stress virus demyelination multiple sclerosis
Fundamentals

Effect of Psychological Stress On Neuro-Immune Connections in Virus-Induced Demyelination: Implications for Multiple Sclerosis and Autoimmune Diseases

, , and ·

Abstract

Psychological stress plays a role in the pathogenesis of several autoimmune disorders. In this overview, we will describe our research into the mechanisms by which stress can alter disease pathogenesis in a mouse model of multiple sclerosis: Theiler’s murine encephalomyelitis virus-induced demyelinating disease.

Restraint stress was applied to various strains of mice and immune measures, and clinical outcomes were assessed. Stress induced high levels of glucocorticoids, which decreased both innate and adaptive immune responses to the virus.  Overall, stress was demonstrated to increase viral load in the central nervous system of Theiler’s virus infected mice, which in turn led to more severe demyelinating disease. Stressed infected-mice also developed cardiac lesions, not present in the infected-unstressed mice suggesting altered viral pathogenesis. Our findings may have implications for understanding the role of stress in the development of pathogen-induced autoimmunity.

Multiple sclerosis (MS) is an inflammatory demyelinating neurodegenerative disease of the central nervous system (CNS) occurring at a prevalence of 400,000 in the US (1,2). The incidence of MS appears to be increasing from 1/2000 to 1/1000 (3).  Epidemiological studies of MS indicate that important risk factors are, MHC Class II genes, low serum levels of vitamin D, smoking and childhood obesity (4). A viral etiology for MS has long been inferred (5) and Epstein–Barr virus has recently been strongly implicated in a study with 10 million service personnel, which showed a 32-fold increase in risk of developing MS following EBV infection (6).

Since the earliest descriptions of MS (7), stress was recognized as an initiating factor in the disease onset and progression (8). Stressful life events have been described prior to the development of MS symptoms (9), and psychological stress has been reported to precede both the onset and recurrence of MS symptoms (10,11). A prospective study indicated that MS patients experiencing three or more stressful life events within a one-month timeframe, had a 5-fold increase in exacerbation risk (12).

These studies are supported by investigations correlating major negative stressful life events with the appearance of new and enlarging lesions as determined by MRI (13,14). A meta-analysis of 14 papers that examined the effects of stress on MS, concluded that there was “a significantly increased risk of exacerbation associated with stressful life events” (15). Importantly, a randomized clinical trial of stress management prevented new brain lesions in MS patients receiving stress management compared to the control group (16). These findings provide more conclusive evidence for the link between stress and MRI activity because a RCT design eliminates potential biases that limit the explanatory power of epidemiologic studies (16).

Theiler’s virus-induced demyelination (TVID) as a model for MS

Theiler’s murine encephalomyelitis virus (TMEV) is a Picornavirus that causes an asymptomatic gastrointestinal infection and occasionally paralysis, in mice (17). It is classified as a Cardiovirus within the family Picornaviridae and has been shown to cause cardiomyopathy (18). Intracerebral infection with the persistent strains of Theiler’s virus (BeAn, DA) causes a primary demyelinating disease in susceptible strains of mice. The inflammatory demyelinating lesions are similar to those seen in MS (19). In C57BL/6 mice, Theiler’s virus induces epilepsy, but this mouse strain clears the infection effectively from the CNS and is resistant to the demyelinating disease (20). The TVID represents a useful model with which to investigate how environment may affect virus-induced demyelination.

Restraint stress activates the hypothalamus-pituitary-adrenal axis and results in increased sickness behavior following Theiler’s virus infection

