Piechocki M P, Pilon S A, Wei W Z
Karmanos Cancer Institute, Departments of Otolaryngology, and Immunology and Microbiology, School of Medicine, Wayne State University, Detroit, MI 48201, USA.
J Immunol. 2001 Sep 15;167(6):3367-74. doi: 10.4049/jimmunol.167.6.3367.
A plasmid DNA was constructed to encode the N-terminal 505 aa of human ErbB-2 (E2, HER-2/neu) and designated as secreted ErbB-2 (secE2). Recombinant secE2 protein was detected in the transfected cells and was secreted as an 80-kDa glycoprotein. Vaccination of BALB/c mice with secE2 DNA induced both IgG1 and IgG2a ErbB-2-specific Abs and protected approximately 90% of mice against mouse mammary tumor D2F2, which expressed human ErbB-2 (D2F2/E2). The efficacy of secE2 vaccine was comparable with that of wild-type ErbB-2 DNA, which encodes the entire 1258 aa of ErbB-2 protein, induced only IgG2a E2-specific Abs, and stimulated greater CTL activity. Immune lymphocytes were stimulated in vitro with irradiated 3T3 cells, which expressed ErbB-2, K(d), and B7.1. CTL activity was measured by the lysis of E2-positive target cells and by intracellular IFN-gamma production. To enhance CTL activation, mice were immunized with a combination of secE2 and cytoplasmic E2 (cytE2); the latter encodes the 1258-aa ErbB-2 protein that was released into the cytoplasm upon synthesis. Significant increase in CTL activity was demonstrated after mice were immunized with the combined vaccines and all mice were protected from D2F2/E2 tumor growth. Therefore, secE2, which induced Th2 Ab and weak CTL, conferred similar protection as E2, which induced Th1 Ab and strong CTL. Combined vaccination with secE2 and cytE2 resulted in Th2 Ab, strong CTL, and the most effective protection against tumor growth. The strategy of coimmunization with DNA that direct Ags to different subcellular compartments may be adapted as appropriate to optimize immune outcome.
构建了一种质粒DNA，用于编码人ErbB-2（E2，HER-2/neu）的N端505个氨基酸，并命名为分泌型ErbB-2（secE2）。在转染细胞中检测到重组secE2蛋白，并以80 kDa糖蛋白的形式分泌。用secE2 DNA对BALB/c小鼠进行疫苗接种可诱导产生IgG1和IgG2a ErbB-2特异性抗体，并保护约90%的小鼠免受表达人ErbB-2的小鼠乳腺肿瘤D2F2（D2F2/E2）的侵害。secE2疫苗的效果与野生型ErbB-2 DNA相当，后者编码全长1258个氨基酸的ErbB-2蛋白，仅诱导产生IgG2a E2特异性抗体，并刺激产生更强的CTL活性。用表达ErbB-2、K(d)和B7.1的经辐照的3T3细胞在体外刺激免疫淋巴细胞。通过E2阳性靶细胞的裂解和细胞内IFN-γ的产生来测量CTL活性。为增强CTL激活，用secE2和细胞质E2（cytE2）联合免疫小鼠；后者编码合成后释放到细胞质中的1258个氨基酸的ErbB-2蛋白。在用联合疫苗免疫小鼠后，CTL活性显著增加，所有小鼠均受到保护，免受D2F2/E2肿瘤生长的影响。因此，诱导Th2抗体和弱CTL的secE2提供了与诱导Th1抗体和强CTL的E2相似的保护作用。secE2和cytE2联合疫苗接种导致产生Th2抗体、强CTL，并对肿瘤生长提供最有效的保护。将引导抗原至不同亚细胞区室的DNA联合免疫策略可根据需要进行调整，以优化免疫结果。
