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Nutritional Immunology

Impaired Dendritic Cell Function Resulting from Chronic Undernutrition Disrupts the Antigen-Specific Immune Response in Mice¹

Department of Gastroenterology and Metabology, Ehime University Graduate School of Medicine, Toon, Japan 791-0295

^* To whom correspondence should be addressed. E-mail: akbar{at}m.ehime-u.ac.jp.

	ABSTRACT

TOP ABSTRACT Introduction Materials and Methods Results Discussion LITERATURE CITED

 
We examined whether antigen-specific immune responses are lower in mice with protein energy malnutrition (PEM mice) compared with nourished (control) mice. The mechanisms underlying reduced antigen-specific immune responses of PEM mice were evaluated through analysis of the functional capacities of antigen-presenting dendritic cells (DC). PEM mice were produced by subjecting male C57BL/6 mice for 52 wk to a daily food intake equivalent to 70% of the mean amount consumed by the control mice that consumed food ad libitum. PEM mice and control mice were immunized with hepatitis B vaccine containing hepatitis B surface antigen (HBsAg) at 52 wk and humoral and cellular immune responses to HBsAg were evaluated at 58 wk. Lymphoproliferative assays were performed to assess the functional capacities of lymphocytes and DC. After 52 wk of food restriction, PEM mice had a 49% lower body weight than controls, almost no subcutaneous fat, severe muscle wasting, and atrophied spleen. All control mice developed antibodies to HBsAg (anti-HBs) in the sera and HBsAg-specific lymphocytes in the spleen as a result of immunization with the hepatitis B vaccine. PEM mice, however, were almost unresponsive to immunization with the hepatitis B vaccine. In PEM mice, the numbers of spleen DC, the T lymphocyte stimulatory capacities of DC, and their production of IL-12p70 and IFN- was less than those of control mice (P < 0.05). We suggest that chronic undernutrition disrupts antigen-specific immune responses and that this disruption can be attributed at least in part to reduced frequencies and impaired functions of DC.

	Introduction

TOP ABSTRACT Introduction Materials and Methods Results Discussion LITERATURE CITED

In this context, investigators have shown that the functional capacities of different immunocytes decrease in subjects with nutritional deficiencies (9–13). However, some have reported that the proliferative capacities of T and B lymphocytes either remain unaltered or increase in subjects under dietary restriction (14–16). These discrepancies regarding the impact of nutrition on the function of T and B lymphocytes may be attributable to differences in experimental design and analytic procedures. In addition, some important aspects about the impact of nutrition on immune responses have not been well addressed. Most studies of nutrition and immune responses have mainly evaluated the effect of dietary restriction on lymphocyte proliferation in response to nonspecific stimulants (mitogenic stimulation). Although antigen-specific immune responses are critical for host protection, there is a paucity of information regarding antigen-specific immune responses in chronically undernourished subjects. To test properly the effect of nutrition on immune responses, experiments should incorporate both in vivo and in vitro approaches. Yet, most investigators use only one of these approaches in subjects with dietary restriction.

Although T and B lymphocytes represent effector cells of the immune system, the functional capacities of lymphocytes, especially the induction and functions of antigen-specific lymphocytes, are regulated by antigen-presenting dendritic cells (DC)² (17). DC are present in almost all tissues and can recognize, capture, process, and present microbial agents and different types of antigens (18). We and others have recently demonstrated that impaired functional capacities of DC are related to the pathogenesis of a chronic viral carrier state and activation of DC in these subjects has therapeutic potential (19,20). However, little is known regarding the impact of nutrition on frequencies and functions of DC and on antigen-specific immune responses. Therefore, in this study, we first evaluated the magnitude of antigen-specific humoral and cellular immune responses in a murine model of protein energy malnutrition (PEM) and in control mice by immunizing them with the hepatitis B vaccine. Next, we compared the frequencies and functions of DC in PEM and control mice to gain insights into the mechanism underlying the impaired antigen-specific immune responses of PEM mice.

