SARS-CoV感染人群抗体的跟踪研究及意义

目的对2003年12月、2006年6月和2008年6月3次采集的严重急性呼吸综合征(severe acute respiratory syndrome,SARS)患者血清进行冠状病毒抗体(SARS-CoVIgG/IgM)的动态检测,并分析其意义。方法选择2003年确诊的21例SARS患者为研究对象,同期工作的29例未感染人群为对照组,采用酶联免疫法(ELISA)检测抗SARS-CoVIgG和IgM抗体,采用GEN-S全自动血球分析仪器对患者血细胞进行分析,采用AU5400生化分析仪测定血清免疫球蛋白含量变化。结果SARS患者在感染后第3年血清抗SARS-CoVIgM抗体阳性率为23.8%(5/21),第5年抗SARS-CoVIgM全部消失;而抗SARS-CoVIgG抗体在感染后第3年其滴度有下降趋势,但全部为阳性,感染后第5年血清抗SARS-CoVIgG阳性率高达90%(19/21)。对照组血清抗SARS-CoVIgM/IgG全部阴性。所有感染者在感染后第3年和第5年血液细胞分类和血清免疫球蛋白含量均与正常人群比较无显著差异。结论SARS患者在感染冠状病毒后第5年表现为抗SARS-CoVIgG持续阳性,其血细胞分类和血清免疫球蛋白等指标持续正常,支持SARS-CoVIgG可做为保护性抗体的说法。

Reductive amination of ketones with ammonium catalyzed by a newly identified Brevibacterium epidermidis strain for the synthesis of(S)-chiral amines

The asymmetric reductive amination of achiral ketones with ammonia is a particularly attractive reaction for the synthesis of chiral amines.Although several engineered amine dehydrogenases have been developed by protein engineering for the asymmetric reductive amination of ketones,they all display(R)‐stereoselectivity.To date,there is no report of an(S)‐stereoselective biocatalyst for this reaction.Herein,a microorganism named Brevibacterium epidermidis ECU1015 that catalyzes the(S)‐selective reductive amination of ketones with ammonium has been successfully isolated from soil.Using B.epidermidis ECU1015 as the catalyst,the asymmetric reductive amination of a set of phenylacetone derivatives was successfully carried out,yielding the corresponding(S)‐chiral amines with moderate conversion and>99%enantiomeric excess.