ABSTRACT
In order to reduce its immunogenicity and increase its therapeutic usefullness, the murine anti-gastric cancer McAb 3H11 was genetically engineered into a human-mouse chimeric antibody. The 3H11 light and heavy chain variable genes were inserted into chimeric antibody expression vectors respectively. The chimeric light chain expression vector was first transfected into murine Sp2/0 myeloma cells using lipofectin. Transfectants that stably expressed human-mouse chimeric light chain were isolated by mycophenolic acid selection. Then the chimeric heavy chain expression vector was transfected into the transfectomas. Histidinol resistent cells were obtained and among these, clones stably secreting human-mouse chimeric antibodies were selected. The expression of human-mouse chimeric light and heavy chain mRNAs were proved by RT-PCR and the expressed chimeric antibody was demonstrated capable of binding to human gastric cancer cell MGC803