	Materials and Methods

TOP ABSTRACT Introduction Materials and Methods Results Discussion LITERATURE CITED

 
    Mice. Eight-wk-old male C57BL/6 mice were purchased from Nihon Clea. The mice were housed individually in polycarbonate cages in a temperature-controlled room (23 ± 1°C) with a 12-h–light/-dark cycle at the Ehime University animal facility. Mice were fed a commercial laboratory chow (Oriental Corporation). Approximately 100 g of the nonpurified diet contained 23.6 g protein, 5.3 g fat, 6.1 g ash, 2.9 g fiber, and 54.4 g nitrogen-free extracts. All mice received humane care and the study protocol was approved by the Ethical Committee of the Graduate School of Medicine, Ehime University, Japan.

    Preparation of PEM mice. The food consumed by 1 adult C57BL/6 mouse per day was calculated by keeping 11 normal C57BL/6 mice separately (1 mouse per cage) and allowing them to consume food ad libitum for 12 wk. The mean daily intake was 2.68 g. Then, we produced 2 groups of mice. The control mice (n = 25) were housed in individual cages and consumed food ad libitum (2.7–3.0 g/d) for 52 wk. PEM mice (n = 25) were housed individually and received 1.7–1.9 g food/d for 52 wk. This was 70% of that consumed by control mice. We measured body weights of all mice once each week. Blood samples were taken at regular intervals and the serum concentrations of total protein (A/G B-Test, Wako), total albumin (A/G B-Test, Wako), and total cholesterol (Cholesterol E Test Wako kit) were measured using commercial kits (Wako, Osaka, Japan). The numbers of leukocytes and lymphocytes were estimated at weekly intervals for the first 4 wk and then at monthly intervals for the next 52 wk. Some control (n = 5) and PEM mice (n = 5) were killed after 52 wk to determine the weights of different organs and body fat depots. Other mice (n = 20) were used for immunization with hepatitis B vaccine and for isolation of T lymphocytes, B lymphocytes, and DC.

    Immunization with hepatitis B vaccine containing hepatitis B surface antigen. After 52 wk of treatment, control mice and PEM mice of the same age were immunized with a commercially available hepatitis B vaccine containing hepatitis B surface antigen (HBsAg) (Heptavax-II, subtype adw, Banyu Pharmaceutical). The levels of antibodies to HBsAg (anti-HBs) in the sera were measured 4 and 6 wk after immunization by chemiluminescence enzyme immunoassay method (Special Reference Laboratory) and were expressed as IU/L, as described previously (21). After immunization at 52 wk, control mice continued to consume food ad libitum (2.7–3.0 g/d) and PEM mice ate 1.7–1.9 g food/d.

    Isolation of T lymphocytes, B lymphocytes, and DC from spleen. Fifty-two wk after study commencement, control mice and PEM mice were anesthetized with diethyl ether and killed by cervical dislocation. The spleens were removed aseptically, cut into pieces, and incubated at 37°C in 5% CO₂ for 30 min in RPMI 1640 (Nipro) supplemented with 1 g/L collagenase (type IV, Sigma Chemical). The tissue was then forced through a sterile stainless steel wire screen (25 µm, Morimoto Yakuhin) and a single-cell suspension of spleen was produced, as described previously (22,23). T lymphocytes and B lymphocytes were isolated from the single cell suspension of spleen, as previously described (24). Briefly, T lymphocytes were purified from single cell suspensions of spleen by a positive-selection column method (Miltenyi Biotec). B cells were isolated using a B cell isolation kit according to manufacturer's instructions (Miltenyi Biotec).

Spleen DC were isolated, as described previously (20–23). Briefly, single-cell suspensions of spleen were centrifuged at 10,000 x g; 30 min on a dense albumin column (specific gravity, 1.082) at 4°C and then cultured for 90 min at 37°C on a plastic surface. The adherent cells were cultured for an additional 18 h in culture medium containing RPMI 1640 (Iwaki) plus 10% fetal calf serum (Filtron PTY). Macrophages were depleted from the DC population by 2 additional adherent steps on plastic dishes at 37°C.

    HBsAg-specific memory lymphocytes. HBsAg-specific memory lymphocytes were prepared, as described previously (20,25). Briefly, 8-wk-old male C57BL/6 mice were immunized twice with 10 µg of HBsAg in adjuvant at an interval of 4 wk. Serial evaluation revealed that at 7–8 mo after immunization, HBsAg-specific lymphocytes in these mice were in a memory state, because these lymphocytes proliferated after stimulation with DC and HBsAg but not with HBsAg only.

