Expression and immunogenicity of a recombinant chimeric protein of human colorectal cancer antigen GA733-2 and an Fc antibody fragment in stably transformed Drosophila melanogaster S2 cells.

Human colorectal cancer antigen GA733-2 fused to the immunoglobin Fc fragment (GA733-2-Fc) was expressed in stably transformed Drosophila melanogaster S2 cells, and the immunogenicity of recombinant GA733-2-Fc was investigated in mice. Recombinant GA733-2-Fc was secreted into a culture medium with a molecular mass of approximately 65 kDa. Recombinant GA733-2-Fc was purified to homogeneity using affinity fractionation with Protein A sepharose 4 Fast Flow. Recombinant GA733-2-Fc proteins elicited production of specific antibodies against recombinant GA733-2 by immunization through an intraperitoneal route. Recombinant GA733-2-Fc-induced antibodies showed a binding activity to human colorectal carcinoma HCT-116 cells. Secretory recombinant GA733-2-Fc from Drosophila S2 cell systems can be used as an effective experimental antigen for research in cancer vaccine development.