Enhancement of Antigen-Specific Immunoglobulin G Production in Mice by Co-Administration of L-Cystine and L-Theanine

Abstract

ABSTRACT. Supplementation with both cystine and glutamic acid increases the synthesis of glutathione (GSH), which has a marked effect on immune cell function, as compared with supplementation with either amino acid alone in human macrophages in vitro. As dietary glutamic acid is metabolized during intestinal transport, oral administration of L-theanine (γ-glutamylethylamide), which is metabolized to glutamic acid mainly in the liver, may act as a glutamic acid donor in vivo. The present study was performed to investigate the effects of oral administration of L-cystine and/or L-theanine on GSH levels and immune responses. Co-administration of L-cystine (200 mg/kg) and L-theanine (80 mg/kg) for 11 days before immunization significantly increased the levels of total GSH in the liver 6 hr after immunization as compared with the levels in control mice. To examine the effects of administration of L-cystine and/or L-theanine on the balance of T helper (Th) 1/Th2 cell responses, the serum ratios of the Th1 cytokine, interferon (IFN)-γ, and the Th2 cytokine, interleukin (IL)-10, were investigated. At 24 hr after immunization, co-administration significantly increased the IL-10/IFN-γ ratio compared with the ratios of the control and single-administration mice. Furthermore, co-administration before primary immunization significantly enhanced serum antigen-specific IgG levels. Taken together, these findings suggest that co-administration of L-cystine and L-theanine enhances antigen-specific IgG production partly through augmentation of GSH levels and Th2-mediated responses.

Combined Administration L-Cystine and L-Theanine Enhances Immune Functions and Protects against Influenza Virus Infection in Aged Mice

“…L -Cystine and L -theanine enhanced the antigen-specific anti-DNP IgM and IgG antibody titers in the serum at a lower dose (16 mg/kg) in 24-month-old C3H/HeN mice than in 12-week-old BALB/c mice (280 mg/kg) [22]. Franklin et al have reported that the peak GSH-induced proliferation is consistently fourfold greater in splenocytes from old rats as compared to young rats when cells are stimulated with concanavalin A.…”

“…Previously, we reported that combined oral administration of L -cystine and L -theanine induces significant enhancement of antigen-specific anti-DNP IgG antibody production in 12-week-old BALB/c mice [22]. It has been reported that antigen-specific anti-DNP IgG antibody production in female C3H/HeN mice decreases with age [35].…”

“…In addition, GSH levels and the gene expression of -glutamylcysteine synthetase (GCS), the rate-limiting enzyme in GSH synthesis, are known to decrease with aging [24]. These results suggest that GSH antioxidant therapy may aid in preventing or delaying the onset of age-related immune impairment.A recent study we performed indicated that combined administration of L -cystine and L -theanine (-glutamylethylamide, a specific amino acid found in green tea) to young mice increases the GSH level in the liver and also enhances the serum antigen-specific IgG antibody level in comparison with those of control mice [22]. Administration of either L -cystine or L -theanine alone has no significant effect.…”

“…A recent study we performed indicated that combined administration of L -cystine and L -theanine (-glutamylethylamide, a specific amino acid found in green tea) to young mice increases the GSH level in the liver and also enhances the serum antigen-specific IgG antibody level in comparison with those of control mice [22]. Administration of either L -cystine or L -theanine alone has no significant effect.…”

“…All serum samples were stored at -80C until analysis. The levels of anti-DNP IgM and IgG antibodies were evaluated as described previously [22]. The antibody titer was defined as the dilution rate calculated from the intercept and slope of the measured value of each dilution sample at the optimal optical density.…”