L-Theanine Modulates Intestine-Specific Immunity by Regulating the Differentiation of CD4+ T Cells in Ovalbumin-Sensitized Mice

Abstract

Ovalbumin (OVA), a common food protein, can cause deadly allergies with intestine-specific immune reactions. L-Theanine (LTA) shows great potential for regulating intestinal immunity. To investigate the regulatory effect of LTA intervention on intestine-specific immunity, a 41 day experiment was performed on BALB/c OVA-sensitized mice. The results show that injecting female mice intraperitoneally with 50 μg of OVA and administering 30 mg of OVA 4 times can successfully establish an OVAsensitized mouse model. LTA intervention significantly increased weight gain and thymus index (p < 0.05), decreased allergy and diarrhea scores (p < 0.05), and improved jejunum structure. Meanwhile, the histological score and degranulation of mast cells decreased. LTA intervention increased Clostridiales, Lachnospiraceae, Lactobacillus, Prevotella, and Ruminococcus abundance while decreasing Helicobacter abundance. Flow cytometry and Western blotting results indicated that 200 and 400 mg/kg of LTA upregulated the expression of T-bet and Foxp3 proteins (p < 0.05), thus promoting the differentiation of jejunum CD4+ T cells to Th1 and Tregs and increasing the cytokines IFN-γ, IL-10, and TGF-β (p < 0.05). We found that 200 and 400 mg/kg of LTA downregulated the expression of RORγt and GATA3, thus inhibiting the differentiation of Th2 and Th17 cells and decreasing cytokines IL-4, IL-5, IL-13 TNF-α, IL-6, and IL-17A (p < 0.05). LTA inhibited the degranulation of mast cells and significantly decreased the serum levels of OVA-IgE, HIS, and mouse MCPT-1 (p < 0.05). Therefore, LTA intervention alleviated OVA allergy by improving intestine-specific immunity.

Synergistic effects of l-theanine and epigallocatechin gallate in alleviating ovalbumin allergy by regulating intestinal immunity through inhibition of mast cell degranulation

“…According to the conversion coefficient (0.11) of the dosage of mice (20 g) converted to humans (60 kg), the LTA + EGCG dosages used in this study (20 mg kg −1 LTA + 80 mg kg −1 EGCG) could be extrapolated to human dosages (0.22 g per 60 kg green tea), providing a basis for the subsequent development of LTA and EGCG as a functional food. 49…”

l-Theanine attenuates heat stress-induced proteotoxicity and alterations in carbohydrate and lipid metabolismviaheat shock factor 1

“…Evaluation criteria of jejunum damage were performed according to our previous study. 17 Biochemical index measurements. Glucose levels were determined with a blood glucose meter (Roche, Shanghai, China) after overnight fasting.…”

“…However, this was achieved by the anti-oxidation activity. l -Theanine (LTA), the most abundant non-protein amino acid (AA) in tea, is a structural analogue of glutamine, and shows multiple biological activities such as immunomodulation 17 and enhancing cognition. 18 Besides, LTA is effective in regulating nutrient metabolism in normal and stressed organisms.…”

Fish Oil Ameliorates Vibrio parahaemolyticus Infection in Mice by Restoring Colonic Microbiota, Metabolic Profiles, and Immune Homeostasis

“…54 Although supplementation with FO for 14 days did not markedly change the ratio of CD 4+ / CD 8+ , it enriched the CD 4+ T cell numbers in the colon, which secretes immune cytokines IL-10, IFN-γ, and IL-4. 55,56 All of these indicated that acute Vp infection induced a higher abundance of CD 3+ T cells and activated proinflammatory response, whereas presupplementation with 4 mg of FO promoted immune modulation by enhancing CD 4+ T cell proliferation, which in turn increased anti-inflammatory cytokine IL-4 and IFN-γ levels to alleviate Vp-induced inflammation disorder in the gut.…”