Decreased herpes simplex viral immunity and enhanced pathogenesis following stressor administration in mice

Mild electric footshock stress was delivered during the dark portion of a 12:12 h light:dark cycle to C57BL/6 female mice that were infected with herpes simplex virus-type 1 (HSV). The studies were designed to correlate viral titer with both humoral and cell-mediated immune responses to HSV infection. Footshock was observed to result in decreased HSV-specific immunity. The numbers of leukocytes in spleens and draining popliteal lymph nodes of footshocked mice were depressed compared to both apparatus control and home cage control mice. A significant suppression of the HSV-specific cytotoxic T lymphocyte (CTL) response was observed in both the spleen and popliteal lymph nodes of footshocked mice. Serum IgM anti-HSV antibody titers were also depressed in footshocked mice. These changes were shown to be correlated with significantly increased viral titers in footshocked mice compared to control mice. These data demonstrate that administration of a relatively mild stressor is associated with depressed HSV-specific cellular and humoral immunity and is associated with increased pathogenicity.

Psychoneuroimmunology: Can psychological interventions modulate immunity?

There is ample evidence from human and animal studies demonstrating the downward modulation of immune function concomitant with a variety of stressors. As a consequence, the possible enhancement of immune function by behavioral strategies has generated considerable interest. Researchers have used a number of diverse strategies to modulate immune function, including relaxation, hypnosis, exercise, classical conditioning, self-disclosure, exposure to a phobic stressor to enhance perceived coping self-efficacy, and cognitive-behavioral interventions, and these interventions have generally produced positive changes. Although it is not yet clear to what extent these positive immunological changes translate into any concrete improvements in relevant aspects of health, that is, alterations in the incidence, severity, or duration of infectious or malignant disease, the preliminary evidence is promising.

Stress-induced modulation of the immune response to recombinant hepatitis B vaccine

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).

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 host's 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.

The influence of academic stress and season on 24-hour concentrations of growth hormone and prolactin

Stress has been considered a physiological regulator of GH and PRL secretion in humans. The stressors used in studies have often been extreme. The influence of commonplace stressors on the endocrine system has not been clarified. Therefore, to better define the role of commonplace stressors on GH and PRL secretion, we evaluated the effect of examination stress on GH and PRL secretion in 37 male medical students. We performed hourly sampling for 24 h for GH and PRL 4 weeks before, during exam week, and 2 weeks after major examinations in the fall and spring of their first year. Stress, as evaluated by the Perceived Stress Scale (PSS), increased as expected during examination weeks, but there was no correlation between the PSS scores and mean day or night GH and PRL secretion. Twenty-four-hour GH and PRL secretion was not significantly altered during examinations in either fall or spring. A significant seasonal influence, however, was noted on GH secretion, with both daytime and nocturnal GH secretion being consistently higher in the Fall than in the Spring. We conclude that examination stress does not significantly influence mean daytime or nocturnal GH and PRL concentrations. We suggest that serum GH and PRL levels may not be significantly altered in man by commonplace stressors. Also, seasonal effects may be operative in the control of human GH secretion.

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 influence of chlorpromazine on the potential-induced shape change of human erythrocyte

The effect of chlorpromazine (CPZ) on the shape of human erythrocytes with different values of transmembrane potential (TMP) was investigated. The shape of red blood cells with negative values of the TMP remained unchanged after the formation of stomatocytes by chlorpromazine, while cells with positive TMP showed a characteristic time course of shape change during the incubation with CPZ. Experiments with vanadate show that this might be due to a difference in the activity of the phospholipid-translocase at different values of TMP.

Spousal caregivers of dementia victims: longitudinal changes in immunity and health

Providing long-term care for a demented relative profoundly affects caregivers' lives. We assessed changes in depression, immune function, and health in 69 spousal caregivers who had already been caregiving for an average of five years and 69 sociodemographically matched control subjects. Between the initial sample ("intake") and the follow-up data collected an average of 13 months later, caregivers showed decrements relative to controls on three measures of cellular immunity. Caregivers also reported significantly more days of infectious illness, primarily upper respiratory tract infections. Caregivers had a much greater incidence of depressive disorders than controls, with 25% of caregivers meeting syndromal criteria at intake and 32% at follow-up, compared with no cases among controls at intake and 6% at follow-up. Caregivers who reported lower levels of social support at intake and who were most distressed by dementia-related behaviors showed the greatest and most uniformly negative changes in immune function at follow-up.

