Figure 1.

Gene transfer and expression of foreign MHC gene in human melanoma. Size markers (in base pairs) are indicated to the right of each panel. (A) Detection of plasmid DNA in melanoma nodules after direct gene transfer with the DNA–liposome complex. Nucleic acids were isolated from injected nodules and analyzed by PCR (7). Samples were taken at the indicated times, and DNA was extracted according to standard methods (see below). The sensitivity of the PCR analysis is ≈1 copy of recombinant gene per 10⁵ genomes (14). (B) Confirmation of gene expression in tumor nodules transduced by direct gene transfer with HLA-B7. Recombinant HLA-B7 mRNA was detected by using a reverse transcriptase–PCR technique of nucleic acids from biopsy samples. Total RNA was incubated in the presence (+) or absence (−) of reverse transcriptase and analyzed (9). (C) Analysis of blood samples from three patients receiving the highest dose of DNA–liposome complex (300 μg of DNA) before treatment or 5 min after gene transfer as indicated.