In order to determine the effects of psychological stress on the disease course of Theiler’s virus infection, we used a restraint stress model originally described by Sheridan and colleagues (21,22). Stress had a profound effect on survival following infection with Theiler’s virus. Stressed-infected CBA mice suffered increased mortality, increased signs of sickness behavior, higher viral titers in the CNS (log 4 to log 7), significant adrenal hypertrophy, splenic and thymic atrophy, increased plasma glucocorticoid levels, decreased numbers of circulating lymphocytes and increased circulating neutrophils (23,24,25). Although the histopathologic brain lesions were similar in character in both the infected/restrained group and the infected/non-restrained group at day 7, the inflammation was more severe in the infected/non-restrained mice (23). The lesions in all the infected mice were characterized by neuronal degeneration, parenchymal perivascular cuffing, microgliosis, meningitis, and astrocytosis, hypertropy/hyperplasia. Lesions were most evident in the hippocampus and the deep regions of the dorsal cerebral cortex – known areas of viral tropism for this strain of Theiler’s virus. Microgliosis and perivascular cuffing in the hippocampus and the adjacent parenchyma were also present. Accompanying the appearance of inflammation, immunostaining revealed viral antigens in pyramidal cells of the hippocampus. In the mice that were infected but not restrained, there was a pronounced increased incidence and severity of microgliosis and perivascular cuffing (23).

As a result of these studies, we postulated that restraint stress activated the hypothalamus-pituitary-adrenal axis (HPA) resulting in increased glucocorticoid levels, which in turn led to immunosuppression, decreased immune cell infiltration into the CNS, increased viral titers and mortality from encephalitis. Exogenous application of glucocorticoid in the drinking water produced 100% mortality by day 17 post-infection with Theiler’s virus, which implicated the HPA axis activation pathway in the pathogenesis of stress-enhanced mortality (26). We also reversed the detrimental effects of stress with RU486, which blocks glucocorticoids binding to the glucocorticoid receptor, (26) and so we focused on the role of glucocorticoids for the remainder of this work and did not investigate the role of catecholamines.

Restraint stress decreases the innate immune response to Theiler’s virus

Having established that restraint stress impacts the neuropathogenesis of Theiler’s virus infection, we “dissected” the effects of stress on the specific components of the immune response to Theiler’s virus. The early activation of the immunological/inflammatory events in Theiler’s virus infection, determine the effective clearance of virus from the CNS. In strains of mice where there is ineffective viral clearance (SJL and CBA) due to inadequate immune activation, persistent infection of the CNS is established which results in subsequent demyelination (27,28,29). Therefore, the early innate response to Theiler’s virus infection sets the stage for either the resolution of infection or the development of the later chronic demyelinating disease.

Natural killer cells are acutely sensitive to chronic stress in our model. We observed that restraint stress applied 24 hours prior to infection with Theiler’s virus resulted in 50% reduction in splenic NK cell activity in CBA mice when measured 24 hours post infection, compared to infected/non-restraint stress mice (30).  Additionally, we found that this stressor also resulted in significant decreased numbers of IFN-γ producing NK cells infiltrating the CNS, which correlated with higher viral titers. The reduction in NK cells has been shown to be mediated by norepinephrine (31,32).

Restraint stress reduces pro-inflammatory chemokine/cytokine expression

We then examined the effects of stress on early chemokine/cytokine expression in the CNS and periphery using the spleen as an indicator of peripheral immune activation22,31.  Expression of Ltn (Cxcl1), RANTES (Ccl5) and IP-10 (Cxcl10) were significantly decreased in the brain of stressed mice (24).  Ltn, RANTES and IP-10 recruit NK cells, macrophages, CD4+ and CD8+ T cells. Decreased levels of these chemokines in the brain of stressed mice, may result in decreased inflammatory cell infiltrate into the CNS and subsequently reduced viral clearance and increased mortality (24).  Restraint attenuated the virus-induced increases of the following cytokines: IFN-γ (Ifng) LT-β (Ltβ), IL-12p40 (Il12b), and IL-6 (Il6), but elevated IFN-β (Ifnb) (33).

