Co-expression of granulocyte-macrophage colony-stimulating factor with antigen enhances humoral and tumor immunity after DNA vaccination

Granulocyte-macrophage colony-stimulating factor (GM-CSF) was used to enhance humoral and tumor immunity resulting from DNA immunization. The genes encoding GM-CSF and antigen were cloned onto the same plasmid backbone, but separate promoters drove expression of each gene. beta-Galactosidase was used as the model antigen to generate antibody responses A while the human tumor antigen, MAGE-1. was used to monitor tumor resistance. Immunization with a DNA vaccine co-expressing GM-CSF and beta-gal resulted in higher antigen-specific I-G responses than immunization with antigen encoding plasmid alone or co-inoculated with GM-CSF expressing plasmid. Similarly, DNA vaccines expressing both MAGE-I antigen and GM-CSF were more effective in protecting against B16-MAGE-1 Melanoma. However. both GM-CSF co-expressing DNA vaccines and co-inoculation with plasmids encoding the cytokine or antigen enhanced the generation anti-en-specific IFN-gamma and IL-6 responses. These results demonstrate that co-expressing both GM-CSF and antigen on a DNA vaccine enhances humoral and tumor immune response. (C) 2002 Elsevier Science Ltd. All rights reserved.