Exercise and psychosocial factors modulate immunity to influenza vaccine in elderly individuals

Mood and cytokine response to influenza virus in older adults

BACKGROUND

Previous research has indicated that older adults with severe life stress show attenuated immune responses to influenza vaccination. Associations among mood, optimism, stress, and the in vitro cytokine response to influenza virus and vaccine were evaluated in 18 healthy older adults with low to moderate life stress.

METHODS

Peripheral blood mononuclear cells were stimulated in cultures with 1999-2000 influenza vaccine viruses (A/Beijing/262/95, A/Sydney/5/97, and B/Yamanashi/166/98) and the 2000-2001 trivalent vaccine (containing A/New Caledonia/20/99, A/Panama/2007/99, and B/Yamanashi/166/98). The levels of T-helper type 1 (interleukin-2 and interferon-gamma) and type 2 (interleukin-10) cytokines were measured in culture supernatants.

RESULTS

Stress, age, and current health practices were unrelated to cytokine production. Older adults reporting greater anger, fatigue, confusion, and total mood disturbance had poorer cytokine responses to live virus and vaccine stimulation. In contrast, older adults who reported greater vigor and those who were more optimistic had greater cytokine responses to both live virus and vaccine. These relationships were largely unaffected by medications or health conditions.

CONCLUSIONS

These findings suggest that among older adults, even mild to moderate mood disturbance is associated with an attenuated cellular immune response to live influenza virus and vaccine.

Moderate exercise improves antibody response to influenza immunization in older adults

Influenza vaccine efficacy is reduced among adults over age 65 and a significant number of vaccinated elderly may remain susceptible to influenza virus infection. The effect of moderate exercise training on the immune response to influenza immunization was evaluated in this study. Twenty-seven adults >or=age 64 were assigned to an exercise group (n= 14) or a control group (n = 13). The subjects exercised at 65-75% heart rate reserve (HRR), 25-30 min, 3 days per week, for 10 months. Controls did not change activity. Subjects were immunized with trivalent influenza vaccine before and after the exercise intervention. After the exercise intervention, exercisers exhibited a greater mean fold increase (MFI) in antibody titer to influenza A/New Caledonia/20/99 (H1N1) and A/Panama/2007/99 (H3N2) than controls, and a greater Granzyme B activity to A/Panama/2007/99 than controls. These findings suggest that exercise may enhance the mean fold increase in antibody titer in response to influenza immunization if the influenza antigen was contained in the previous year's vaccine.

Influence of age and physical activity on the primary in vivo antibody and T cell-mediated responses in men

The aging immune system is characterized by the progressive decline in the antibody and T cell-mediated responses to antigen. Little is known, however, about the benefits of exercise in aging on the generation of a primary immune response to antigen and the subsequent antibody and memory T cell-mediated response. Most in vivo immune research to date has utilized vaccines or recall antigens to elicit an immune response. Therefore, the purpose of this experiment was to examine the association of aging and physical activity on the primary antibody and T cell response to the novel protein antigen keyhole-limpet hemocyanin (KLH). Forty-six physically active and sedentary, young (20-35 yr) and older (60-79 yr) men were recruited. Subjects were intramuscularly immunized with 100 microg of KLH, and blood samples were collected at days 0, 7, 14, 21, and 28. Samples were measured for anti-KLH IgM, IgG, IgG1, and IgG2 by ELISA. On day 21 after intramuscular KLH administration, subjects received an intradermal injection with 1 microg of KLH of inflammation recorded at 24, 48, 72, 96, and 120 h to assess anti-KLH delayed-type hypersensitivity response. There was a significant reduction in all anti-KLH measures with aging except for anti-KLH IgG2. The physically active older group had significantly higher anti-KLH IgM, IgG, IgG1, and delayed-type hypersensitivity responses, but not IgG2 compared with the sedentary older group. In conclusion, regular physical activity in older men is associated with a more robust immune response to novel antigenic challenge.

Exercise immunology: the current state of man and mouse

The mechanisms governing the body's response to physical exercise have been investigated from various perspectives including metabolism, nutrition, age and sex. Increased attention to the immune system during recent decades is reflected by a rapidly growing number of publications in the field. This article highlights the most recent findings and only briefly summarises more basic concepts already reviewed by others. Topics include Th1/Th2 cytokine balance, inoculation time, age and immune compensation. Some less investigated areas are discussed including studies in children, the environment and dendritic cells. Because physical exercise enhances some aspects and suppresses other aspects of immunity, the biological significance of alterations in the immune system are unknown. So far, no link between immunological alterations and infection rate has been established and infection after strenuous physical exercise is equally likely to be the result of exercising with an already established rather than a new infection. If there is an increased risk for infections with increased exercise duration and intensity, why do overtrained athletes not display the greatest risk for upper respiratory tract infections? Increased knowledge on immune system modulations with physical exercise is relevant both from a public health and elite athlete's point of view.

