AIM2 Co-immunization with VP1 Is Associated with Increased Memory CD8 T Cells and Mounts Long Lasting Protection against Coxsackievirus B3 Challenge.

The recurrent Coxsackievirus B3 (CVB3) infection is the most important cause of intractable myocarditis which often leads to chronic myocarditis and even dilated cardiomyopathy. Therefore, enhanced DNA vaccines capable of memory CD8 T cells are essential for long-lasting immunological protection against CVB3 infection. In this study, absent in melanoma 2 (AIM2) was used as an adjuvant to enhance the induction of memory CD8 T cells elicited by VP1 (viral capsid protein 1) vaccine. Mice were intramuscularly injected with 50 µg AIM2 plasmid and equal amount of VP1 plasmid (pAIM2/pVP1) vaccine 4 times at 2 week-intervals. We observed that the protection of pAIM2/pVP1 vaccine against CVB3 challenge was evidenced by significantly improved cardiac function, reduced myocardial injuries, and increased survival rate when compared with immunization with pVP1. Co-immunization with pAIM2/pVP1 robustly augmented T lymphocytes proliferation and CVB3-specific cytotoxic T lymphocyte responses. Importantly, 16 weeks after the last immunization, pAIM2/pVP1 co-immunization significantly enhanced the expression of Bcl-6, SOCS3, and Sca-1 which are critical for memory CD8 T cells as compared with pVP1 immunization. Notably, CD8 T cells that are likely vaccine-induced memory T cells were responsible for the protective efficacy of pAIM2/pVP1 vaccine by abolition of a CD8 T cell immune response following a lethal dose of CVB3 infection. Our results indicate that AIM2-adjuvanted vaccine could be a potential and promising approach to promote a long-lasting protection against CVB3-induced myocarditis.

Optimized production and purification of Coxsackievirus B1 vaccine and its preclinical evaluation in a mouse model.

Coxsackie B viruses are among the most common enteroviruses, causing a wide range of diseases. Recent studies have also suggested that they may contribute to the development of type 1 diabetes. Vaccination would provide an effective way to prevent CVB infections, and the objective of this study was to develop an efficient vaccine production protocol for the generation of novel CVB vaccines. Various steps in the production of a formalin-inactivated Coxsackievirus B1 (CVB1) vaccine were optimized including the Multiplicity Of Infection (MOI) used for virus amplification, virus cultivation time, type of cell growth medium, virus purification method and formulation of the purified virus. Safety and immunogenicity of the formalin inactivated CVB1 vaccine was characterized in a mouse model. Two of the developed methods were found to be optimal for virus purification: the first employed PEG-precipitation followed by gelatin-chromatography and sucrose cushion pelleting (three-step protocol), yielding 19-fold increase in virus concentration (0.06µg/cm2) as compared to gold standard method. The second method utilized tandem sucrose pelleting without a PEG precipitation step, yielding 83-fold increase in virus concentration (0.24µg/cm2), but it was more labor-intensive and cannot be efficiently scaled up. Both protocols provide radically higher virus yields compared with traditional virus purification protocols involving PEG-precipitation and sucrose gradient ultracentrifugation. Formalin inactivation of CVB1 produced a vaccine that induced a strong, virus-neutralizing antibody response in vaccinated mice, which protected against challenge with CVB1 virus. Altogether, these results provide valuable information for the development of new enterovirus vaccines.

Protective effects of Wusen Erlian granules in experimental model of viral myocarditis.

We wished to study the protective effects of Wusen Erlian granules, a therapy from traditional Chinese medicine, in experimental viral myocarditis (VMC). Sixty mice were divided into six groups: control group, infection group, ribavirin group, and three Wusen Erlian groups, treated with low, intermediate, or high doses (4, 12, or 20 mg/kg) of Wusen Erlian. Control animals were intraperitoneally injected with culture medium, while animals in other groups received intraperinoneal injections of CoxB3 virus. The Wusen Erlian granules were intragastrically administered on days 0, 1, 2, 3, 4, and 5 after virus inoculation. The experiment was terminated 2 h after the final drug administration. The mice were weighed, and specimens were collected for detection of myocardial enzymes, measurement of organ index, and natural killer (NK) cell activity. The levels of creatine kinase isoenzyme, troponin, and myoglobin were significantly increased in infected animals (all p < 0.05). Compared with infection group, the levels of creatine kinase isoenzyme and troponin were significantly (p < 0.05) decreased in animals that received ribavirin, and in animals that received high or intermediate dose of Wusen Erlian. Furthermore, the spleen and thymus indexes were increased in animals treated with ribavirin, or high/intermediate doses of Wusen Erlian, suggesting immunoregulating functions of these drugs. The NK cell activity was also markedly increased in the above three groups. Wusen Erlian alleviates the CoxB3-induced myocardial injury and exhibits immunoregulating features, leading to protective effects toward myocardial cells in experimental VMC.

