MULTIPLE DELETIONS OF COMPONENTS OF ANTIGEN PRESENTATION MACHINERY LEADS THE DOWNREGULATION OF HLA CLASS Ⅰ IN A COLON CARCINOMA CELL LINE
The presentation of human leukocyte antigen (HLA) class Ⅰ genes requires the coordinated expression of class Ⅰ heavy chain. B2-microglobin and numerous components involved in antigen processing and antigen presentating. Downregulation expression of HLA class Ⅰ genes in many carcinomas were observed, but the molecular mechanisms are not clear. The purpose of this study is to investigate the expression of different components of antigen presentation machinery and their involvement in HLA class Ⅰ downregulated expression in human colon carcinoma cell lines. Two colon carcinoma cell lines,LoVo and HT29 with or without prior induction with IFN-γ,were examined the expression of HLA class Ⅰ by flow cytometry. Reverse transcription polymerase chain reaction was performed to assess the expression of class Ⅰ heavy chain, B2-microglobin, proteasome subunits and transporter subunits. Then five pairs of short tandem repeat (STR) microsatellite marker was selected for amplification of HLA class Ⅰ DNA genes region. HLA class Ⅰ genes were expressed normally in HT29, but not in LoVo cells. IFN-γ treatment had no affects on the expression of surface HLA class Ⅰ complex of the LoVo. RT-PCR amplification demonstrated that heavy chain, PA28α, PA28β, TAP1, TAP2, Tapasin genes were lost transcripts in the LoVo, although the DNA of these genes might be intact in this tumor cell line with special primers. All components analyzed were expressed in the HT29. Loss of surface HLA class Ⅰ expression in the LoVo may due to the deficient expression of heavy chain, PA28α, PA28β, TAP1, TAP2, Tapasin.
Colon carcinomas HLA class Ⅰ genes microsatellitemarker
Qin Ye Jianqiong Zhang Fengqing Miao Wei Xie
State Education Ministry Laboratory of Developmental Genes and Human Diseases, Jiangsu Provincial Key Laboratory of Gene Diagnosis and Therapy, Genetics Research Center, Southeast University Medical School, Nanjing 210009, China
国际会议
The 4th International Forum on Post-genome Technologies(4IFPT)(第四届国际后基因组生命科学技术学术论坛)
杭州
英文
513-516
2006-09-25（万方平台首次上网日期，不代表论文的发表时间）