***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND The aging process can lead to a decline in cellular immunity . Therefore , the elderly could benefit from safe and effective interventions that restore cellular immune functions . OBJECTIVE We determined whether dietary supplementation with the known immunostimulating probiotic Bifidobacterium lactis HN019 could enhance aspects of cellular immunity in elderly subjects . DESIGN Thirty healthy elderly volunteers ( age range : 63 - 84 y ; median : 69 y ) participated in a 3-stage dietary supplementation trial lasting 9 wk . During stage 1 ( run-in ) , subjects consumed low-fat milk ( 200 mL twice daily for 3 wk ) as a base-diet control . During stage 2 ( intervention ) , they consumed milk supplemented with B. lactis HN019 in a typical dose ( 5 x 10(10 ) organisms/d ) or a low dose ( 5 x 10(9 ) organisms/d ) for 3 wk . During stage 3 ( washout ) , they consumed low-fat milk for 3 wk . Changes in the relative proportions of leukocyte subsets and ex vivo leukocyte phagocytic and tumor-cell-killing activity were determined longitudinally by assaying peripheral blood sample s. RESULTS Increases in the proportions of total , helper ( CD4(+ ) ) , and activated ( CD25(+ ) ) T lymphocytes and natural killer cells were measured in the subjects ' blood after consumption of B. lactis HN019 . The ex vivo phagocytic capacity of mononuclear and polymorphonuclear phagocytes and the tumoricidal activity of natural killer cells were also elevated after B. lactis HN019 consumption . The greatest changes in immunity were found in subjects who had poor pretreatment immune responses . In general , the 2 doses of B. lactis HN019 had similar effectiveness . CONCLUSION B. lactis HN019 could be an effective probiotic dietary supplement for enhancing some aspects of cellular immunity in the elderly Objective : To define the cellular basis for immune enhancement by a probiotic lactic acid bacteria strain ( Bifidobacterium lactis HN019 ) ; and to determine whether immune enhancement can be optimized by delivery in oligosaccharide-enriched low-fat milk . Design : A double-blind , three-stage before- and -after intervention trial . Setting : Taipei Medical College Hospital , Taipei , Taiwan . Subjects : Fifty healthy Taiwanese citizens ( age range 41–81 ; median 60 ) r and omly allocated to two groups . Interventions : In stage 1 ( run-in control stage ) all subjects consumed reconstituted low-fat milk ( LFM ) for 3 weeks ; in stage 2 ( probiotic intervention ) subjects consumed B. lactis in LFM ( group A ) or B. lactis in lactose-hydrolysed LFM ( group B ) for 3 weeks ; in stage 3 all subjects returned to non-supplemented LFM for a further 3 weeks ( washout stage ) . The innate immune functions of two different leucocyte types ( polymorphonuclear ( PMN ) cells and natural killer ( NK ) cells ) were assessed at four time points via in vitro analyses on peripheral blood sample s. Results : While consumption of LFM alone had no significant effect on immune responses , stage 2 results indicated significantly enhanced PMN cell phagocytosis and NK cell tumour killing activity following consumption of milk containing B. lactis . These increases levelled off following cessation of B. lactis consumption , but remained above the pre-treatment values . Increases in PMN and NK cell activity were greatest among subjects who consumed B. lactis in lactose-hydrolysed LFM . Conclusions : Dietary consumption of the probiotic bacterium B. lactis HN019 enhanced immune function of two different types of leucocytes ; the degree of enhancement was increased by consuming B. lactis in an oligosaccharide-rich substrate . Sponsorship : Financial support was provided by the New Zeal and Dairy Board . European Journal of Clinical Nutrition ( 2000 ) 54 , OBJECTIVE The effectiveness of influenza vaccination in preventing illness is lower in the elderly ; this is why the ability of Lactobacillus plantarum CECT 7315/7316 to stimulate the response to  influenza vaccination  in elderly was evaluated . RESEARCH METHODS AND PROCEDURES A r and omized , double-blind , placebo-controlled human trial including 60 institutionalized volunteers aged 65 - 85 years was performed . All the volunteers were vaccinated with a trivalent influenza