Protection of mice against tumor growth by immunization with an oncogene-encoded growth factor.

The K-fgf/hst oncogene encodes a growth factor of the fibroblast growth factor (FGF) family that is secreted and transforms cells through a mechanism of autocrine cell proliferation. K-fgf-transformed cells are highly tumorigenic in immunocompetent allogeneic and syngeneic animals. BALB/c mice were immunized with a bacterial fusion protein consisting of a portion of the MS2 polymerase and of the human K-FGF precursor lacking only the first 4 amino acids or with a recombinant protein corresponding to the mature, secreted form of K-FGF (176 amino acids). They were then challenged with syngeneic K-fgf- or H-ras-transformed cells. Vaccinated animals exhibited a significant degree of protection against tumor induction, which was specific for K-fgf-transformed cells and correlated with the ability of the immunized mice to produce high titers of anti-K-FGF antibodies. Thus immunization with a single oncogene product can protect animals against tumor cells expressing this oncogene. IMAGES:

K-fgf/hst癌基因编码成纤维细胞生长因子（Fibroblast Growth Factor, FGF）家族的一类分泌型生长因子，可通过自分泌细胞增殖机制转化宿主细胞。经K-fgf转化的细胞在免疫健全的同种异体及同基因动物体内均表现出高度致瘤性。
研究人员采用两种免疫原免疫BALB/c小鼠：一种是由MS2聚合酶部分片段与仅缺失前4个氨基酸的人类K-FGF前体构成的细菌融合蛋白，另一种是对应成熟分泌型K-FGF（含176个氨基酸）的重组蛋白。随后以同基因的K-fgf转化细胞或H-ras转化细胞对免疫小鼠进行攻毒试验。
结果显示，免疫动物对肿瘤发生具有显著的保护作用，该保护作用仅特异性针对K-fgf转化的细胞，且与免疫小鼠产生高滴度抗K-FGF抗体的能力呈正相关。由此可见，仅接种单一癌基因产物即可使动物免受表达该癌基因的肿瘤细胞侵害。
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