Search

Background: 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. Objectives: Therefore, this work aimed to evaluate the molecular-structure adjuvant activity of tannic acid (TA) coupled to a protein antigen in Balb/c mice. Method: 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. Results: 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. Conclusion: 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.

Plants traditionally used for their antiviral activity could be an alternative against SARS-CoV-2. In this study, the efficacy of 10 bioactive plant compounds commonly used in Mexico against COVID-19 was evaluated by molecular docking with two online servers: COVID-19 Docking Server and DockThor. Remdesivir was used as a control. The results showed that Cypellocarpin B, Cypellocarpin C, Luteolin 7-glucoside and Syringetin glucopyranoside showed the highest affinity towards viral proteins Mpro and RdRp respect to Remdesivir. Comparison of molecular docking servers showed differences in the docking motors and proteins available on each server. The use of bioactive compounds represents an alternative for the treatment of patients with COVID-19.

Introduction Diabetes is related to different complications, such as nephropathy. In kidneys, the tight junctions (TJ) regulate the paracellular transport of solutes and water. The claudins are the most significant component in the TJ and are expressed throughout the epithelium and modulated permeability. Objective To evaluate the antioxidant effect of Jatropha dioica (JD) extract and claudin 2 (CLDN 2) in the kidney of rats with induced diabetes. Methods It is an experimental, explanatory, prospective, longitudinal, and analytical study. The effect of hydro-alcoholic extract from JD root on the presence of CLDN 2 in rats with induced diabetes was evaluated. The experiment lasting 21 days, treated 40 rats with and without induced diabetes by an intraperitoneal (IP) injection of alloxan. The study groups were exposed to JD extract at 25, 50, and 100 mg/kg. There was no significant morphological difference in the renal tissue morphology of the treated and control groups. Conclusion These results demonstrate that JD extract at 50 mg/kg ameliorated the tubular damage induced by diabetes, and the mechanism might be related to the CLDN2 expression. Finally, JD could also increase total antioxidant capacity to protect the kidney from oxidative stress.

Background: 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. Objective: 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. Method: 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. Results: 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. Conclusion: 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.