Robert H. Bonneau

Stress-Induced Modulation of the Immune Response to Recombinant Hepatitis B Vaccine

&NA; Each of a series of three hepatitis B (Hep B) inoculations was given to 48 second‐year medical students on the 3rd day of a 3‐day examination series to study the effect of academic stress on the ability to generate an immune response to a primary antigen. Those students who seroconverted after the first injection (25%) were significantly less stressed and anxious than those who did not seroconvert at that time. In addition, students who reported greater social support demonstrated a stronger immune response to the vaccine at the time of the third inoculation, as measured by antibody titers to Hep B surface antigen (HBsAg) and the blastogenic response to a HBsAg peptide (SAg).

Restraint stress differentially affects anti-viral cellular and humoral immune responses in mice

Physical restraint administered to C57BL/6 mice significantly altered the inflammatory response to influenza virus infection and depressed anti-viral cellular immunity. Restraint-stressed animals showed a pattern of reduced mononuclear cell infiltration and lung consolidation which coincided with elevated plasma corticosterone levels. Furthermore, cellular immunity to virus was significantly depressed; interleukin-2 secretion was reduced by 96% and 59% in the mediastinal lymph nodes and spleens, respectively, as compared to a non-restrained group. However, the magnitude of the humoral immune response to influenza virus was unaffected by restraint stress. Anti-viral IgG antibody levels in restrained/infected mice did not differ when compared to a non-restrained/infected control group 14 days post-infection.

Stress and the memory T-cell response to the Epstein-Barr virus in healthy medical students.

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.

Stress-induced suppression of herpes simplex virus (HSV)-specific cytotoxic T lymphocyte and natural killer cell activity and enhancement of acute pathogenesis following local HSV infection

Stressful events suppress a broad spectrum of both humoral and cellular immunological responses. However, studies of the effects of stress on the development of specific antiviral immune responses have not been reported. We have utilized an established murine model of an acute, local footpad Herpes simplex virus type 1 (HSV-1) infection to study the effect of restraint stress on the generation of HSV-specific cytotoxic T lymphocytes (CTL) and natural killer (NK) cell activity. Lymphoproliferative responses in the popliteal lymph nodes following footpad infection as well as the generation of HSV-specific CTL and NK cell activity were depressed in restrained mice compared to infected, unrestrained controls. Frequency analyses of HSV-specific pre-CTL indicated that suppression of the CTL response occurred early in the sequence of events that precedes the generation of functionally lytic CTL and was not mediated by a diminished IL-2 response. Although restrained mice exhibited fewer lymphocytes in the popliteal lymph nodes, the subset distribution was the same as that in the unrestrained controls. Furthermore, stress-induced immunosuppression resulted in a higher titer of infectious HSV at the site of infection. Overall, these findings provide evidence that physiological changes associated with restraint stress can influence the immune response to a specific viral infection and alter the course of viral pathogenesis.

Stress-induced modulation of the primary cellular immune response to herpes simplex virus infection is mediated by both adrenal-dependent and independent mechanisms

A murine model of herpes simplex virus (HSV) infection was used to examine the role of the adrenal gland in restraint stress-induced suppression of viral immunity. Adrenal-dependent mechanisms were important for suppressing the generation of HSV-specific cytotoxic T lymphocytes (CTL) but not the associated diminished lymphadenopathy in response to local HSV infection. While exogenous corticosterone administration alone was unable to suppress lymphadenopathy and CTL generation in adrenalectomized mice, an adrenal-independent mechanism induced by restraint stress functioned in synergy with corticosterone to suppress lymphadenopathy and CTL development. These results suggest that both adrenal-dependent and independent mechanisms contribute to stress-induced modulation of HSV immunity.

