Department of Biochemistry, Biomedical Research Centre, Faculty of Medicine, Universidad Autonoma de Coahuila, Unidad Torreon, Torreon, Mexico.
Department of Pharmacology, Faculty of Medicine, Universidad Autonoma de Coahuila, Unidad Torreon, Torreon, Mexico.
Protein Pept Lett. 2022;29(11):925-936. doi: 10.2174/0929866529666220902152147.
An antigen is a small foreign substance, such as a microorganism structural protein, that may trigger an immune response once inside the body. Antigens are preferentially used rather than completely attenuated microorganisms to develop safe vaccines. Unfortunately, not all antigens are able to induce an immune response. Thus, new adjuvants to enhance the antigen's ability to stimulate immunity must be developed.
Therefore, this work aimed to evaluate the molecular-structure adjuvant activity of tannic acid (TA) coupled to a protein antigen in Balb/c mice.
Bovine serum albumin (BSA) was used as an antigen. The coupling of BSA and TA was mediated by carbodiimide crosslinking, and verified by SDS-PAGE. Forty-two Balb/c mice were divided into seven groups, including two controls without antigen, an antigen control, an adjuvant control, and two treatment groups. An additional group was used for macrophages isolation. A 30-day scheme was used to immunize the mice. The analysis of humoral immunity included immunoglobulin quantification, isotyping and antigen-antibody precipitation. The analysis of cell-mediated immunity included the quantification of nitric oxide from peritoneal macrophages and splenocytes' proliferation assay after treatment stimulation.
No differences were found in the antibodies' concentration or isotypes induced with the conjugate or the pure BSA. However, an immunogenicity improvement (p < 0.05) was observed through the specific anti-BSA antibody titers in mice immunized with the conjugate. Besides, macrophage activation (p < 0.05) was detected when stimulated with the treatments containing TA.
Tannic acid exhibited macrophages' activation properties. Moreover, when TA was incorporated into the structure of a protein antigen, such as BSA, an antibody specificity enhancement was observed. This was a consequence of antigen processing by activated antigen-presenting cells. These results showed the use of tannic acid as a novel candidate for vaccine molecular-structure adjuvant.
抗原是一种小分子的外来物质，如微生物结构蛋白，一旦进入体内就可能引发免疫反应。抗原被优先用于开发安全疫苗，而不是完全减毒的微生物。不幸的是，并非所有抗原都能诱导免疫反应。因此，必须开发新的佐剂来增强抗原刺激免疫的能力。
因此，本工作旨在评估单宁酸（TA）与蛋白质抗原结合后作为分子结构佐剂在 Balb/c 小鼠中的活性。
牛血清白蛋白（BSA）被用作抗原。通过碳二亚胺交联介导 BSA 与 TA 的偶联，并通过 SDS-PAGE 验证。将 42 只 Balb/c 小鼠分为 7 组，包括 2 个无抗原的对照、1 个抗原对照、1 个佐剂对照和 2 个治疗组。另外一组用于分离巨噬细胞。采用 30 天方案免疫小鼠。体液免疫分析包括免疫球蛋白定量、分型和抗原抗体沉淀。细胞介导的免疫分析包括刺激后腹腔巨噬细胞和脾细胞增殖试验中一氧化氮的定量。
用缀合物或纯 BSA 免疫的小鼠中抗体浓度或同种型无差异。然而，与单独的 BSA 相比，用缀合物免疫的小鼠中观察到特异性抗-BSA 抗体滴度的免疫原性提高（p<0.05）。此外，当用含有 TA 的处理物刺激时，检测到巨噬细胞的激活（p<0.05）。
单宁酸具有激活巨噬细胞的特性。此外，当 TA 被整合到蛋白质抗原（如 BSA）的结构中时，观察到抗体特异性增强。这是由于激活的抗原呈递细胞对抗原的加工。这些结果表明单宁酸可用作疫苗分子结构佐剂的新型候选物。
