Title : Improving vaccine response through probiotics and micronutrient supplementation: Evaluating the role of TLR5 in adult female BALB/c mice
Abstract:
The role of probiotics and micronutrients in improving immune system function and response to vaccination has been proven. Hence, this study aimed to investigate the effects of probiotics enriched with micronutrients on the immunogenicity of PastoCovac® vaccine. The probiotic supplement BioBoost® and PastoCovac® vaccine, which contain six expressed receptor-binding domains (RBD) and conjugated with tetanus toxin, were administered concurrently. The safety and efficacy were assessed by determining Immunoglobulin G (IgG) antibody titers to RBD and cytokines, mRNA expression of Toll-like receptors (TLRs) 5, and clinical symptoms. Results revealed that the administration of the probiotics enriched with micronutrients and vitamins for 14 days before the first vaccine dose, followed by continued supplementation for 14 days after the first dose, and in conjunction with the second vaccine dose, yielded the most significant elevation in interleukin 4(IL-4), Tumor Necrosis Factor-alpha (TNF alpha), Interferon-gamma (IFN-gamma), and anti-SARS-CoV-2 RBD IgG levels within the supernatant samples collected from spleen cultures with the highest expression of TLR5 genes in intestinal samples, compared to the control group. Our findings show that taking a supplement containing vitamins, folic acid, zinc, selenium, and probiotics for 14 days before each dose of the PastoCovac® COVID-19 vaccine enhanced immune responses. Short-term use of the supplement (7 days before each dose) also improved immune response compared to the vaccine alone, increasing immunogenicity biomarkers and TLR5 mRNA expression. Thus, TLR5-mediated sensing of probiotics promoted plasma cell differentiation directly and stimulated lymph node macrophages to produce plasma cell growth factors. Using supplements with stimulant effects through the TLR5 innate immune pathway seems to be a helpful method for improving fragile immune responses in elderly persons after vaccination. This suggests that probiotic supplements could be beneficial for boosting immune responses, especially for immunodeficient and elderly individuals receiving third and fourth vaccine doses.
