To date, dozens of melanoma-associated antigens (MAGEs) have been identified and classified into 2 subgroups, I and II. Subgroup I consists of antigens which expression is generally restricted to tumor or germ cells, also named as cancer/testis (CT) antigen. Proteins and peptides derived from some of these antigens have been utilized in promising clinical trials of immunotherapies for gastrointestinal carcinoma, esophageal carcinoma, pulmonary carcinoma and so on. Various MAGE family members play important physiological and pathological roles during embryogenesis, germ cell genesis, apoptosis, etc. However, little is known regarding the role of MAGE family members in cell activities. It is reasonable to speculate that the genes for subgroup I MAGEs, which play important roles during embryogenesis, could be later deactivated by a genetic mechanism such as methylation. In the case of tumor formation, these genes are reactivated and the resultant proteins may be recognized and attacked by the immune system. Thus, the subgroup I MAGEs may play important roles in the immune surveillance of certain tumor types. Here, we review the classifications of MAGE family genes and what is known of their biological functions.

• Antigens, Neoplasm
• Gastrointestinal Neoplasms/physiopathology
• Humans
• Melanoma-Specific Antigens
• Neoplasm Proteins/physiology
• Nerve Tissue Proteins/physiology
• Nuclear Proteins/physiology

AIM: In order to assess hepatocellular carcinoma associated antigen HCA587 as a potential target for immunotherapy, the Bac-to-Bac expression system was used to express recombinant protein HCA587 in insect cells.

METHODS: The cDNA encoding HCA587 gene was cloned into donor vector pFasBacHtb and recombinant pFasBac Htb-587 was transformed into competent cells DH10Bac. Recombinant Bacmid-587 was transfected into Sf9 insect cells using CELLFECTIN, Recombinant HCA587 protein was produced in Sf9 insect cells after infection with recombinant baculovirus, and was purified using Ni-NTA resin. Sera from HCC patients were also screened using recombinant protein HCA587.

RESULTS: The molecular weight of the recombinant protein HCA587 expressed in insect cells was approximately 43 kd. Western blot results proved the recombinant protein HCA587 had the similar antigenicity with its native counterpart. Serological analysis told that the rate of seroreactivity to HCA587 was not high in HCC patients.

CONCLUSION: The recombinant protein HCA587 was successfully expressed and purified using Bac-to-Bac expression system. It paved the way for generation of specific antibody and investigation of immunohistochemical analysis and immune responses of HCC in the future.

• Animals
• Antigens, Neoplasm/chemistry
• Antigens, Neoplasm/genetics
• Antigens, Neoplasm/isolation & purification
• Base Sequence
• Blotting, Western
• Carcinoma, Hepatocellular/genetics
• DNA Primers
• Electrophoresis, Polyacrylamide Gel
• Humans
• Liver Neoplasms/genetics
• Neoplasm Proteins/chemistry
• Neoplasm Proteins/genetics
• Neoplasm Proteins/isolation & purification
• Recombinant Proteins/chemistry
• Recombinant Proteins/isolation & purification
• Spodoptera
• Transfection