Stress-related activation of Epstein-Barr virus

Herpesviruses characteristically persist in a latent state in the body over the lifetime of an individual. Under certain conditions, any one of the herpesviruses can be reactivated. The mechanisms underlying the establishment of latent virus infection or viral reactivation are not well understood; however, it is known that the cellular immune response plays a very important role in the maintenance of latency and in virus reactivation. One of the factors thought to be associated with the reactivation of latent herpes-viruses is psychological stress. Using an examination stress model with medical student subjects, we previously demonstrated the reactivation of latent Epstein-Barr virus (EBV), as measured by increases in antibody titers. In this follow-up study using the same group of medical students, we found evidence for incomplete reactivation of latent EBV, with only selective expression of the latent virus genome.

Characterization of two monoclonal antibodies to Epstein-Barr virus diffuse early antigen which react to two different epitopes and have different biological function

Five monoclonal antibodies (mAbs) were identified using immunofluorescence that were specific for the Epstein-Barr virus (EBV) encoded 52/50 kDa early antigen (EA-D) protein complex. Evidence to suggest that these mAbs react with the same 52/50 kDa EA-D protein was obtained by Western blotting, immunoprecipitation and ELISA. Two of the mAbs, 90E2 and 214A9, neutralized EBV DNA polymerase activity. The 214A9 mAb also inhibited the activity of bacteriophage T4 DNA polymerase while the 90E2 mAb did not. These data suggest that the 90E2 and 214A9 mAbs recognize two different epitopes on the 52/50 kDa EA-D protein. The high frequency of recovery of hybridomas producing anti 52/50 kDa EA-D mAbs suggest that this protein may have an important role in EBV pathogenesis/replication.

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.

Effects of pyrroloisoquinoline enantiomers ((+)- and (-)-McN-5652-Z) on behavioral and pharmacological serotonergic mechanisms in rats

A behavioral syndrome consisting of 5-hydroxytryptamine (5-HT)-dependent behaviors (e.g. forepaw treading, retropulsion and splayed hindlimbs) as well as hyperthermia occurred after bilateral injection of the (6S, 10bR)-(+)-enantiomer of McN-5652-Z into the cerebral ventricles in pargyline-treated rats. Both the behavioral syndrome and hyperthermia produced by (+)-McN-5652-Z were counteracted by parachlorophenylalanine or ketanserin. The (6R, 10bS)-(-)-enantiomer of McN-5652-Z influenced neither behavior nor body temperature. The enantiomers of McN-5652-Z differed also in their ability to inhibit ex vivo binding of paroxetine in rat frontal cortex and hypothalamus, in vitro uptake of 5-HT in rat blood platelets, and 5-HT-induced contraction of rat vascular smooth muscle, with (+)-McN-5652-Z being most active. No difference was observed between the effects of (+)- and (-)-McN-5652-Z on 5-HT metabolism by rat brain monoamine oxidase. Molecular models of N-protonated enantiomers having a cis B,C-ring juncture and a B-ring chair conformation were differentiated using a hypothetical model of the 5-HT uptake area. The findings indicate that the enantiomers of McN-5652-Z are useful tools for studying the stereoselectivity of behavioral and pharmacological effects exerted by serotonergic neurotransmission.

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.

A sensitive non-isotopic assay specific for HIV-1 associated reverse transcriptase

A sensitive non-isotopic assay for specific detection of reverse transcriptase (RT) of the human immunodeficiency virus type 1 (HIV-1) is described using 5-bromo-2'-deoxyuridine triphosphate (BrdUTP) instead of tritiated thymidine triphosphate. After the RT reaction the template primer is degraded by alkaline hydrolysis. Single-stranded poly.(BrdU) is detected in an immunoenzymometric assay using monoclonal anti-BrdU antibodies. The specificity of the assay is demonstrated by the isolation of RT from virus lysate by an insolubilised monoclonal anti-HIV-1 RT antibody prior to the RT reaction. Immunological RT binding leads to a tenfold increase in analytical sensitivity since substances inhibiting the RT reaction can be removed. This non-isotopic assay is some 30 times more sensitive than the classical radioisotopic RT assay. In terms of RT determination, however, there is a good correlation between these tests (r = 0.96). Several filtrations are no longer necessary to remove non-incorporated nucleotides. The test can be adapted to microtitre plates and hence is easy to automate.

