Motivational syndromes associated with natural killer cell activity

The implicit affiliation motive moderates cortisol responses to acute psychosocial stress in high school students

It has been previously shown that the implicit affiliation motive - the need to establish and maintain friendly relationships with others - leads to chronic health benefits. The underlying assumption for the present research was that the implicit affiliation motive also moderates the salivary cortisol response to acute psychological stress when some aspects of social evaluation and uncontrollability are involved. By contrast we did not expect similar effects in response to exercise as a physical stressor. Fifty-nine high school students aged M=14.8 years were randomly assigned to a psychosocial stress (publishing the results of an intelligence test performed), a physical stress (exercise intensity of 65-75% of HRmax), and a control condition (normal school lesson) each lasting 15min. Participants' affiliation motives were assessed using the Operant Motive Test and salivary cortisol samples were taken pre and post stressor. We found that the strength of the affiliation motive negatively predicted cortisol reactions to acute psychosocial but not to physical stress when compared to a control group. The results suggest that the affiliation motive buffers the effect of acute psychosocial stress on the HPA axis.

The modulation of immunological activities in human NK cells by extracts of ginkgo

OBJECTIVE

To investigate the association between extracts of ginkgo and the immune system by determining changes in natural killer (NK) cell activity and surface markers in human NK cells and by analyzing for surface markers.

METHODS

Natural killer cell activity was determined in peripheral blood samples of three subjects who received ginkgo daily (250 ml/day; (ginkgo concentration 40 mg/ml) for 14 days by the non-radioisotopic Europium (non-RI Eu) release assay. Peripheral blood samples were taken three times during the study period: before ginkgo sample ingestion, on day 7 after ginkgo ingestion, and on day 14 after ginkgo ingestion). The peripheral blood samples were also analyzed for surface markers (CD56, CD3, CD19, CD20, CD4, CD8) using a fluorescence-activated cell sorter (FACScalibur).

RESULTS

The non-RI Eu release assay revealed that the ingestion of ginkgo extracts elevated NK cell activity in the subjects, with the highest activity recorded following treatment with an extract at a concentration of 400-800 μg/ml. The analysis for surface markers using the FACScalibur showed that the expression of CD56 (NK cell surface marker) was elevated and the expression of CD19 had dropped in our subjects by day 14 of ginkgo ingestion. There was no significant difference in surface markers after 7 days of ginkgo ingestion.

CONCLUSION

Ginkgo extracts were found to affect immunological activities and surface markers (CD56) in human NK cells. Our results also reveal an optimal range of ginkgo concentration-from 400 to 800 μg/ml-within which its immunopotentiating activity is highest. It took at least 2 weeks to affect surface markers in human NK cells after ginkgo ingestion, and surface markers were not affected after 7 days of ginkgo ingestion.

Assessment of implicit motives with a research version of the TAT: picture profiles, gender differences, and relations to other personality measures

Four hundred twenty-eight participants wrote imaginative stories in response to 6 picture cues of a research version of the Thematic Apperception Test (TAT; Morgan & Murray, 1935). Story protocols were coded for n (need) Power, n Achievement, and n Affiliation using Winter's (1991) integrated scoring system that provided detailed information about the motive profiles of individual picture cues. In general, picture cues differed strongly from each other with regard to how many scorable instances of power, achievement, or affiliation imagery they elicited. The n Affiliation, but not n Power, n Achievement, or activity inhibition--a measure of impulse control--was found to be higher in (a) women than in men and (b) individuals tested in a group than in individuals tested individually. TAT motive measures showed no significant overlap with questionnaire measures of motivational orientation (German Personality Research Form; Stumpf, Angleitner, Wieck, Jackson, & Beloch-Till, 1985) or traits (German NEO-Five-Factor Inventory; Borkenau & Ostendorf, 1993).

Personality and the immune system: models, methods, and mechanisms

A relationship between personality and the immune system has been hypothesized for at least 25 years, and understanding this relationship could contribute to understanding how personality affects the onset and course of chronic diseases such as cancer and heart disease. A number of personality dimensions, including repression, optimism, hostility, attributional style, and extraversion-introversion, have been related to immune parameters or immunity. Theoretical and methodological issues in interpreting the extant literature and in planning future research include selection of personality dimensions to study, study design, and attention to potential psychosocial mediators. Past and future investigations using sophisticated theory and methodology to investigate the ongoing influence of personality on physiological systems, including the immune system, promise to advance the understanding of both.

Natural killer (NK) cell activity and NK cell subsets in workers with a tendency of burnout

The involvement of cellular immunity in the burnout syndrome remains to be elucidated. We assessed three components of burnout of the Maslach Burnout Inventory: emotional exhaustion; depersonalization (DP); and personal accomplishment, as well as natural killer cell activity (NKCA) and NK cell subsets in 42 male workers. Workers with a higher DP score showed a lower NKCA and a lower proportionality of CD57+CD16+ to total lymphocytes. There were no differences in any of the health behaviors (e.g., smoking, alcohol, or obesity) between workers showing higher burnout and those showing lower burnout. A stepwise multiple regressions analysis demonstrated that NKCA was closely correlated with DP, independent of other variables, including a stress index. These results suggest that the relationship between reduced cellular immunity and DP is not due to traditional work stress or health behavioral problems. Further studies on DP as a psychosomatic disorder as well as an occupational health problem should be performed in the future.