We postulated that the observed increased mRNA IFN-β levels in the brains of infected-stressed mice may result from the increased viral titers that develop in stressed mice, and this would stimulate the production of this interferon. In further experiments, mice were subjected to the restraint stress model, and, at termination, half the brain removed and stored at -800C for viral plaque assays. RNase protection assay (RPA) analysis of the remaining half of the brain revealed that mRNA levels of IFN-γ, LT-b, and TNF-α, negatively correlated with viral titers in the CNS. The mice with higher brain cytokine levels were more effective at viral clearance. Western blot analysis confirmed the RPA data for TNF-α protein levels (33). To summarize, these results demonstrate that restraint stress reduces the expression of cytokines involved in the transition from innate to adaptive immunity (IFN-γ and IL-12) and also cytokines that directly inhibit viral replication (IFN-γ and TNF-α).

Restraint stress facilitates systemic dissemination of Theiler’s virus

The effect of restraint stress on the systemic dissemination of Theiler’s virus in CBA mice was also investigated (34).  Restraint stressed infected mice developed higher viral titers in the brain and spinal cord by day 7 p.i. and significantly increased viral titers in the spleen, lymph nodes, thymus, lungs and heart. Viral clearance from those organs/tissues was also impaired by stress.  Interestingly, higher myocardial viral titers and granular degeneration of the myocardium were observed in infected/restraint -stressed mice.  These results demonstrate the profound effect of restraint stress on both organ tropism and the dissemination of the Theiler’s virus.  We hypothesized that since the increased levels of viral replication in the stressed mice, allows for increased rates of viral mutations and the possibility of the generation of viruses with the acquired ability to infect the heart and result in the cardiac pathology noted in these mice. The fact that stress alters the pathogenesis of Theiler’s virus infection may have important implications for other disease processes.  A stressed patient may develop altered disease manifestations as the causative agent is able to mutate and infect additional organs and tissues.

Restraint stress reduces adaptive immune responses to Theiler’s virus

In the acute infection with Theiler’s virus, CD4+ T cells are critical in mediating viral clearance through at least two mechanisms: assisting B cells in the production of antibodies and producing IFN-γ, an effective inhibitor of Theiler’s virus infection in vitro (35) and in vivo (36,37).  Cytotoxic CD8+ T cells also mediate viral clearance as demonstrated by the fact that CD8+ depleted mice fail to clear virus from the CNS and develop more severe demyelination compared to immunocompetent controls (38).

Due to the critical nature of both CD4+ and CD8+ T cells in Theiler’s virus infection, we explored the effect of restraint stress in SJL mice since the immunodominant Theiler’s virus specific T cell epitopes have been identified in this mouse strain (39,40,41) which allows for ease of discrimination between CD8 and CD4 T cell responses. We observed that restraint stress decreased significantly, both the virus induced CD4 and CD8 T cell responses in the spleen and the CD8+ T cell responses within the CNS (42).

Figure 1 Stress Virus Induced Demyelination readyFigure 1: Effects of stress on antiviral immunity. Stress is perceived by the brain (1) and activates the hypothalamus pituitary adrenal axis resulting in the release of glucocorticoids (2). CNS chemokines CCL2 and CCL5 are decreased and also the cytokines IFN-γ and TNF-α are decreased (denoted in red). Elevation of glucocorticoids act to inhibit NK cells and virus-specific T and B cell responses (3). Concomitantly stress upregulates hematopoietic factors that drive neutrophilia (CXCL-1, G-CSF and IL-6 denoted in green) (4). Collectively the effects of stress create a scenario that favors viral replication and dissemination (5).

To determine whether stress differentially affects Th1 responses and Th2 responses, we examined the expression of both Th1 and Th2 cytokines indirectly by measuring the transcription factors T-bet and GATA-3- the drivers of Th1 and Th2 polarization, respectively (43,44). Splenic mRNA and protein expression levels of both these factors were found to decrease significantly in restraint stressed mice at day eight post infection (40).  Restraint stress also significantly decreased both Type 1 {IL-12(p40), IL-12(p70), IFN-γ} and Type 2 (IL-4 and IL-5) serum protein concentrations as well as RANTES and MCP-1 (CCL2). Stress increased the growth factor G-CSF and chemokine KC (CXCL1). KC is involved in trafficking of neutrophils, and the hematopoietic factor G-CSF is, in part, responsible for the maturation of neutrophils from the bone marrow. The stress-induced increases in serum levels of KC (CXCL1) and G-CSF may explain the increase in neutrophils in the blood of restraint stressed mice we had previously observed (23).

