OBJECTIVE: To evaluate the antitumor effect of mouse immunization with human mucin 1 gene (muc 1) DNA plasmids combined with simultaneous injections of human mucin 1 (MUC1) protein. MATERIALS AND METHODS: MUC1 DNA was cloned in pBK-CMV to prepare DNA plasmids and in pET22b(+) to produce proteins. Three strains of mice, immunized with DNA or DNA plus MUC1, were inoculated with tumor cells obtained from spontaneous tumors. IgG(2a) production, MUC1-specific IFN-delta-producing CD8+ T cells, tumor growth and mouse survival were monitored. RESULTS: Only immunization with DNA plus proteins induced IgG(2a) and intracellular IFN-delta production by CD8+ T cells in the strains tested. DNA plus protein immunization induced a better mouse survival in comparison with the DNA groups. However, all immunized mice invariably developed tumors. CONCLUSION: Immunization with DNA plus proteins induced a better protection from tumor growth than immunization with naked DNA. However, the efficacy of immunization with MUC1-based antigens remains low.
OBJECTIVE: To evaluate the antitumor effect of mouse immunization with humanmucin 1 gene (muc 1) DNA plasmids combined with simultaneous injections of humanmucin 1 (MUC1) protein. MATERIALS AND METHODS:MUC1 DNA was cloned in pBK-CMV to prepare DNA plasmids and in pET22b(+) to produce proteins. Three strains of mice, immunized with DNA or DNA plus MUC1, were inoculated with tumor cells obtained from spontaneous tumors. IgG(2a) production, MUC1-specific IFN-delta-producing CD8+ T cells, tumor growth and mouse survival were monitored. RESULTS: Only immunization with DNA plus proteins induced IgG(2a) and intracellular IFN-delta production by CD8+ T cells in the strains tested. DNA plus protein immunization induced a better mouse survival in comparison with the DNA groups. However, all immunized mice invariably developed tumors. CONCLUSION: Immunization with DNA plus proteins induced a better protection from tumor growth than immunization with naked DNA. However, the efficacy of immunization with MUC1-based antigens remains low.