A comparison of Epstein-Barr virus specific proteins expressed by three Epstein-Barr virus isolates using specific monoclonal antibodies

Monoclonal antibodies (MAbs) were prepared in mice inoculated with a nasopharyngeal carcinoma Epstein-Barr virus (NPC-EBV) producer lymphoblastoid cell line (NPC-LC). When the 214A9 MAb was used to study the expression of the 52/50-kD early antigen in NPC-LC, B95-8, and HR-1 cells, no difference was found. The same results were obtained with the 343D12 MAb which is to a 125-kD virus capsid antigen protein. However, the 244G11 MAb detected an EBV membrane antigen (MA) with a molecular weight of 220 kD in both B95-8 and HR-1 cells, but reacted with a 250-kD MA protein in the NPC-LC cells. Similar results were obtained with the 201D6 MAb which reacted with a MA polypeptide with a molecular weight of 220/200 kD in HR-1 and B95-8 cells and one of 250/200 kD in NPC-LC cells. The data suggest that there may be differences in at least two MA proteins synthesized by the NPC-EBV isolate as compared with the prototype HR-1 and B95-8 EBV isolates.

Species-dependent differences in the influence of ionic strength on potassium transport of erythrocytes. The role of membrane fluidity and Ca2+

The passive Rb+ (K+) efflux from erythrocytes of seven mammalian species was investigated in solutions of physiological and low ionic strength. Furthermore the fluidity of the erythrocyte membrane in the same solutions was estimated by measuring the ESR order parameter. The rate constant of Rb+ (K+) efflux in solution of high ionic strength could be correlated with the order parameter obtained and with the mean number of double bonds to the membrane phospholipid fatty acids. The same relationships could be observed for the low ionic strength solutions if the values for human erythrocytes were excluded. The appearance of Na+, K+, Cl- cotransport to a significant extent, only in human erythrocytes, was supposed to be the reason for this different behaviour of human red blood cells. It was demonstrated that the strong increase of the Rb+ (K+) efflux rate constant for human erythrocytes in low ionic strength solution is not due to Ca2+, as quinine treatment and replacement of all external potassium, both inhibiting the Ca2(+)-induced K+ efflux, did not abolish the increase of (Rb+) K+ efflux in solutions of low ionic strength.

Expression of the Epstein-Barr virus genome in a nasopharyngeal carcinoma epithelial tumor cell line

An epithelial tumor cell line was recently established from a biopsy specimen of a nasopharyngeal carcinoma (NPC), and designated HONE-I. Uncloned (parental) HONE-I and HONE-I clone (C)-40 cells were found to contain latent Epstein-Barr virus (EBV). Expression of the latent EBV genome in HONE-I C-40 cells has been examined. It was possible to detect a small percentage of cells spontaneously synthesizing EBV early antigen (EA) and virus capsid antigen (VCA) by immunofluorescence (IF). In addition, the EBV nuclear antigens (EBNA-I and EBNA-2), as well as the EBV latent membrane protein (LMP) were detected in the HONE-I cells. Attempts were made to induce the latent EBV genome in these cells with iododeoxyuridine (IUdR). We observed a significant increase in the number of EA/VCA-positive cells, an increase in EBV DNA, the synthesis of virus particles, and the rescue of infectious virus after treatment of HONE-I C-40 cells with IUdR. The HONE-I C-40 cells should facilitate studies of the expression and regulation of the EBV genome in NPC epithelial tumor cells, which have not previously been available.