Restraint stress during acute infection exacerbates the later demyelinating disease

All our research described to this point, has focused on the effects of stress on the acute infection with Theiler’s virus. It was then vital to explore the effects of stress on the late demyelinating disease, which models MS. Previous studies showed that increased viral load during acute disease (due to CD8+ T cell depletion) which leads to more severe later demyelinating disease (38). Thus, we hypothesized that since stress results in higher viral load in the CNS, this would subsequently lead to increased demyelination.

To test this hypothesis, we subjected male and female SJL/J mice to either normal housing conditions or restraint stress for four weeks during the acute phase of infection, then monitored the course of disease using behavioral testing. During the early phase of disease, we observed comparable results to the earlier experiments with CBA mice. During the first month of infection, both male and female stressed mice developed decreased body weights and locomotor activity, with increased behavioral signs of illness and plasma glucocorticoid levels.  In the later demyelinating phase of the disease, previously stressed mice had increased behavioral signs of demyelination and increased inflammatory demyelinating lesions of the spinal cord (25,45).

Correlational analysis demonstrated that in the acute phase of disease in SJL mice, plasma glucocorticoid levels, were highly correlated with: meningitis, rotarod performance, and clinical signs of demyelination in the chronic phase of disease.  In another experiment with restraint-stressed SJL mice we also observed higher viral loads in the CNS at day 25 p.i. as compared to non-stressed, Theiler’s-infected mice (45).  Thus, we propose that the stressed mice that develop the higher glucocorticoid levels, develop more severe immunosuppression, allowing for increased viral replication and consequently more severe inflammatory demyelinating disease.

Conclusions

Summarizing all the research to date on the effects of stress on the neuropathogenesis of Theiler’s virus, we have developed the following hypothesis: stress activates the hypothalamus-pituitary-adrenal axis, resulting in increased glucocorticoid production, immunosuppression in both innate and adaptive components of the immune system (Figure 1). The immunosuppressive effects of stress allowed for increased viral replication, resulting in higher viral load in the CNS and therefore more severe later demyelinating disease. It may also allow an increased chance for the pathogen to gain access to organs or tissues not routinely infected.

The relevance of these findings maybe applicable to our understanding of MS and other autoimmune diseases triggered by infectious agents. MS is a multifactorial disease and stress maybe an important factor in disease development. The first step in the pathogenesis of autoimmunity is genetic background. In the case of MS, the possession of MHC Class II gene DRB1*15:01, is a very important risk factor (46). The second step would be suffering severe stressful life events, leading to generalized immunosuppression which will render an individual more susceptible to viral infections. Immunosuppression provides the opportunity for the pathogen to replicate to higher levels and thereby gain access to the target organ. Unchecked viral replication allows the development of mutant progeny that may have enhanced pathogenicity allowing for novel unexpected disease outcomes.

Key words: psychological stress, multiple sclerosis, Theiler’s virus infection

Authors’ Affiliations:

Jane Welsh, Department of Veterinary Integrative Biosciences, College of Veterinary Medicine & Biomedical Sciences; Department of Veterinary Pathobiology, College of Veterinary Medicine & Biomedical Sciences; Texas A&M Institute for Neuroscience, Texas A&M University, USA.

Andrew J. Steelman, Department of Animal Sciences, University of Illinois, Urbana-Champaign, USA.

Colin R. Young, Department of Veterinary Integrative Biosciences, College of Veterinary Medicine & Biomedical Sciences, USA.

Mary W. Meagher, Texas A&M Institute for Neuroscience, Texas A&M University; Department of Psychological & Brain Sciences, College of Arts & Sciences, USA.

Acknowledgements

This research was funded by grants to C.J.R.W. and M.W.M. from the National Multiple Sclerosis Society RG 3128, NIH/NINDS R01 39569 and NIH/NINDS R01-NS060822 to M.W.M and C.J.R.W.

