 68000- Dalton (68KD) protein and four strains with 27000-dalton (27KD) protein. Band of M4 stain was not got by western blotting. Brown particles were seen in macrophages and pneumocytes in autopsy lung tissues from SARS patients. CONCLUSION: Monoclonal antibodies we made were specific to the SARS-CoV, and they had been used to detect SARS-CoV in autopsy lung tissues specimens with positive results.