Calreticulin displays in vivo peptide-binding activity and can elicit CTL responses against bound peptides.
Calreticulin displays in vivo peptide-binding activity and can elicit CTL responses against bound peptides.
复制标题
DOI：
10.4049/jimmunol.162.11.6426
复制
发表时间：
1999-06
影响因子：
4.4
通讯作者：
Smita K Nair;P. Wearsch;Duane A. Mitchell;J. J. Wassenberg-J.;Eli Gilboa;C. Nicchitta
中科院分区：
文献类型：
--
作者：
Smita K Nair;P. Wearsch;Duane A. Mitchell;J. J. Wassenberg-J.;Eli Gilboa;C. Nicchitta
钙网蛋白是一种内质网（ER）伴侣，显示凝集素活性，并有助于新生糖蛋白的折叠途径。钙网蛋白还参与将肽组装到新生MHC I类分子上的反应。通过化学和免疫学标准，我们确定钙网蛋白作为肽结合蛋白，并提供数据表明，钙网蛋白可以引发CTL反应，其结合的肽池的组件。在过继性免疫治疗方案中，用从B16/F10.9鼠黑素瘤、E.G7-OVA或EL 4胸腺瘤肿瘤分离的钙网蛋白脉冲的树突状细胞引起对迄今未知的肿瘤衍生的Ag或已知的OVA Ag的CTL应答。为了评价钙网蛋白在引发CTL应答中的相对功效，从B16/F10.9、EL 4和E.G7-OVA肿瘤中平行纯化ER伴侣GRP 94/gp 96、BiP、ERp 72和蛋白质二硫键异构酶，并比较蛋白质引发CTL应答的能力。在B16/F10.9和E.G7-OVA模型中，钙网蛋白在引发CTL应答方面与GRP 94/gp 96一样有效或更有效。BiP、ERp 72和蛋白质二硫键异构酶几乎没有活性。观察到的钙网蛋白的抗原活性在体外实验中被概括，其中观察到用E.G7-OVA衍生的钙网蛋白脉冲骨髓树突细胞引起对OVA特异性CD 8 + T细胞裂解的敏感性。这些数据确定钙网蛋白作为肽结合蛋白，并表明钙网蛋白结合的肽可以重新提交树突状细胞I类分子识别的CD 8 + T细胞。
Calreticulin is an endoplasmic reticulum (ER) chaperone that displays lectin activity and contributes to the folding pathways for nascent glycoproteins. Calreticulin also participates in the reactions yielding assembly of peptides onto nascent MHC class I molecules. By chemical and immunological criteria, we identify calreticulin as a peptide-binding protein and provide data indicating that calreticulin can elicit CTL responses to components of its bound peptide pool. In an adoptive immunotherapy protocol, dendritic cells pulsed with calreticulin isolated from B16/F10.9 murine melanoma, E.G7-OVA, or EL4 thymoma tumors elicited a CTL response to as yet unknown tumor-derived Ags or the known OVA Ag. To evaluate the relative efficacy of calreticulin in eliciting CTL responses, the ER chaperones GRP94/gp96, BiP, ERp72, and protein disulfide isomerase were purified in parallel from B16/F10.9, EL4, and E.G7-OVA tumors, and the capacity of the proteins to elicit CTL responses was compared. In both the B16/F10.9 and E.G7-OVA models, calreticulin was as effective as or more effective than GRP94/gp96 in eliciting CTL responses. Little to no activity was observed for BiP, ERp72, and protein disulfide isomerase. The observed antigenic activity of calreticulin was recapitulated in in vitro experiments, in which it was observed that pulsing of bone marrow dendritic cells with E.G7-OVA-derived calreticulin elicited sensitivity to lysis by OVA-specific CD8+ T cells. These data identify calreticulin as a peptide-binding protein and indicate that calreticulin-bound peptides can be re-presented on dendritic cell class I molecules for recognition by CD8+ T cells.