Heat-killed Lactobacillus gasseri can enhance immunity in the elderly in a double-blind, placebo-controlled clinical study

Abstract

This double-blind, placebo-controlled clinical trial was conducted to test whether Lactobacillus gasseri TMC0356 (TMC0356) can modify the immune response in the elderly. Heat-killed TMC0356 or placebo was orally administered to 28 healthy subjects aged 50-70 years old for 4 weeks at a dosage of 1.0×10(9) cfu/day. Peripheral blood mononuclear cells (PBMCs) were collected from the subjects before and after the study completion, together with general health and blood examination records. Isolated PBMCs were examined for the number of T cells, CD8(+)CD28(+) cells, native T cells, B cells, natural killer (NK) cells and the ratios of CD4/CD8 T cells and native/memory T cells. NK cell activation and concanavalin A-induced lymphocyte transformation of the isolated PBMCs were also examined. The number of CD8(+) T cells significantly increased in the subjects after TMC0356 oral administration (P<0.05). Furthermore, the population of CD8(+)CD28(+) T cells and the amount of lymphocyte transformation both significantly decreased in PBMCs from the placebo group (P<0.05). However, such changes were not observed in the subjects exposed to TMC0356. These results suggest that TMC0356 can increase the number of CD8(+) T cells and reduce CD28 expression loss in CD8(+) T cells of the elderly. The effect of TMC0356 on immune responses in the elderly may enhance their natural defence mechanisms against pathogenic infections.

The Effect of Bifidobacterium animalis ssp. lactis HN019 on Cellular Immune Function in Healthy Elderly Subjects: Systematic Review and Meta-Analysis

“…A combination of L. rhamnosus HN001 and L. acidophilus NCFM resulted in a significantly increased cytotoxicity of the NK cells [39] . In contrast, B. longum BB536 intake for 12 weeks had no effect on NK cell activity in elderly patients fed by enteral tube feeding [40] and L. gasseri TMC0356 supplementation for 4 weeks had no significant impact on NK cell counts or NK cell activity [41]. Altogether three studies have assessed the effect of L. casei Shirota on NK cell function: (i) Takeda and colleagues showed that L. casei Shirota may elevate NK cell activity after 4 weeks when compared to placebo [42]; (ii) the consumption of L. casei Shirota was associated with a significant increase in NK cell activity relative to baseline, however the difference was not significant when compared with placebo [43]; and (iii) a study showed that NK-cell activity was not significantly augmented by a 3-week intake of L. casei Shirota [44].…”

Effect of Daily Intake of Heat-Killed Lactobacillus plantarum HOKKAIDO on Immunocompetence: A Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Study

“…Previous studies have suggested that for demonstrating the effect of probiotics, the intervention period should be >2 weeks [27][28][29]. Accordingly, it is suggested that at least 4 weeks of intake is necessary for observing the immunostimulatory effect of the HK-HOKKAIDO strain.…”

Pretreatment with a heat-killed probiotic modulates monocyte chemoattractant protein-1 and reduces the pathogenicity of influenza and enterovirus 71 infections

“…It is noteworthy that heat-killed and not live bacteria were used for this study. In addition, considerable clinical evidence has indicated that dead probiotic bacteria can improve health for many patients, including elderly people, 8 adult atopic dermatitis patients, 9 and such bacteria reduce the incidence of infection in people with high levels of psychological stress. 11 Previous research suggests that the immune responses elicited by probiotics may differ according to the growth phase (i.e., logarithmic vs. stationary) and may differ depending on the use of live vs. heat-killed bacteria.…”

“…5 Studies have demonstrated that heat-killed probiotics are safer than live probiotics for purposes such as eliminating antibioticresistant genes, preventing production of recombinant strains, controlling the microbial load during probiotic supplementation, and application in children and immunosuppressed patients. 6,7 Furthermore, considerable clinical evidence has indicated that dead probiotic bacteria can improve health; for example, they can enhance immunity in elderly people; 8 they have benefits as a complementary therapy for adult atopic dermatitis patients receiving the conventional treatment; 9 they can effectively improve the overall quality of life for patients with allergic rhinitis; 10 and they reduce the incidence of upper respiratory tract infection in healthy people with high levels of psychological stress. 11 Specifically, it has been previously reported that oral administration of lysed E. faecalis to mice can reduce both the allergen-induced peritoneal accumulation of eosinophils 12 and the serum ratio of allergen-specific IgE to IgG2a antibodies.…”