References
  1. D.W. Anderson, J.H. Ellenberg, C.M. Leventhal, S.C. Reingold, M. Rodriguez, D.H. Silberberg, Revised estimate of the prevalence of multiple sclerosis in the United States, Ann. Neurol. 31 (1992) 333-336.
  2. B.G., Weinshenker, Epidemiology of multiple sclerosis, Neurol. Clin. 14 (1996) 291–308.
  3. P. Browne, D. Chandraratna, C. Angood, et al., Atlas of multiple sclerosis 2013: a growing global problem with widespread inequity. Neurology 83 (2014) 1022–1024
  4. T.O. Tobore, Towards a comprehensive etiopathogenetic and pathophysiological theory of multiple sclerosis. Int J Neurosci. 130 (2020) 279-300.
  5. M. Marrodan, L. Alessandro, M.F. Farez, J. Correale, The role of infections in multiple sclerosis, Mult. Scler. 25 (2019) 891-901.
  6. K. Bjornevik, et al., Longitudinal analysis reveals high prevalence of Epstein–Barr virus associated with multiple sclerosis. Science. (2022) 375 296–301.
  7. A-M, Landtblom, P. Fazio, S. Fredrikson, E. Granieri, The first case history of multiple sclerosis: Augustus d’Este (1794–1848). Neurol Sci 31 (2010) 29–33
  8. I. Grant, Psychosomatic-somatopsychic aspects of multiple sclerosis In: ed. U. Hailbreich, Multiple sclerosis: A Neuropsychiatric Disorder. American Psychiatric Press, Washington. (1993) 119-136
  9. S. Warren, S. Greenhill, K.G. Warren, Emotional stress and the development of multiple sclerosis: case-control evidence of a relationship, J. Chronic Dis. 35 (1982) 821-831.
  10. K.D. Ackerman, A. Stover, R. Heyman, B.P. Anderson, P.R. Houck, E. Frank, B.S. Rabin, A. Baum, R. Ader New Investigator award. Relationship of cardiovascular reactivity, stressful life events, and multiple sclerosis disease activity, Brain Behav. Immun. 17 (2003) 141-51.
  11. J. Li, C. Johansen, H. Bronnum-Hansen, E. Stengar, N. Koch-Henriksen, J. Olsen, The risk of multiple sclerosis in bereaved parents: A nationwide cohort study in Denmark, Neurology 62 (2004) 726-729.
  12. C.I. Mitsonis, I.M. Zervas, P.A. Mitropoulos, N.O. Dimopoulos, C.R. Soldatos, C.M. Potagas et al., The impact of stressful life events on risk of relapse in women with multiple sclerosis: A prospective study, European psychiatry 23 (2008) 497-504.
  13. Mohr DC, Goodkin DE, Bacchetti P, et al. Psychological stress and the subsequent appearance of new brain MRI lesions in MS. Neurology, 55 (2000) 55– 61.
  14. Mohr DC. The relationship between stressful life events and inflammation in patients with multiple sclerosis. In: Welsh CJ, Meagher M, Sternberg E, ed. Neural and Neuroendocrine Mechanisms in Host Defense and Autoimmunity. New York: Kluwer Academic/Plenum Publishers (2006) 255–267.
  15. D.C. Mohr, S.L. Hart, L. Julian, D. Cox, D. Pelletier, Association between stressful life events and exacerbation in Multiple Sclerosis: a meta-analysis, B.M.J., 328 (2004) 731-735.
  16. D. C. Mohr, J. Lovera, E. Brown, B. Cohen, T. Neylan, R. Henry, J. Siddique, L. Jin, D. Daikh, D. Pelletier, A randomized trial of stress management for the prevention of new brain lesions in MS. Neurology 79 (2012) 412-419.
  17. M. Theiler, Spontaneous encephalomyelitis of mice- a new virus, Science 80 (1934) 122.
