Co-administration ofl-cystine andl-theanine enhances efficacy of influenza vaccination in elderly persons: Nutritional status-dependent immunogenicity
The immune response to influenza vaccine is attenuated in elderly persons, though they are at greatest risk for morbidity and mortality by influenza virus infection. Experimental studies demonstrate that co-administration ofl-cystine andl-theanine enhanced antigen-specific production of immunoglobulin in aged mice infected with influenza virus. We thus investigated the effect ofl-cystine andl-theanine on antibody induction by influenza vaccines in elderly persons. Methods:
Residents in a nursing home were randomly allocated tol-cystine andl-theanine (n = 32) or placebo (n = 33). The test substances were administered p.o. for 14 days before immunization. Serum influenza virus antibody titers were measured before and 4 weeks after vaccination. Results:
Vaccination significantly elevated hemagglutination inhibition (HI) titers for all the three strains of influenza viruses (A/New Caledonia [H1N1], A/New York [H3N2] and B/Shanghai) in both groups. HI titers after vaccination were not significantly different between the two groups for either strain. Also, the seroconversion rate was not significantly different between the two groups in the aggregate. A stratified analysis showed that the rate of seroconversion was significantly greater in thel-cystine andl-theanine group compared with the placebo group for influenza virus A (H1N1) among subjects with low serum total protein (63% vs 10%, P < 0.05) or low hemoglobin (71% vs 9%, P < 0.05). Conclusion:
Co-administration ofl-cystine andl-theanine before vaccination may enhance the immune response to influenza vaccine in elderly subjects with low serum total protein or hemoglobin.
Document Type: Research Article
Affiliations: 1: Department of Internal Medicine, Nagoya Kosein Hospital, Nagoya, 2: Research Institute for Health Fundamentals, Ajinomoto Co., Inc., Tokyo, and 3: Department of Public Health, Osaka City University, Faculty of Medicine, Osaka, Japan
Publication date: December 1, 2008