[Construction of cDNA library from NPC tissue and screening of antigenic genes]

To obtain the NPC-associated antigens, a powerful new method, SEREX (serological identification of antigen by recombinant cDNA expression library), was used for identifying the antigens eliciting humoral immune response. Before performing serological analysis, a high quality cDNA library derived from human nasopharyngeal carcinoma (NPC) tissue was constructed. The primary library consisted of 3.64 x 10(6) recombinants and the recombinant rate was 94%. For better preserving the cDNA library, it was amplified. As a result, the titer of the amplified cDNA library was 3.8 x 10(9) pfu/mL. With SEREX method, immunoscreening for the detection of reactive clones in the human NPC tissue cDNA library was performed with autologous serum. As a result, 23 positive clones encoding antigenic genes were obtained after immunoscreening, and the nucleotide sequences of cDNA inserts were determined and analyzed with BLAST software in GenBank. Results showed that the 23 reactive clones were derived from 16 different genes. 10 of 16 genes had high homologous to the genes known in GenBank, such as RPL31, S100 A2, MT2A, etc. However, there were also 6 genes with low homology to the genes known in GenBank. Furthermore, 3 of 6 genes may be novel genes. The associations of these genes to NPC and the roles that they played in the occurrence and development of NPC should be revealed by further research.