  18. R.M. Gomez, J.E. Rhinehart, R. Wollmann, R.P. Roos, Theiler’s murine encephalomyelitis virus-induced cardiac and skeletal muscle disease J. Virol 70 (1996) 8926-33.
  19. H.L. Lipton, Theiler’s virus infection in mice: an unusual biphasic disease process leading to demyelination, Infect. Immun. 11 (1975) 1147-1155.
  20. K.A. Stewart, K.S. Wilcox, R.S. Fujinami, H.S. White, H.S., Development of post infection epilepsy after Theiler’s virus infection of C57BL/6 mice J. neuropath and expt neurol 69, (2010) 1210-1219
  21. J.F. Sheridan, N. Feng, R.H. Bonneau, C.M. Allen, Restraint stress differentially affects anti-viral cellular and humoral immune responses in mice, J. Neuroimmunol. 31 (1991) 245-255.
  22. J.F. Sheridan, N. Feng, R.H. Bonneau, C.M. Allen, Restraint stress differentially affects anti-viral cellular and humoral immune responses in mice, J. Neuroimmunol. 31 (1991) 245-255.
  23. T. Campbell, M.W. Meagher, A. Sieve, B. Scott, R. Storts, T.H. Welsh, T.H., C.J.R. Welsh, The effects of restraint stress on the neuropathogenesis of Theiler’s virus-induced demyelination. I.  Acute disease, Brain Behav. Immun. 15 (2001) 235-254.
  24. W. Mi, M. Belyavskyi, R.R. Johnson, A.N. Sieve, R. Storts, M.W. Meagher, C.J.R. Welsh, Alterations in chemokine expression in Theiler’s virus infection and restraint stress, J. Neuroimmunol. 151 (2004) 103-115.
  25. A.N. Sieve, A. J. Steelman, C.R. Young, R. Storts, T.H. Welsh, C.J.R. Welsh, M.W. Meagher, Chronic restraint stress during early Theiler’s virus infection exacerbates the subsequent demyelinating disease in SJL mice, J. Neuroimmunol. 155 (2004) 103-118.
  26. E. E. Young, T. W. Prentice, D. Satterlee, H. McCullough, A.N. Sieve, R.R. Johnson, T.H. Welsh, C.J.R. Welsh, and M.W. Meagher, Glucocorticoid exposure alters the pathogenesis of Theiler’s murine encephalomyelitis virus during acute infection. Physiology and Behavior 95 (2008) 63-71.
  27. C.J.R. Welsh, W.F. Blakemore, P. Tonks, P., Borrow, A.A. Nash, Theiler’s murine encephalomyelitis virus infection in mice: a persistent viral infection of the central nervous system which induces demyelination. In: Immune responses, Virus Infection and Disease (1989) pp125-147. Published by Oxford University Press.  Editor: Nigel Dimmock.
  28. M. Brahic, W.G. Stroop, J.R. Baringer, Theiler’s virus persists in glial cells during demyelinating disease, Cell 26 (1981) 123-128.
  29. M. Rodriguez, K.D. Pavelko, M.K. Njenga, W.C. Logan, P.J. Wettstein, The balance between persistent virus infection and immune cells determines demyelination, J. Immunol. 157 (1996) 5699-5709.
  30. C.J.R. Welsh, L. Bustamante, M. Nayak, T.H. Welsh, D.D. Dean, D.D., M.W. Meagher, The effects of restraint stress on the neuropathogenesis of Theiler’s virus infection II: NK cell function and cytokine levels in acute disease, Brain Behav. Immun. 18 (2004) 166-174.
  31. B.A. Esterling, J.K., Kiecolt-Glaser, R. Glaser. Psychosocial modulation of cytokine-induced NK cell activity in older adults. Psychosom Med., 58 (1996) 264-72.
  32. X. Gan, L. Zhang, G.F. Solomon, B. Bonavida, Mechanism of norepinephrine-mediated inhibition of human NK cytotoxic functions: inhibition of cytokine secretion, target binding, and programming for cytotoxicity. Brain Behav Immun 6 (2002) 227-46.
