Abstract:  Objective To  clone,  express  and  purify  C17orf77  recombinant  protein  for preparation of specific polyclonal antibody and to determine the expression of C17orf77 protein in different cell lines, and further elucidate its biological function. Methods PCR was applied to amplify the gene C17orf77 in vitro. pET-32a (＋)-C17orf77, the recombinant protein prokaryotic expression vector, was transformed into E. coli. Then IPTG was taken as the inductive agent to obtain C17or77 recombinant protein, which was analyzed by the recombinant protein with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot. Specific polyclonal antibody was derived from rabbits immunized by recombinant protein. ELISA and Western blot were applied to test its titer and specificity, respectively. MTT cell proliferation experiment was carried out to observe the effects of different concentration of recombinant protein on proliferation of HepG2 cells. Western blot was used to observe the expression of C17orf77 protein in HepG2, L02, LX2 and Jurkat cells, respectively. Results The C17orf77 recombinant protein was expressed in a large quantity. Data of ELISA indicated that the titer of polyclonal antibody was higher than 1∶1 280 000. And the antibody also had a good specificity, which was confirmed by Western blot. C17orf77 recombinant protein had no impact on the proliferation of HepG2 cells (P ＞ 0.05). C17orf77 protein could be observed in all HepG2, L02, LX2 and Jurkat cell lines. Conclusions Through C17orf77 recombinant protein, we can prepare the polyclonal antibody with great titer and good specificity. Human novel gene C17orf77 expresses in HepG2, L02, LX2 and Jurkat cells at different level, suggesting that it may participate in the pathogenic processes of HBV infection related diseases.