vaccine ( A/Wisconsin/67/2005 NYMC X-161B ( H3N2 ) , A/Solomon Isl and s/3/2006 ( H1N1 ) and B/Malaysia/2506/2004 ) for the Spanish vaccine campaign 2006/2007 . The consumption of the probiotic began between three and four months after the vaccination . Volunteers were r and omly assigned to one of three following groups : group A ( receiving 5 * 10(9 ) cfu/day of L. plantarum CECT 7315/7316 in 20 g powdered skim milk ) , group B ( receiving 5 * 10(8 ) cfu/day of L. plantarum CECT 7315/7316 in 20 g powdered skim milk ) and group C or placebo ( 20 g powered skim milk ) . The participants consumed the probiotic during 3 months . RESULTS The consumption of L. plantarum CECT 7315/7316 during 3 months after influenza vaccination increased the levels of influenza-specific IgA and IgG antibodies . Moreover , a trend towards an increase in influenza-specific IgM antibodies was also observed . CONCLUSION L. plantarum CECT7315/7316 has an immunostimulating effect and could be used to improve the response to influenza vaccination in elderly Elderly adults have alterations in their gut microbiota and immune functions that are associated with higher susceptibility to infections and metabolic disorders . Probiotics and prebiotics , and their synbiotic combinations are food supplements that have been shown to improve both gut and immune function . The objective of this r and omised , double-blind , placebo-controlled , cross-over human clinical trial was to study immune function and the gut microbiota in healthy elderly adults . Volunteers ( n 37 ) consumed prebiotic galacto-oligosaccharides ( GOS ; 8 g/d ) , probiotic Bifidobacterium lactis Bi-07 ( Bi-07 ; 109 colony-forming units/d ) , their combination ( Bi-07 + GOS ) and maltodextrin control ( 8 g/d ) in four 3-week periods separated by 4-week wash-out periods . Immune function was analysed by determining the phagocytic and oxidative burst activity of monocytes and granulocytes , whole-blood response to lipopolysaccharide , plasma chemokine concentrations and salivary IgA levels . Gut microbiota composition and faecal SCFA content were determined using 16S ribosomal RNA fluorescence in situ hybridisation and HPLC , respectively . Primary statistical analyses indicated the presence of carry-over effects and thus measurements from only the first supplementation period were considered valid . Subsequent statistical analysis showed that consumption of Bi-07 improved the phagocytic activity of monocytes ( P < 0·001 ) and granulocytes ( P = 0·02 ) . Other parameters were unchanged . We have for the first time shown that the probiotic Bi-07 may provide health benefits to elderly individuals by improving the phagocytic activity of monocytes and granulocytes . The present results also suggest that in the elderly , the effects of some probiotics and prebiotics may last longer than in adults Purpose There is growing evidence that probiotics confer health benefits to the host by modulating immune function , especially in older people , where immunosenescence is a feature even of healthy ageing . The aim of this study was to investigate the effect of a probiotic drink containing Lactobacillus casei Shirota ( LcS ) on immune function in a healthy non-immunocompromised older population . Methods Thirty healthy old volunteers were recruited into a r and omized placebo-controlled , single-blind crossover study . The volunteers were supplemented with the probiotic drink containing 1.3 × 1010 CFU LcS or skimmed milk per day for 4 weeks , followed by 4 weeks of washout and were crossed over to the other treatment . Peripheral blood and saliva sample s were collected at baseline and end of each treatment . Results Probiotic consumption was associated with a significant increase in natural killer ( NK ) cell activity relative to baseline and a significant decrease in the mean fluorescence intensity of CD25 expression in the resting T cells compared with placebo . Additionally , there was a trend towards an increased ratio of IL-10 to IL-12 relative to baseline after LcS intake . Conclusions Consumption of a probiotic drink containing LcS  improved NK cell activity and tended to produce a more anti-inflammatory cytokine profile in an older population Faecal and serum sample s were collected over a period