A monoclonal antibody that neutralizes Epstein-Barr virus, human cytomegalovirus, human herpesvirus 6, and bacteriophage T4 DNA polymerases

A monoclonal antibody (mAb) designated 55H3 was produced by using chemically induced Epstein-Barr virus genome-positive B95-8 cells. mAb 55H3, which reacted with an 85- to 80-kDa polypeptide, neutralized Epstein-Barr virus-encoded DNA polymerase activity in crude extracts of chemically induced M-ABA, HR-1, and B95-8 cells, as well as the partially purified Epstein-Barr virus DNA polymerase in a dose-dependent manner. The mAb also neutralized the virus-encoded DNA polymerase activity from cells infected with human cytomegalovirus, human herpesvirus 6, and the purified bacteriophage T4 DNA polymerases. However, mAb 55H3 did not neutralize the DNA polymerase activities encoded for by herpes simplex virus types 1 and 2, the reverse transcriptase of avian myeloblastosis virus, or Escherichia coli DNA polymerase 1 (Klenow fragment). These results suggest that mAb 55H3 recognizes an epitope common to some herpesviruses and T4 DNA polymerases and further supports the hypothesis that these organisms are evolutionarily related.

Psychological stress-induced modulation of interleukin 2 receptor gene expression and interleukin 2 production in peripheral blood leukocytes

We explored the expression of the interleukin 2 receptor (IL-2R) and the synthesis of IL-2R messenger RNA by peripheral blood leukocytes obtained from medical students experiencing examination stress in three independent studies. The peripheral blood leukocytes obtained at low-stress baseline periods had significantly higher percentages of IL-2R-positive cells when compared with cells obtained from the same individuals during examinations. In addition, IL2-R messenger RNA in peripheral blood leukocytes decreased significantly during examination periods in a subset of 13 subjects. In one study, we found an increase in the accumulation of interleukin 2 in cultures of cells showing down regulation of IL-2R expression and IL-2R messenger RNA levels. While there are ample data demonstrating stress-associated decrements in the immune response in humans and animals, these data provide the first evidence that this interaction may be observed at the level of gene expression. The data suggest one mechanism whereby the central nervous system modulates the immune response during psychological stress.

Severe hemolysis after incomplete mitral valve repair

We report 2 cases of severe intravascular hemolysis after mitral valve repair using a Duran annuloplasty ring. In both patients residual mitral regurgitation was present, hemolysis was severe enough to warrant a second operation, and hemolysis ceased immediately after the second operation. We believe that a high-velocity regurgitant jet directed toward the cloth-covered annuloplasty ring was responsible for the hemolysis in both patients.

Psychological stress and phorbol ester inhibition of radiation-induced apoptosis in human peripheral blood leukocytes

Apoptosis is a process of genetically programmed alterations of cell structure that lead to failure of proliferation and differentiation, and eventual cell death. Apoptosis is induced by a variety of toxic insults including growth factor deprivation and ionizing radiation. This process may function to protect against the appearance of heritable phenotypic changes in cells and may be a critical factor in normal cellular immune function. Phorbol esters inhibit apoptosis, but little is known about factors that regulate this process physiologically. In this study, we demonstrate an association between an acute psychological stressor, taking examinations, and the induction of substantial and reversible changes in the response of peripheral blood leukocytes to gamma irradiation and to phorbol ester treatment. These data suggest that psychological stress may induce physiological changes that regulate the ability of immune cells to initiate apoptosis.

Cannabimimetic activity of novel enantiomeric, benzofuran cannabinoids

The synthesis of the (2R,3R,4S,6R)-7/(2S,3S,4R,6S)-8 enantiomeric pair of benzofuran cannabinoids is reported together with the 1H and 13C NMR spectral parameters. In benzofuran 8 the configurational arrangement of ligated groups at the stereogenic C(3) atom (through which the terpene moiety is connected to the aromatic ring) is very similar to that of the corresponding atom in natural (3R,4R)-delta 1-tetrahydrocannabinol (delta 1-THC), although their respective Cahn-Ingold-Prelog descriptors are different. In drug-discrimination tests in pigeons and rats, benzofuran 8 is as active as delta 1-THC; in the mouse ring test compound 8 is more active than delta 6-THC. Enantiomer 7 is considerably less active than enantiomer 8 in both tests. These results can be explained by the fact that both 7 and 8 have a dimethylheptyl side chain (which is known to enhance cannabimimetic activity) and that delta 1-THC and benzofuran 8 have closely related conformations, as determined by molecular mechanics.