  33. W. Mi, T.W. Prentice, C.R. Young, R.R. Johnson, A.N. Sieve, M.W. Meagher, C.J.R. Welsh, Restraint stress decreases virus-induced pro-inflammatory cytokine expression during acute Theiler’s virus infection, J. Neuroimmunol. 178 (2006) 49-61.
  34. W. Mi, C.R. Young, R., Storts, A. Steelman, M.W. Meagher, C.J.R. Welsh, Stress alters pathogenecity and facilitates systemic dissemination of Theiler’s virus, Microb. Path. 41 (2006) 133-143.
  35. C.J.R. Welsh, B.V. Sapatino, B. Rosenbaum, R. Smith, Characteristics of cloned cerebrovascular endothelial cells following infection with Theiler’s virus. I. Acute Infection, J. Neuroimmunol. 62 (1995) 119-125.
  36. M. Kohanawa, A. Nakane, T. Minagawa, Endogenous gamma interferon produced in central nervous system by systemic infection with Theiler’s virus in mice, J. Neuroimmunol. 48 (1993) 205-211.
  37. M. Rodriguez, K. Pavelko, R.L. Coffman, Gamma interferon is critical for resistance to Theiler’s virus-induced demyelination, J. Virol. 69 (1995) 7286-7290.
  38. P. Borrow, P. Tonks, C.J.R. Welsh, A.A. Nash, The role of CD8+ T cells in the acute and chronic phases of Theiler’s virus-induced disease in mice, J gen. Virol. 73 (1992) 1861-1865.
  39. B.S. Kang, M.A. Lyman, B.S. Kim, Differences in avidity and epitope recognition of CD8(+) T cells infiltrating the central nervous systems of SJL/J mice infected with BeAn and DA strains of Theiler’s murine encephalomyelitis virus, J. Virol. 76 (2002) 11780-11784.
  40. S.J. Gerety, R.J. Clatch, H.L. Lipton, R.G. Goswami, M.K. Rundell, S.D. Miller, Class II-restricted T cell responses in Theiler’s murine encephalomyelitis virus-induced demyelinating disease IV. Identification of an immunodominant T cell determinant on the N-terminal end of the VP2 capsid protein in susceptible SJL/J mice, J. Immunol. 146, (1991) 2401-2408.
  41. S. Gerety, W. Karpus, A.R. Cubbon, R. Goswami, M.K. Rundell, J. Peterson, S.D. Miller, Class II-restricted T cell responses in Theiler’s murine encephalomyelitis virus-induced demyelinating disease V. Mapping of a dominant immunopathological VP2 T cell epitope in susceptible mice, J. Immunol. 152 (1994) 908-918.
  42. A.J. Steelman, D.D. Dean, C.R. Young, R. Smith, T.W. Prentice, M.W. Meagher, C.J.R. Welsh, Restraint stress modulates virus specific adaptive immunity during acute Theiler’s virus infection, Brain, Behavior and Immun. 23 (2009) 830-843.
  43. W. Zheng, R.A. Flavell, The transcription factor GATA-3 is necessary and sufficient for Th2 cytokine gene expression in CD 4 T cells, Cell 89 (1997) 587-596.
  44. S.J. Szabo, S.T. Kim, G.L. Costa, X. Zhang, C.G. Fathman, L.H. Glimcher, A novel transcription factor, T-bet, directs Th1 lineage commitment, Cell 100 (2000) 655-669.
  45. E.E. Young, A.N. Sieve, E.G. Vichaya, L.M. Carcoba, C.R. Young, A. Ambrus, R, Storts, C.J.R. Welsh, M.W. Meagher, Chronic restraint stress during early Theiler’s virus infection exacerbates the subsequent demyelinating disease in SJL mice:  II. CNS disease severity. J. Neuroimmun. 220 (2010) 79-89.
  46. R. Martin, M. Sosperdra, T. Eiermann, T. Olsson, Multiple sclerosis: doubling down on MHC. Trends in Genetics, 37 (2021) 784-797. DOI: 10.1016/j.tig.2021.04.012