Institute of Biology and Medical Sciences, School of Biology and Basic Medical Sciences, Soochow University, Suzhou 215123, China.
Department of Laboratory Medicine, The Affiliated Suzhou Hospital of Nanjing Medical University, Gusu School, Nanjing Medical University, Suzhou 215002, China.
J Immunol Res. 2022 Aug 9;2022:8802004. doi: 10.1155/2022/8802004. eCollection 2022.
An endoplasmic reticulum resident protein, calreticulin (CRT), participates in many cellular processes. CRT is a tumor-associated antigen with an important role in antitumor immunity. Previously, we reported that the recombinant CRT fragment 39-272 (CRT/39-272) exhibited superior immunobiological activity, activating macrophages to release cytokines and promoting dendritic cell (DC) maturation. However, the effect of CRT/39-272 , especially its adjuvant effect on antitumor immune responses, was not fully investigated. In this study, we constructed a fusion protein linking CRT/39-272 to an ovalbumin (OVA) peptide (residues 182-297, OVAp) and used the fusion protein (OVAp-CRT) to examine the adjuvant effect of CRT. We investigated whether CRT/39-272 could induce bone marrow-derived DC maturation and strongly promote the proliferation of OVA-specific T cells . Compared with OVAp, OVAp-CRT induced stronger antigen-specific T lymphocyte responses, including antigen-specific T cell proliferation, interferon- secretion, and cytotoxic T lymphocyte responses. OVAp-CRT-immunized mice generated significantly increased OVAp-specific antibody and CD4/CD8 memory T cells, which mediated long-term protective effects. OVAp-CRT upregulated CD40, CD80, and CD86 expressions in splenic conventional DCs. Furthermore, OVAp-CRT protected immunized mice against OVA-expressing B16 melanoma cells . Moreover, mice that were adoptively transferred with OVAp-CRT-pulsed DCs showed inhibited tumor growth and prolonged mouse survival. Our results demonstrate that CRT/39-272 can be used as a potential new adjuvant for tumor vaccines, and this finding may be useful in tumor vaccine development.
内质网驻留蛋白钙网蛋白（CRT）参与许多细胞过程。CRT 是一种肿瘤相关抗原，在抗肿瘤免疫中具有重要作用。先前，我们报道重组 CRT 片段 39-272（CRT/39-272）表现出优异的免疫生物学活性，可激活巨噬细胞释放细胞因子，并促进树突状细胞（DC）成熟。然而，CRT/39-272 的作用，特别是其对肿瘤免疫应答的佐剂作用，尚未得到充分研究。在这项研究中，我们构建了一种将 CRT/39-272 与卵清蛋白（OVA）肽（残基 182-297，OVAp）连接的融合蛋白，并使用该融合蛋白（OVAp-CRT）来研究 CRT 的佐剂作用。我们研究了 CRT/39-272 是否可以诱导骨髓来源的 DC 成熟并强烈促进 OVA 特异性 T 细胞增殖。与 OVAp 相比，OVAp-CRT 诱导了更强的抗原特异性 T 淋巴细胞应答，包括抗原特异性 T 细胞增殖、干扰素分泌和细胞毒性 T 淋巴细胞应答。与 OVAp 免疫的小鼠相比，OVAp-CRT 免疫的小鼠产生了显著增加的 OVAp 特异性抗体和 CD4/CD8 记忆 T 细胞，介导了长期的保护作用。OVAp-CRT 上调了脾常规 DC 中 CD40、CD80 和 CD86 的表达。此外，OVAp-CRT 保护免疫小鼠免受表达 OVA 的 B16 黑色素瘤细胞的侵害。此外，用 OVAp-CRT 脉冲 DC 过继转移的小鼠表现出抑制肿瘤生长和延长小鼠存活时间。我们的结果表明，CRT/39-272 可用作肿瘤疫苗的潜在新型佐剂，这一发现可能对肿瘤疫苗的开发有用。
