No abstract

Healthy Epstein-Barr virus (EBV) seropositive undergraduates (N = 57) completed a personality inventory, provided blood samples, and were randomly assigned to write or talk about stressful events, or to write about trivial events, during three weekly 20-min sessions, after which they provided a final blood sample. Individuals assigned to the verbal/stressful condition had significantly lower EBV antibody titers (suggesting better cellular immune control over the latent virus) after the intervention than those in the written/stressful group, who had significantly lower values than those in the written/trivial control group. Subjects assigned to the written/stressful condition expressed more negative emotional words than the verbal/stressful and control groups and more positive emotional words than the verbal/stressful group at each time point. The verbal/stressful group expressed more negative emotional words compared with the control group at baseline. Content analysis indicated that the verbal/stressful group achieved the greatest improvements in cognitive change, self-esteem, and adaptive coping strategies.

To address the long-term physiological consequences of chronic stressors, 14 continuing or current family caregivers of Alzheimer's disease (AD) patients, 17 former AD caregivers, and 31 control subjects were compared. Continuing and former caregivers did not differ on depressive symptomatology or perceived stress; both groups were significantly more depressed and stressed than controls. Furthermore, continuing and former caregivers did not differ in the response of NK cells in vitro to recombinant interferon-gamma and recombinant interleukin-2, and both groups had a significantly poorer response to these cytokines than controls. The physiological and psychological consequences of chronic stressors may persist well beyond the cessation of the actual stressor.

The objective of this study was to address the cellular and psychological mechanisms underlying previously observed changes in natural killer (NK) cell cytotoxicity associated with chronic stress. We compared 28 current and former spousal caregivers of patients with Alzheimer's disease (AD) and 29 control subjects. NK cells were enriched (E-NK) using a 4-step procedure that resulted in a cell preparation consisting of 88.2% NK cells. These cells were then incubated with either recombinant interferon-gamma (rIFN-gamma) or recombinant interleukin-2 (rIL-2) for 65 hours. Although an average of over 3 years had elapsed since the death of the patient with AD for the former caregivers, current and former caregivers did not differ in the E-NK cell responses to rIFN-gamma and rIL-2. However, the E-NK cell response for the combined caregiver group was significantly suppressed compared with controls, which is consistent with a previous report from our laboratory. Higher E-NK cell responses to each cytokine were associated with heightened levels of positive emotional and tangible social support, independent of levels of depression. Preliminary data suggest that defects of NK cell function in response to rIFN-gamma and rIL-2 as a consequence of caregiver stress may be independent of non-NK cells. Finally, our data are consistent with other studies regarding the role of social support in immune modulation.

This study investigated the memory T-cell proliferative response to several early and late Epstein-Barr virus (EBV) polypeptides. Blood samples were collected twice, 1 month before a 3-day block of examinations and again on the last day of the exam series. Ss were 25 healthy, EBV seropositive medical students. The proliferative response to 5 of the 6 EBV polypeptides significantly decreased during examinations. In addition, Ss high (above the median) in seeking support, as measured by the COPE, had lower proliferative responses to 3 EBV polypeptides (p17, p52/50, and p85), as well as higher levels of antibody to EBV virus capsid antigen. The data provide further evidence that psychological stress can modulate the cellular immune response to latent EBV.