| Summary: | 碩士 === 國立清華大學 === 原子科學系 === 90 === Abstract
The aim of this study is to assess the feasibility of treating prostate cancer with the DNA vaccine containing PSA and GM-CSF genes. First, we cloned a DNA plasmid to express the gene of human PSA and the gene of mice GM-CSF simultaneously. Second, we injected this plasmid into C57BL/6J and C3H/HeN mice to evaluate the immunity of different strains of mice. The effect of GM-CSF on DNA vaccine was evaluated by comparing its immunity with the immunity generated by PSA alone.
The results of this study showed that constructed plasmid could not generate humoral immunity against PSA in both strains of mice. There was not difference in IgG1 or IgG2a level following intramuscular DNA vaccine. Western blot was unable to detect the anti-PSA antibody in the serum. However, the CTL assay showed the cytotoxicity of spleen cells from immuned-mice against NFsa-PSA cells. The CTL responses were observed in both strains of mice, which indicated that this response is likely due to the non-specific killing of NK-cells.
The failure of the generation of specific immunity following DNA vaccine could be the results of PSA cloning. Because we found that Nfsa-PSA cells could only express mRNA of PSA as assessed by RT-PCR. We were unable to detect hPSA protein in both the supernatant and cell lysis by ELISA assay. We are currently unaware whether this effect is due to the point mutations of PSA that we cloned or the lack of non-translated regions of PSA gene. A clone of without mutation could be one way to answer this question. Beside, to improve this model, the use of PSA transgenic mice or probasin antigen, which is the prostate specific-antigen of the mouse, is suggested.
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