    Preparation of HBsAg-pulsed DC. Based on data from previous studies (26), we cultured mouse spleen DC (1 million) in 1.0 mL of RPMI 1640 plus 10% fetal calf serum with 100 µg of HBsAg (Institute of Immunology) for 48 h. DC were recovered from the cultures and washed 5 times with PBS. The final wash solution was preserved to assess whether free HBsAg was present in HBsAg-pulsed DC.

    Lymphoproliferative assays. We conducted a series of experiments to optimize the protocols for the lymphocyte proliferation assays, as described previously (20–26). T lymphocytes and B lymphocytes were cultured with concanavalin A (Sigma Chemical) and LPS (Sigma Chemical), respectively, for 72 h.

Lymphocytes were isolated from control mice and PEM mice that had been immunized with hepatitis B vaccine. These lymphocytes were cultured in the absence or presence of HBsAg (1 mg/L) for 120 h to evaluate HBsAg-specific cellular immune responses.

We evaluated the stimulatory capacities of DC to induce proliferation of HBsAg-specific memory lymphocytes by culturing HBsAg-specific memory lymphocytes and DC from control mice and PEM mice without or with HBsAg (1 mg/L) for 120 h.

We assessed the functional capacities of HBsAg-pulsed DC by culturing HBsAg-specific memory lymphocytes and HBsAg-pulsed DC for 120 h.

All cultures were performed in 96-well U-bottom plates (Corning). [³H]-thymidine (1.0 mCi/L, Amersham Biosciences UK) was diluted in sterile PBS and added to the cultures. Cells were then maintained under these conditions for an additional 16 h and harvested automatically by a multiple cell harvester (LABO MASH, Futaba Medical) onto a filter paper (LM 101–10, Futaba Medical). The paper discs that contained the labeled cells were added to vials containing 5 mL of aqueous counting scintillant (ACS II, Amersham Biosciences). The levels of incorporation of ³[H]-thymidine were determined in a liquid scintillation counter (Beckman-LS 5000, Beckman Instruments) from the levels of blastogenesis. The data were expressed as Bq.

    Estimation of IL-12p70 and IFN-. The levels of IL-12p70 and IFN- in culture supernatants were estimated using a commercial kit for the cytometric bead array method, as described (24). The levels of cytokines in the culture supernatants were calibrated from the mean fluorescence intensities of the standard negative control, standard positive control, and samples by Cytometric Bead Array software (BD Biosciences) using a Macintosh computer (SAS Institute).

    Statistical analysis. Repeated measures ANOVA were conducted to test time and diet effects, and time and leukocyte and lymphocyte counts. An appropriate post hoc test (Dunnett's test or Student-Newman-Keuls test) was applied to determine which groups differed. Other data were analyzed by unpaired t tests if the data were normally distributed and by the Mann-Whitney rank-sum test if they were skewed. Differences were considered significant if P < 0.05. Data are shown as means ± SEM.

	Results

TOP ABSTRACT Introduction Materials and Methods Results Discussion LITERATURE CITED

 
    Characteristics of PEM mice. The body weights of control mice (23.73 ± 0.27 g, n = 25) and PEM mice (23.12 ± 0.31 g, n = 25) did not differ before the study began. Body weights of control mice increased 24% to 31.6 ± 0.4 g. On the other hand, the body weight of PEM mice decreased by 25% to 17.6 ± 0.4 g (Fig. 1). Serum cholesterol concentrations were lower in PEM mice at wk 52 (12.4 ± 0.26 mmol/L, n = 10) compared with their baseline value (20.7 ± 1.09 mmol/L, n = 10) (P < 0.05). Visceral fat, subcutaneous fat, and spleen weights were significantly lower in PEM mice compared with those of control mice (Table 1). The relative spleen and fat weights (g/100 g body weight) also were lower in PEM mice compared with control mice (P < 0.05).