of 6 months from 55 institutionalized elderly subjects , who were enrolled in a double-blind placebo-controlled study . Participants were r and omized in one of the three treatment groups : intervention ( two probiotic Bifidobacterium longum strains : 2C and 46 ) , placebo and commercial control ( Bifidobacterium lactis Bb-12 ) . The faecal Bifidobacterium microbiota was characterized by genus and species-specific PCR . Serum levels of the cytokines IL-10 , tumor necrosis factor (TNF)-alpha and transforming growth factor (TGF)-beta1 were determined by enzyme-linked immunosorbent assay . Each participant harboured on average approximately three different bifidobacterial species . The most frequently detected species were B. longum , Bifidobacterium adolescentis and Bifidobacterium bifidum . Depending on the treatment , the intervention result ed in specific changes in the levels of certain Bifidobacterium species , and positive correlations were found between the different species . Negative correlations were observed between the levels of Bifidobacterium species and the pro-inflammatory cytokine TNF-alpha and the regulatory cytokine IL-10 . The presence of faecal B. longum and Bifidobacterium animalis correlated with reduced serum IL-10 . The anti-inflammatory TGF-beta1 levels were increased over time in all three groups , and the presence of Bifidobacterium breve correlated with higher serum TGF-beta1 levels . This indicates that modulation of the faecal Bifidobacterium microbiota may provide a means of influencing inflammatory responses Many elderly subjects are at increased risk of infectious and noninfectious diseases due to an age-related decline in lymphoid cell activity ( immunosenescence ) . Noninvasive means of enhancing cellular immunity are therefore desirable in the elderly . Previous reports have suggested that dietary supplementation could represent an effective means of enhancing the activity of circulating natural killer ( NK ) cells in the elderly . In the present study , we have conducted a pre – post intervention trial to determine the impact of dietary supplementation with probiotic lactic acid bacteria ( LAB ) on peripheral blood NK cell activity in healthy elderly subjects . Twenty-seven volunteers consumed low-fat/low-lactose milk supplemented with known immunostimulatory LAB strains ( Lactobacillus rhamnosus HN001 or Bifidobacterium lactis HN019 ) for a period of 3 weeks . A dietary run-in of milk alone was shown to have no significant effect on NK cells . In contrast , the proportion of CD56-positive lymphocytes in peripheral circulation was higher following consumption of either LAB strain , and ex vivo P BMC tumoricidal activity against K562 cells was also increased . Supplementation with HN001 or HN019 increased tumoricidal activity by an average of 101 and 62 % , respectively ; these increases were significantly correlated with age , with subjects older than 70 years experiencing significantly greater improvements than those under 70 years . These results demonstrate that dietary consumption of probiotic LAB in a milk-based diet may offer benefit to elderly consumers to combat some of the deleterious effects of immunosenescence on cellular immunity BACKGROUND One of the most critical questions in immunosurveillance is whether differences between individuals with regards to natural immunological host defence can predict future development of cancer . Although this question has so far remained open , there are clear indications of significant roles of several naturally cytotoxic lymphocytes in preventing the development of cancer . We began a prospect i ve cohort study among a Japanese general population in 1986 , using various immunological and biochemical markers . METHODS Natural cytotoxic activity  of peripheral-blood mononuclear cells was assessed by isotope-release assay in 3625 residents of a Japanese population mostly older than 40 years of age , between 1986 and 1990 . Immunological and biochemical markers were also measured , and participants were given a question naire on lifestyle . We did an 11-year follow-up survey of the cohort members looking at cancer 
    Output:
    
In conclusion , daily consumption of B. lactis HN019 enhances NK cell and PMN function in healthy elderly adults