Department of Biochemistry, Biomedical Research Centre, Faculty of Medicine, Universidad Autonoma de Coahuila Unidad Torreon, Torreon, Mexico.
Department of Research, FACSA, Universidad Juarez del Estado de Durango, Gomez Palacio, Mexico.
Protein Pept Lett. 2022;29(2):166-175. doi: 10.2174/0929866528666211125110701.
Immunization or vaccination is the process of inducing artificial immunity against an antigen taking advantage of the mechanisms of immunological memory. Current vaccines include substances known as adjuvants, which tend to improve the immunogenicity of the antigen, reduce the antigen quantity employed, and boost the immune response in weak responders. Unfortunately, only a few vaccine adjuvants are approved for human use.
Thus, the objective of this study was to investigate the effect of Tannic acid on humoral and cell-mediated immunity against bovine serum albumin (BSA) as a protein antigen in Wistar rats.
In order to establish the Tannic acid concentration to test it as an adjuvant, the lethal dose 50 and maximum non-toxic dose were calculated through cytotoxicity and hemolytic assays with J774 A.1 cell line and rat erythrocytes by resazurin reduction method and UV/vis spectrophotometry. Thirty Wistar rats were divided into 5 groups that included two controls without antigen and three treatment groups of adjuvants plus BSA as a protein antigen. The rats were immunized in a 30-day scheme. Blood samples were collected for humoral immunity analysis by means of immunoglobulin quantification, isotyping and antigen-antibody precipitation inhibition analysis. Rat peritoneal macrophages and splenocytes were isolated for cell-mediated immunity analysis by means of nitric oxide quantification from adjuvant stimulated peritoneal macrophages and lymphocytes proliferation assay.
Tannic acid was capable of increasing the immunogenicity of the antigen; besides, it was able to stimulate cell-mediated immunity by means of increased lymphocyte proliferation. Moreover, Tannic acid improved the humoral response by means of increased specific antibodies titers. These activities may be attributed to pattern recognition receptors stimulation.
Tannic acid was considered biocompatible when tested in vivo because the concentration tested did not show cytotoxicity or hemolytic effect, and there was no detrimental effect observed on the animals' health. These results show Tannic acid as a promising candidate for vaccine adjuvant.
免疫接种是利用免疫记忆机制诱导针对抗原的人工免疫的过程。目前的疫苗包括被称为佐剂的物质，这些物质往往可以提高抗原的免疫原性，减少所使用的抗原量，并增强弱应答者的免疫反应。不幸的是，只有少数疫苗佐剂被批准用于人类。
因此，本研究的目的是研究鞣酸对牛血清白蛋白（BSA）作为蛋白质抗原在 Wistar 大鼠中的体液和细胞介导免疫的影响。
为了确定鞣酸作为佐剂的测试浓度，通过 J774A.1 细胞系和大鼠红细胞的细胞毒性和溶血试验，用 RESAZURIN 还原法和 UV/Vis 分光光度法计算致死剂量 50 和最大无毒剂量。将 30 只 Wistar 大鼠分为 5 组，包括 2 组无抗原的对照和 3 组佐剂加 BSA 作为蛋白质抗原的治疗组。大鼠按照 30 天的方案免疫。通过免疫球蛋白定量、分型和抗原抗体沉淀抑制分析采集血液样本进行体液免疫分析。分离大鼠腹腔巨噬细胞和脾细胞，通过佐剂刺激的腹腔巨噬细胞和淋巴细胞增殖试验进行细胞介导免疫分析，定量测定一氧化氮。
鞣酸能够提高抗原的免疫原性；此外，它还能够通过刺激淋巴细胞增殖来刺激细胞介导的免疫。此外，鞣酸通过增加特异性抗体滴度来改善体液反应。这些活性可能归因于模式识别受体的刺激。
在体内测试时，鞣酸被认为是生物相容的，因为测试浓度没有表现出细胞毒性或溶血作用，并且对动物的健康没有观察到不利影响。这些结果表明鞣酸是一种有前途的疫苗佐剂候选物。