View larger version (10K): [in this window] [in a new window]   Figure 1  Body weights of control and PEM mice throughout the study. Values are means ± SEM, n = 25. Control mice and PEM mice differed beginning at wk 1.

View larger version (10K): [in this window] [in a new window]   Figure 2  Numbers of leukocytes (A) and lymphocytes (B) in the peripheral blood of PEM mice (n = 10). Values are means ± SEM, n = 10. *Different from d 0, P < 0.05.

    HBsAg-specific cellular immune responses. Lymphocytes from PEM mice and control mice, immunized with hepatitis B vaccine containing HBsAg, were cultured with HBsAg to assess HBsAg-specific cellular immune responses. The proliferation of HBsAg-specific lymphocytes from PEM mice (119.4 ± 12.4) was less than in control mice (395 ± 68 Bq) (P < 0.05).

    Proliferative capacities of lymphocytes to polyclonal mitogens. A total of 2 x 10⁵ each of T and B lymphocytes from PEM mice and control mice were cultured with concanavalin A (1 g/L) and LPS (10 g/L), respectively, for 72 h. The levels of blastogenesis of cultures containing T lymphocytes from control mice (624.7 ± 99.7 Bq) and PEM mice (645 ± 72.8 Bq) did not differ nor did levels in culture containing B lymphocytes, where the values were 139.4 ± 12.6 Bq and 140.4 ± 24.7 Bq, respectively.

    Functional capacities of spleen DC. Because antigen-specific humoral and cellular immune responses were impaired in PEM mice, we investigated the underlying mechanism by analyzing the frequencies and functional capacities of spleen DC. The numbers of spleen DC were significantly lower in PEM mice compared with control mice (Table 2). Spleen DC from both PEM and control mice were challenged to stimulate HBsAg-specific memory lymphocytes in the presence of HBsAg. Spleen DC from PEM mice had reduced capacities to stimulate HBsAg-specific memory lymphocytes compared with spleen DC from control mice (P < 0.05) (Fig. 3).

View larger version (9K): [in this window] [in a new window]   Figure 3  Capacities of spleen DC from control and PEM mice to stimulate HBsAg-specific memory lymphocytes. Values are means ± SEM, n = 3. *Different from control mice, P < 0.05.

    Levels of IL-12p70 and IFN- in cultures containing DC. The levels of IL-12p70 (154 ± 24 ng/L and 1324 ± 245 ng/L, respectively) and IFN- (53 ± 12 ng/L and 267 ± 16 ng/L, respectively) were lower in cultures containing DC from PEM mice compared with those in culture supernatants containing DC from control mice (P < 0.05).

	Discussion

TOP ABSTRACT Introduction Materials and Methods Results Discussion LITERATURE CITED

 
Chronic nutritional deficiencies are important causes of impaired immunocompetence and can be causal factors in increased susceptibility to infectious diseases in both relatively healthy people and hospitalized patients (1,3). Undernourished persons also respond poorly to prophylactic vaccines (4–8). However, it is difficult to assess the direct impact of undernutrition on immune responses, because most patients with undernutrition also suffer from other pathological lesions that may affect host immunity in addition to nutritional factors. Undernourished patients on hemodialysis respond poorly to HB vaccine, but they obviously also suffer from concurrent kidney disease (4,5). Increased morbidity and mortality have been reported in undernourished older persons due to infection with influenza virus (8); however, the advanced age of these patients may also play an important role in the diminished immune responses.

Thus, the mechanism involved in the effects of nutrition on the immune system may be better addressed in experimental systems in which the influence of diet and nutrients can be more precisely controlled. Along these lines, investigators have prepared murine models of dietary restriction and have found an association between dietary restriction and reduced body weight gain, thymus atrophy, and reduced numbers of lymphocytes (9–13). Diminished proliferation of lymphocytes in diet-restricted subjects has been reported, although there are also reports in the literature of no effect in such subjects (14–16).