The effect of exercise training on the kinetics of the antibody response to influenza vaccination

The significance of in vitro changes in immune function accompanying exercise training is unclear. To determine the effect of exercise on the response of the intact immune system to a challenge in vivo, we measured the speed and overall immunoglobulin G (IgG) response to influenza vaccination in humans engaged in different intensities of activity. Male participants (n = 21) were split into heavy and light training groups. Venous blood samples were collected 0, 2, 4, 7, 10 and 14 days after vaccination with trivalent influenza vaccine, and also 12 months after initial vaccination. Serum IgG was determined by enzyme-linked immunosorbant assay. There was a significant difference in baseline IgG between groups, but no difference in IgG concentration 14 days after vaccination. The IgG concentration remained elevated 12 months post-vaccination in the heavy training group. The results suggest a positive relationship between habitual physical activity and baseline antibody concentrations, which, in turn, affects the relative magnitude (fold or percentage increase) of the antibody response to vaccination. The training loads of the participants in this study had no effect on overall IgG measured 14 days after vaccination.

Exercise training-induced adaptations of immune response are mediated by β-adrenergic receptors in aged but not young mice

β-Adrenergic blockade was used to determine whether the exercise training-induced adaptations of immune response to viral infection were mediated by catecholamines in young and old mice. Young (2 mo) and older (16 mo) male BALB/c mice were randomly assigned to an exercise or control group, and half of the mice in each group received the β-adrenergic receptor antagonist nadolol. After 8 wk of moderate exercise training, mice were challenged with herpes simplex virus (HSV) 24 h postexercise. The results showed that exercise treatment increased anti-HSV IgM antibody, enhanced IL-10, and altered the kinetics of IFN-γ and IL-2 production in young and old mice. Unique to older mice, exercise decreased mitogen-induced proliferation, increased splenocytes, and tended to decrease memory cells (CD44hi+). In contrast, exercise increased mitogen-induced proliferation but decreased the number of splenic lymphocyte and CD4+ cells in young mice. β-Adrenergic blockade blunted the exercise-induced changes in anti-HSV IgM, IL-2, IFNγ, and mitogen-induced proliferation in old but not young mice. The findings suggest that some of the immunomodulatory effects of chronic exercise are mediated via β-adrenergic receptors and that the role of β-adrenergic receptors is age dependent.

Psychological stress and antibody response to influenza vaccination: when is the critical period for stress, and how does it get inside the body?

OBJECTIVES

This study attempted to determine whether stress of moderate intensity could modulate the antibody response to an influenza vaccination in healthy young adults, identify critical periods during which stress could influence antibody response, and delineate behavioral and biological pathways that might explain relations between stress and antibody.

METHODS

A cohort of 83 healthy young adults underwent 13 days of ambulatory monitoring before, during, and after vaccination. Four times daily, subjects reported the extent to which they felt stressed and overwhelmed and collected a saliva sample that was later used to measure cortisol. A battery of health practices (cigarette smoking, alcohol use, physical activity, sleep hygiene) was assessed daily. Antibody titers to the vaccine components were measured at baseline and at 1-month and 4-month follow-up assessments.

RESULTS AND CONCLUSIONS

To the extent that they reported higher levels of stress across the monitoring period, subjects exhibited poorer antibody responses to the New Caledonia strain of the vaccine. Stress ratings on the 2 days before the vaccine and the day it was given were not associated with antibody response. However, the 10 days afterward appeared to be a window of opportunity during which stress could shape the long-term antibody response to varying degrees. With respect to potential mediating pathways, little evidence emerged in favor of cortisol secretion, alcohol consumption, physical activity, or cigarette smoking. However, analyses were consistent with a pattern in which feelings of stress and loss of sleep become locked into a feed-forward circuit that ultimately diminishes the humoral immune response. These findings may shed light on the mechanisms through which stress increase vulnerability to infectious disease.

Mortality and readmission of the elderly one year after hospitalization for pneumonia

BACKGROUND AND AIMS

Pneumonia, which is common among the elderly, is associated with untoward consequences. We sought, therefore, to describe the incidence of death and readmission, and to determine predictors of these variables during the year subsequent to index hospitalization.

METHODS

This study involved the follow-up of 153 patients surviving an index hospitalization for pneumonia. Death and readmission were documented, and the relationship of selected variables with these outcomes was determined.

RESULTS

Ninety-six (62.6%) of the patients had died or were readmitted. Only a count of comorbidities was correlated significantly with death, readmission, and either death or readmission. Using regression analysis, death alone was predicted by multiple variables. Grip strength and comorbidity counts correctly classified 75.2% of patients relative to that outcome.

CONCLUSIONS

Untoward outcomes are likely among patients surviving acute hospitalization for pneumonia. These outcomes are related to variables that can be targeted in secondary prevention efforts.

Psychoneuroimmunology and health psychology: an integrative model

The biopsychosocial model describes interactions between psychosocial and biological factors in the etiology and progression of disease. How an individual interprets and responds to the environment determines responses to stress, influences health behaviors, contributes to the neuroendocrine and immune response, and may ultimately affect health outcomes. Health psychology interventions are designed to modulate the stress response and improve health behaviors by teaching individuals more adaptive methods of interpreting life challenges and more effective coping responses. These interactions are discussed in the context of aging.