Stress-induced effects on cell-mediated innate and adaptive memory components of the murine immune response to herpes simplex virus infection

Using a murine model, we have previously shown that restraint stress is able to suppress the development of herpes simplex virus (HSV)-specific cytotoxic T lymphocytes (CTL) and natural killer (NK) cell activity in the popliteal lymph nodes following local footpad infection. These studies of the primary cell-mediated immune response to HSV infection have been extended to examine the effects of a similar stressor on the development of HSV-specific memory CTL (CTLm) following local and systemic HSV infection. In addition, the effect of stress on HSV-specific CTLm localization and proliferation in the popliteal lymph node following reexposure to HSV was investigated. Lastly, the ability to stimulate HSV-specific CTLm to the lytic phenotype under conditions of restraint stress was examined. Restraint stress did not inhibit the generation of HSV-specific CTLm. However, restraint stress inhibited the ability to activate CTLm to the lytic phenotype. In HSV seropositive mice (primed prior to stress), restraint stress prevented the in vivo activation and/or migration of HSV-specific CTLm in the popliteal lymph nodes. These findings demonstrate that activation of HSV-specific immunological memory can be inhibited by physiological changes associated with stress. Such immune inhibition may provide a possible mechanism for the development of recrudescent herpetic disease.

The effect of restraint stress on the kinetics, magnitude, and isotype of the humoral immune response to influenza virus infection

The stress of physical restraint has been shown to modulate the cellular immune response during a viral infection. We have studied the effects of stress on the humoral immune response during infection by influenza virus. Restraint stress altered the kinetics of the antibody response; seroconversion in the IgG and IgA isotypes was delayed in virus-infected C57BL/6 mice subjected to repeated cycles of physical restraint. However, the magnitude and isotype of the mature antibody response were unaffected during the plateau phase; no significant differences were observed between restrained/infected and nonrestrained/infected mice. Thus, the time during infection at which the antibody response was measured was a significant variable in the study of stress-induced alterations of the hosts response to a replicating viral antigen. While restraint stress did not significantly affect the magnitude or class of the humoral response, it did alter the kinetics of response.

Stress-associated modulation of proto-oncogene expression in human peripheral blood leukocytes

Changes in the cellular immune response associated with psychological stress were studied by using an academic stress model with medical students. The authors examined the expression of 2 proto-oncogenes, c-myc and c-myb, in peripheral blood leukocytes (PBLs) obtained from medical students at the time of examinations and at a baseline period approximately 1 month prior to the examinations. The level of messenger ribonucleic acid (mRNA) expression of both protooncogenes was significantly lower in PBLs obtained during examinations than in those from the baseline period. In addition, a significant decrease in the level of mRNA to the glucocorticoid receptor and gamma interferon was also found in the same preparations. The decrease in mRNA content of c-myc, c-myb, the glucocorticoid receptor, and gamma interferon in PBLs obtained from subjects during examinations is consistent with data from previous studies using the same model that have demonstrated a down-regulation of T-lymphocyte activation and proliferation in response to mitogens.

Stress-induced modulation of the immune response

The suggestion of and the evidence for an integration of the immune system with the central nervous system (CNS) and with the endocrine system has many roots as a result of both human’” and animal studies.Gg The complex interactions among these three systems have been the subject of many recent studies in the rapidly developing field of “psychoneuroimmunology”lo or more appropriately “psychoneuroendocrinimmunology” to account for the endocrine system’s known contribution in immune function modulation. Recent experimental evidence has suggested that the CNS-endocrine-immune axis (neuroendocrine-immune axis) proceeds in the direction of the immune response in that the immune system receives signals from the nervous system; in addition, the communication is bidirectional, since the immune system is capable of providing information to the nervous system. This intercellular communication is mediated by products of the immune system including cytokines, growth factors, and neuropeptides made by lymphocytes themselves. Therefore, the distinctions that have been made amonglymphokines, growth factors, hormones, and neuropeptides with respect to the organ system in which they function are no longer appropriate. Both surgical and exercise stress can promote the release of numerous pituitary and adrenal hormones. Thus, it has been suggested that stress can significantly modulate immune function via the endocrine system. Conflicting results have been obtained as to which hormones are secreted in response to stress; however, it is generally agreed upon that these results may be a function of the duration of stress applied along with frequency of the hormone sampling. Studies of the relationship between neuroendocrine peptides and regulation of the immune function have focused on those neuropeptides derived from the polyprotein proopiomelanocortin (POMC), particularly adrenocorticotropic hormone (ACTH) and Fendorphin. Other hormones such as cortisol, growth hormone, prolactin, and the catecholam-