To study the effects of chronic undernutrition on immune responses, we prepared PEM mice by restricting male C57BL/6 mice to a daily food intake equivalent to 70% of the amount consumed by control mice for 52 wk (Figs. 1 and 2; Table 1). In comparison to control mice, HBsAg-specific immune responses were significantly decreased in PEM mice. Anti-HBs were not detected in the sera in 8 of 10 PEM mice and very low levels of anti-HBs were found in only 2 of 10 PEM mice due to immunization with hepatitis B vaccine containing HBsAg. This outcome contrasted with very high levels of anti-HBs in the sera of all control mice. The magnitude of HBsAg-specific cellular immune responses was significantly lower in PEM mice compared with control mice.

In this study, lymphocytes from control mice and PEM mice showed similar levels of proliferation in response to stimulation with polyclonal mitogens. However, there is lack of consensus about this in the literature. In fact, many questions regarding the effects of dietary restriction on cell proliferation have not been properly addressed. In particular, details of the response of cell proliferation to dietary restriction, including the time course, dose-response relation, and endocrine correlations, have not been established (13). Moreover, the effect of using different control groups in the dietary restriction field also has not been systematically explored. However, the results of this study are supported by those of Conzen et al. (16), who found that T cell proliferation was not altered in chronically protein-deprived mice. Nevertheless, although the proliferation of lymphocytes (on a per-cell basis) was not reduced in PEM mice in this study, the total numbers of lymphocytes were only 25% of those of control mice; thus, a role for lymphocytes in the impaired HBsAg-specific immune responses in these mice cannot be completely dismissed.

In this context, the role of DC was evident for impaired HBsAg-specific immune responses in PEM mice. The numbers of spleen DC were significantly lower in PEM mice compared with control mice (Table 2). In addition, DC from PEM mice were less potent in processing HBsAg in vitro (as evidenced by the impaired stimulation of HBsAg-specific memory lymphocytes by HBsAg-pulsed DC of PEM mice). DC of PEM mice also had significantly diminished abilities to activate HBsAg-specific lymphocytes (Fig. 3). In addition, DC from PEM mice produced lower levels of IL-12p70 and IFN- compared with those produced by control mice. Because DC recognize and capture antigens in situ, process them in their endosomal compartments, and induce antigen-specific immune responses in situ (17–19), decreased antigen processing and presentation capacities of DC of PEM mice can explain why lower levels of anti-HBs and HBsAg-specific immune responses were induced in PEM mice. We and others have reported a relation between impaired DC function and pathogenesis of various diseases such as cancers, chronic viral infections, and autoimmune diseases (27,28). In addition, DC-based therapy has successfully been applied in various pathological conditions in mice and humans (18,19). In the context of nutritional immunity, Shi et al. (11) have documented defective antigen presentation in energy-restricted, gastrointestinal nematode-infected mice.

In this study, we intentionally assessed the efficacy of hepatitis B vaccine in chronically undernourished mice. Infection with hepatitis B virus is related to progressive liver diseases, such as liver cirrhosis and liver cancer. About 400 million people are chronically infected with this virus, and >90% of them live in the developing nations of the world (29). The WHO recommended adding the hepatitis B vaccination to all immunization programs for preventing further spread of the virus (30). We showed that the efficacy of the hepatitis B vaccine depends on the host nutritional status and the efficacy of the present regimen of hepatitis B vaccine should be evaluated in subjects afflicted with chronic nutritional deficiencies. However, there are some limitations in translating the findings of this study from the laboratory to clinical practice. In this study, PEM mice received reduced amounts of food for 52 wk, about one-half of the life span of mice. The efficacy of the hepatitis B vaccine should be evaluated in chronically undernourished subjects to determine whether there is a need to revisit the present regimen of global hepatitis B vaccination.

Moreover, the influence of feeding behavior on HBsAg-specific immune responses was not addressed in this study. PEM mice ate food comparatively more quickly than control mice, because they were given 30% less food each day. Future studies should evaluate the effect of feeding behavior on immune responses.

Understanding the biochemical and molecular targets of immune responses in PEM may lead to new prophylactic and therapeutic strategies to counter the impaired responses to vaccine and other adverse effects of malnutrition in hospitalized patients. The optimal approach would be to improve the nutritional status of the hosts, but this solution may not be possible in many cases because of complicating underlying diseases. The true benefit of these studies may be in identifying immune-associated biomarkers, which can be used in dietary supplementation and pharmacologic studies to prevent or treat various pathological conditions. Studies have shown that dietary supplements also regulate different parameters of immunity (31,32); however, little is known about the impact of these supplements on DC, the regulator of antigen-specific immune responses. Further study is required to address this question and to analyze the functional capacities of DC in people with undernutrition and malnutrition.

