Boczkowski D, Nair S K, Snyder D, Gilboa E
Department of Surgery, Duke University Medical Center, Durham, North Carolina 27710, USA.
J Exp Med. 1996 Aug 1;184(2):465-72. doi: 10.1084/jem.184.2.465.
Immunization with defined tumor antigens is currently limited to a small number of cancers where candidates for tumor rejection antigens have been identified. In this study we investigated whether pulsing dendritic cells (DC) with tumor-derived RNA is an effective way to induce CTL and tumor immunity. DC pulsed with in vitro synthesized chicken ovalbumin (OVA) RNA were more effective than OVA peptide-pulsed DC in stimulating primary, OVA-specific CTL responses in vitro. DC pulsed with unfractionated RNA (total or polyA+) from OVA-expressing tumor cells were as effective as DC pulsed with OVA peptide at stimulating CTL responses. Induction of OVA-specific CTL was abrogated when polyA+ RNA from OVA-expressing cells was treated with an OVA-specific antisense oligodeoxynucleotide and RNase H, showing that sensitization of DC was indeed mediated by OVA RNA. Mice vaccinated with DC pulsed with RNA from OVA-expressing tumor cells were protected against a challenge with OVA-expressing tumor cells. In the poorly immunogenic, highly metastatic, B16/F10.9 tumor model a dramatic reduction in lung metastases was observed in mice vaccinated with DC pulsed with tumor-derived RNA (total or polyA+, but not polyA- RNA). The finding that RNA transcribed in vitro from cDNA cloned in a bacterial plasmid was highly effective in sensitizing DC shows that amplification of the antigenic content from a small number of tumor cells is feasible, thus expanding the potential use of RNA-pulsed DC-based vaccines for patients bearing very small, possibly microscopic, tumors.
目前，使用特定肿瘤抗原进行免疫接种仅限于少数几种已确定肿瘤排斥抗原候选物的癌症。在本研究中，我们调查了用肿瘤来源的RNA脉冲树突状细胞（DC）是否是诱导细胞毒性T淋巴细胞（CTL）和肿瘤免疫的有效方法。用体外合成的鸡卵清蛋白（OVA）RNA脉冲的DC在体外刺激原发性OVA特异性CTL反应方面比用OVA肽脉冲的DC更有效。用来自表达OVA的肿瘤细胞的未分级RNA（总RNA或聚腺苷酸加尾RNA）脉冲的DC在刺激CTL反应方面与用OVA肽脉冲的DC一样有效。当用OVA特异性反义寡脱氧核苷酸和核糖核酸酶H处理来自表达OVA细胞的聚腺苷酸加尾RNA时，OVA特异性CTL的诱导被消除，这表明DC的致敏确实是由OVA RNA介导的。用来自表达OVA的肿瘤细胞的RNA脉冲的DC接种的小鼠受到保护，免受表达OVA的肿瘤细胞的攻击。在免疫原性差、高转移性的B16/F10.9肿瘤模型中，在用肿瘤来源的RNA（总RNA或聚腺苷酸加尾RNA，但不是聚腺苷酸减尾RNA）脉冲的DC接种的小鼠中观察到肺转移显著减少。从细菌质粒中克隆的cDNA体外转录的RNA在致敏DC方面非常有效，这一发现表明从少量肿瘤细胞中扩增抗原含量是可行的，从而扩大了基于RNA脉冲DC的疫苗对患有非常小的、可能是微小的肿瘤患者的潜在用途。
