恶性疟原虫重组质粒DNA接种诱导BALB/c小鼠的免疫应答

目的：观察重组质粒DNA直接免疫接种诱导BALB／c小鼠的免疫应答水平，为恶性疟原虫DNA疫苗在动物和人体的应用提供依据。方法：构建编码多价保护性抗原的重组质粒pcDNA3－Pf8，PCR法检测免疫鼠的肌肉、肝脏、肾脏、心脏、脾脏和肺组织中pcDNA3－Pf 8，ELISA、T淋巴细胞转化试验、体外抑制试验观察其诱导的体液免疫及细胞免疫水平。结果：用PCR法从上述组织中均检测到pcDNA3－Pf8，ELISA法测得免疫鼠血清的特异性抗体滴度达12560，淋巴细胞转化试验显示恶性疟原虫可溶性抗原能特异性地剌激免疫鼠脾细胞增殖，免疫血清在体外还能抑制恶性疟红内期疟原虫的生长、发育。结论：编码恶性疟原虫多价保护性抗原的重组质粒pcDNA 3-Pf 8 直接免疫接种, 能特异性地剌激BALB/c 小鼠产生体液免疫和细胞免疫应答, 其免疫血清在体外对疟原虫生长发育具有明显抑制作用。

DNA VACCINE OF PLASMODIUM FALCIPARUM:IMMUNE RESPONSE OF BALB/c MICE INDUCED BY INJECTION OF THE RECOMBINANT PLASMID DNA

AIM: To observe the level of immune responses of BALB/c mice induced by direct injection of the recombinant plasmid DNA and to provide evidence for the application of DNA vaccine of Plasmodium falciparum (P. f.) in animals and humans. METHODS: The recombinant plasmid pcDNA3-Pf8 encoding the hybrid antigens of PfCMR-MSP1(19) was constructed. The presence of Pf8 plasmid was detected in the muscle, liver, kidney, heart, spleen and lung by PCR. ELISA, T lymphocyte transformation test, inhibitory assay of the growth and development of P. f. in vitro were used to determine the level of humoral and Th-cell responses. RESULTS: pcDNA3-Pf8 was amplified by PCR technique in the different tissues from BALB/c mice which were injected with pcDNA3-Pf8. The immune serum was specifically recognized by the soluble antigens of P. falciparum (titer: 1:2,560 by ELISA). The specific proliferative response of spleen T cells from immunized mice was remarkably higher than that of control group, the transformation rate being up to 32.82 +/- 3.64%. The immune serum could also inhibit the growth and development of the erythrocytic stages of P. falciparum in vitro. CONCLUSION: Direct injection with the recombinant plasmid pcDNA3-Pf8 specifically elicits BALB/c mice to generate humoral and cell-mediated immune responses, the resulting immune serum being inhibitory to the growth and development of P. f. in vitro.