	FOOTNOTES

 
¹ Supported by the Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology, Japan to Sk. Md. Fazle Akbar and Morikazu Onji.

² Abbreviations used: anti-HBs, antibody to HBsAg; DC, dendritic cell; HBsAg, Hepatitis B surface antigen; PEM, protein energy malnutrition.

Manuscript received 13 September 2006. Initial review completed 31 October 2006. Revision accepted 13 December 2006.

	LITERATURE CITED

TOP ABSTRACT Introduction Materials and Methods Results Discussion LITERATURE CITED

 

1. Ritz BW, Gardner EM. Malnutrition and energy restriction differentially affect viral immunity. J Nutr. 2006;136:1141–4.[Abstract/Free Full Text]

2. McMurray DN, Bartow RA. Immunosuppression and alteration of resistance to pulmonary tuberculosis in guinea pigs by protein undernutrition. J Nutr. 1992;122 Suppl:738–43.[Abstract/Free Full Text]

3. Redmond HP, Shou J, Kelly CJ, Schreiber S, Miller E, Leon P, Daly JM. Immunosuppressive mechanisms in protein-calorie malnutrition. Surgery. 1991;110:311–7.[Medline]

4. Fernandez E, Betriu MA, Gomez R, Montoliu J. Response to the hepatitis B virus vaccine in haemodialysis patients: influence of malnutrition and its importance as a risk factor for morbidity and mortality. Nephrol Dial Transplant. 1996;11:1559–63.[Abstract/Free Full Text]

5. Dacko C, Holley JL. The influence of nutritional status, dialysis adequacy, and residual renal function on the response to hepatitis B vaccination in peritoneal dialysis patients. Adv Perit Dial. 1996;12:315–7.[Medline]

6. el-Gamal Y, Aly RH, Hossny E, Afify E, el-Taliawy D. Response of Egyptian infants with protein calorie malnutrition to hepatitis B vaccination. J Trop Pediatr. 1996;42:144–5.

7. Gardner EM. Caloric restriction decreases survival of aged mice in response to primary influenza infection. J Gerontol A Biol Sci Med Sci. 2005;60:688–94.[Abstract/Free Full Text]

8. Wouters-Wesseling W, Rozendaal M, Snijder M, Graus Y, Rimmelzwaan G, De Groot L, Bindels J. Effect of a complete nutritional supplement on antibody response to influenza vaccine in elderly people. J Gerontol A Biol Sci Med Sci. 2002;57:M563–6.[Abstract/Free Full Text]

9. Ing R, Su Z, Scott ME, Koski KG. Suppressed T helper 2 immunity and prolonged survival of a nematode parasite in protein-malnourished mice. Proc Natl Acad Sci USA. 2000;97:7078–83.[Abstract/Free Full Text]

10. Lotfy OA, Saleh WA, el-Barbari M. A study of some changes of cell-mediated immunity in protein energy malnutrition. J Egypt Soc Parasitol. 1998;28:413–28.[Medline]

11. Shi HN, Scott ME, Stevenson MM, Koski KG. Energy restriction and zinc deficiency impair the functions of murine T cells and antigen-presenting cells during gastrointestinal nematode infection. J Nutr. 1998;128:20–7.[Abstract/Free Full Text]

12. Redmond HP, Leon P, Lieberman MD, Hofmann K, Shou J, Reynolds JV, Goldfine J, Johnston RB Jr, Daly JM. Impaired macrophage function in severe protein-energy malnutrition. Arch Surg. 1991;126:192–6.[Abstract/Free Full Text]

13. Hsieh EA, Chai CM, Hellerstein MK. Effects of caloric restriction on cell proliferation in several tissues in mice: role of intermittent feeding. Am J Physiol Endocrinol Metab. 2005;288:E965–72.[Abstract/Free Full Text]

14. Riley-Roberts ML, Turner RJ, Evans PM, Merry BJ. Lymphoproliferative responses in diet-restricted and aging Sprague-Dawley rats. Exp Gerontol. 1992;27:201–9.[Medline]