Stress, depression and immunity: the role of defense and coping styles

It is by now widely recognized that acute and chronic stress have an impact on the immune system. Acute stress may have a stimulating effect on the immune system, while in the case of chronic stress--and in particular in depression--the immune system may be down-regulated. However, there is considerable individual variability in the immune response to stress. This seems to a large extent to be determined by the subject's way of dealing with stress. The perception and evaluation of a stressor and the specific ways of stress coping may in different ways be related to various aspects of the stress response: sympathetic nervous system (SNS) activation and activation of the hypothalamic-pituitary-adrenal (HPA) axis, both systems affecting the immune system. Prolonged exposure to stressors or to severe life stresses may outweigh the person's coping resources leading to feelings of depression. The affective changes with the accompanying changes in the HPA axis are one of the hypothesized mechanisms underlying the immune changes in depression. It should be noted that the relationship between depression and immunity is affected by several other factors, such as gender and age and other personal resources. Increasing the subject's abilities to cope with stress and to reduce the negative affect by psychological interventions may on the other hand have a beneficial effect on the immune system.

Psychosocial vulnerability to stress: a study of HIV-positive homosexual men

Sixty-one homosexual men with HIV infection participated in a 12-month investigation into the role of stressful life events and mediating variables in the stress process. The results revealed that frequency of stressful life events and psychosocial resilience (a factor indexing levels of support, worry, personal self-esteem, and effective coping efforts) significantly predicted levels of emotional distress in this sample. The combined influence of these variables accounted for 53% (Phase 2) and 55% (Phase 3) of the variance in levels of emotional distress. The data point to a need to incorporate measures of life event frequency and several, rather than single, mediating variables in studies investigating the stress process.

Health psychology: psychological factors and physical disease from the perspective of human psychoneuroimmunology

This review addresses the importance of studies of human psychoneuroimmunology in understanding the role of psychological factors in physical illness. First, it provides psychologically and biologically plausible explanations for how psychological factors might influence immunity and immune system-mediated disease. Second, it covers substantial evidence that factors such as stress, negative affect, clinical depression, social support, and repression/denial can influence both cellular and humoral indicators of immune status and function. Third, at least in the case of the less serious infectious diseases (colds, influenza, herpes), it considers consistent and convincing evidence of links between stress and negative affect and disease onset and progression. Although still early in its development, research also suggests a role of psychological factors in autoimmune diseases. Evidence for effects of stress, depression, and repression/denial on onset and progression of AIDs and cancer is less consistent and inconclusive, possibly owing to methodological limitations inherent in studying these complex illnesses, or because psychological influences on immunity are not of the magnitude or type necessary to alter the body's response in these cases. What is missing in this literature, however, is strong evidence that the associations between psychological factors and disease that do exist are attributable to immune changes.

Modulatory effects of defense and coping on stress-induced changes in endocrine and immune parameters

We examined whether habitual defense and coping affect the response of hormones (ACTH. cortisol, prolactin. endorphins, and noradrenaline) and immune parameters (numbers of T cells. B cells. natural killer [NK] cells, and proliferative responses to mitogens or antigens) to an acute laboratory stressor (i.e., solving a 3-dimensional puzzle and explaining it to a confederate) in 86 male high school teachers. Defense and coping were assessed by Kragh's tachistoscopic Defense Mechanism Test (a measure of perceptual defense) and by 4 questionnaire-based coping styles assessing instrumental mastery-oriented coping, emotion-focused coping, cognitive defense, and defensive hostility. The laboratory stressor per se caused a relative increase in immunological (in particular NK cells) and endocrine (cortisol, prolactin) parameters. Defense and coping, however, significantly codetermined the response to the stressor. In particular, instrumental mastery-oriented coping and perceptual defense were related to stress-induced changes in numbers of B cells and in the pituitary-adrenal hormones. The results indicate that the impact of a mild psychological stressor on the immune and endocrine system depends to a considerable extent on the specific ways people deal with stressors.

Psychobiological factors related to human natural killer cell activity and hormonal modulation of NK cells in vitro

The present report investigated whether percentages of circulating natural killer (NK) cells and NK cell activity (NKCA) are associated with psychological variables. Subjects (n = 95) were selected, based on a combination of low or high scores on questionnaires on daily hassles and self-reported symptoms, to create four extreme groups. NK cell percentages were different between two of the four groups, only when the analysis was not controlled for gender, life style and endocrine parameters. No evidence was found for a relationship between group membership and NKCA. NKCA, however, was found to differ between men and women and to be associated with percentages of NK cells and intracellular levels of cAMP. Furthermore, the hypothesis was tested, that hormone-induced changes in NKCA in vitro are dependent on the individual's current stress profile. To investigate this issue, NKCA was measured after cells had been incubated with hydrocortisone (10(-6) or 10(-7) M) or the beta-adrenergic agonist isoprenaline (10(-5) or 10(-7) M) in vitro. Changes in NKCA were found to be related to plasma adrenaline levels, but no evidence was found for involvement of psychological variables. It is concluded that, in the current setting, there is no association between the combination of scores on the two psychological questionnaires, and NKCA or hormone-induced changes therein.

The effect of stress and psychosocial variables on natural killer cells: a review

In this review we discuss the results of studies about the effect of stress, depression, anxiety, social support and various psychosocial treatments on numbers and activity of Natural Killer (NK) cells. In general a suppressive effect is observed among depressive persons and persons who react to stressfull events with feelings of helplessness and anxiety. Lack of social support also seems to engender immunosuppression including NK suppression. Various forms of psychosocial care seem to be able to undo these negative consequences. However, the real clinical relevance of these findings is still a matter of dispute.

Personality and health: advantages and limitations of the five-factor model

Interest in the association between personality characteristics and physical health has been renewed in recent years. Theory and research in this area has also been complicated by conceptual and methodological limitations. The present article briefly reviews this literature and discusses the advantages and limitations of the five-factor model of personality as an integrating framework for studies of personality and health. The model has already been fruitfully applied in several contexts, and more possibilities exist. Although it has some potential limitations, the application of the five-factor model--as well as other aspects of current personality theory and research--is likely to facilitate progress in the study of how personality influences health.