15. Kubo C, Johnson BC, Day NK, Good RA. Effects of calorie restriction on immunologic functions and development of autoimmune disease in NZB mice. Proc Soc Exp Biol Med. 1992;201:192–9.[Medline]

16. Conzen SD, Janeway CA. Defective antigen presentation in chronically protein-deprived mice. Immunology. 1988;63:683–9.[Medline]

17. Reis e Sousa C. Dendritic cells in a mature age. Nat Rev Immunol. 2006;6:476–83.[Medline]

18. Akbar SMF, Furukawa S, Horiike N, Onji M. Vaccine therapy for hepatitis B virus carrier. Curr Drug Targets Infect Disord. 2004;4:93–101.[Medline]

19. Steinman RM, Pope M. Exploiting dendritic cells to improve vaccine efficacy. J Clin Invest. 2002;109:1519–26.[Medline]

20. Akbar SMF, Abe M, Masumoto T, Horiike N, Onji M. Mechanism of action of vaccine therapy in murine hepatitis B virus carriers: vaccine-induced activation of antigen presenting dendritic cells. J Hepatol. 1999;30:755–64.[Medline]

21. Furukawa S, Akbar SMF, Hasebe A, Horiike N, Onji M. Production of hepatitis B surface antigen-pulsed dendritic cells from immunosuppressed murine hepatitis B virus carrier: evaluation of immunogenicity of antigen-pulsed dendritic cells in vivo. Immunobiology. 2004;209:551–7.[Medline]

22. Akbar SMF, Onji M, Inaba K, Yamamura K-I, Ohta Y. Low responsiveness of hepatitis B virus transgenic mice in antibody response to T-cell-dependent antigen: defect in antigen presenting activity of dendritic cells. Immunology. 1993;78:468–73.[Medline]

23. Akbar SMF, Inaba K, Onji M. Upregulation of MHC class II antigen on dendritic cells from hepatitis B virus transgenic mice by g-interferon: abrogation of immune response defect to a T-cell-dependent antigen. Immunology. 1996;87:519–27.[Medline]

24. Hasebe A, Akbar SMF, Furukawa S, Horiike N, Onji M. Impaired functional capacities of liver dendritic cells from murine hepatitis B virus (HBV) carriers: relevance to low HBV-specific immune responses. Clin Exp Immunol. 2005;139:35–42.[Medline]

25. Akbar SMF, Horiike N, Onji M. Prognostic importance of antigen presenting dendritic cells during vaccine therapy in murine hepatitis B virus carriers. Immunology. 1999;96:98–108.[Medline]

26. Akbar SMF, Furukawa S, Hasebe A, Horiike N, Michitaka K, Onji M. Production and efficacy of a dendritic cell-based therapeutic vaccine for murine chronic hepatitis B virus carrier. Int J Mol Med. 2004;14:295–9.[Medline]

27. Fazle Akbar SM, Abe M, Yoshida O, Murakami H, Onji M. Dendritic cell-based therapy as multidisciplinary approaches against cancer treatment: present limitations and future scopes. Curr Med Chem. 2006;13:3113–9.[Medline]

28. Figdor CG, de Vries IJ, Lesterhuis WJ, Melief CJ. Dendritic cell immunotherapy: mapping the way. Nat Med. 2004;10:475–80.[Medline]

29. Alter MJ. Epidemiology and prevention of hepatitis B. Semin Liver Dis. 2003;25:39–46.

30. WHO. Hepatitis B. World Health Fact Sheet 204 [monograph on the Internet] Geneva: WHO; 2000 [updated 2000; cited October 2004]. Available from: http://who.int/inf-fs/en/fact204.html.

31. Chandra RK. Impact of nutritional status and nutrient supplements on immune responses and incidence of infection in older individuals. Ageing Res Rev. 2004;3:91–104.[Medline]

32. Nakamura I, Ochiai K, Imawari M. Phagocytic function of neutrophils of patients with decompensated liver cirrhosis is restored by oral supplementation of branched-chain amino acids. Hepatol Res. 2004;29:207–11.[Medline]

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