In vitro activity of Paris polyphylla smith against enterovirus 71 and coxsackievirus B3 and its immune modulation.

Enterovirus 71 (EV71) and coxsackievirus B3 (CVB3) have resulted in severe pathogenesis caused by the host's immune response, including the cytokine cascade. Paris polyphylla Smith is a folk medicinal plant in Asia traditionally prescribed for the reduction of pain and elimination of poisoning. In this study, we investigated the anti-EV71 and CVB3 activity of P. polyphylla Smith as well as its immune modulation. The IC(50) for the P. polyphylla Smith 95% ethanol extract against EV71 and CVB3 were 12.5-23% and 99-156% of that of ribavirin, a positive control. Prevention of viral infection, viral inactivation, and anti-viral replication effects against both EV71 and CVB3 were demonstrated by the extract, the anti-viral replication effect being dominant. The extract significantly increased IL-6 production in both EV71- and CVB3-infected cells. A high correlation was possibly demonstrated between the high amounts of IL-6 induction in the EV71 and CVB3-infected cells and the anti-viral replication activity of the extract. In conclusion, good anti-EV71 and CVB3 activity was observed in the P. polyphylla Smith 95% ethanol extract. The high amounts of IL-6 induction in the virus-infected cells played a key role in the anti-viral activity of the extract.

Beta-androstenes and resistance to viral and bacterial infections.

This report illustrates that the beta-androstenes are indeed able to upregulate the host immune response to a level that enables the host to resist lethal infection by viruses or bacteria. These agents consist of a subgroup of steroids, which also mediates a rapid recovery of hematopoietic precursor cells after whole-body lethal radiation injury. In vivo, the androstenes increase the levels of the Th1 cytokines such as IL-2, IL-3, and IFN. Similar to hydrocortisone, they suppress inflammation, but without immune suppression, and have a role in the maintenance of the Th1/Th2 balance and immune homeostasis.

[Th cell differentiation in chronic stage of viral myocarditis in mice and interference of Qingxin-II Recipe].

OBJECTIVE: To investigate part mechanisms of Th cell differentiation, and to observe the interference effect of Qingxin-II Recipe in the chronic stage of viral myocarditis (VMC), so as to provide some experimental evidences for illuminating the pathogenesis of VMC and treatment mechanisms of Qingxin-II Recipe. METHODS: According to 20%-40% death rate of experiment in advance, 100 BALB/c male mice (4 weeks old and weighing 12-15 g) were used. Twenty mice were randomly assigned to normal control group, and the other 80 mice were intraperitoneally injected with 0.1 ml normal saline containing coxsackie virus B3 at the 1st, 4th and 28th day (the virus densities were 1:2000, 1:1000 and 1:500 respectively) to induce chronic VMC. At the 42nd day, the surviving mice were randomly divided into untreated group and treatment group, with 20 mice in each group. Mice in the treatment group were orally administered with 0.2 ml Qingxin-II Recipe every day, while mice in the normal control group and the untreated group were administered with 0.2 ml normal saline. All the mice were sacrificed after 45 days, and the sera, heart and spleen cells were collected. Then the myocardial pathological changes were observed by using a light microscope, and the levels of IL-4, IL-10 and IFN-gamma in serum were detected by enzyme linked immunosorbent assay (ELISA). And the Th cell differentiation was observed by flow cytometry. RESULTS: No obvious myocardial pathological changes were observed in mice of the normal control group. Myocardial pathological changes in the treatment group were slighter than those in the untreated group. The difference of serum IL-10 level between the normal control group and the untreated group showed no significance (P>0.05), and the levels of IFN-gamma and IL-4 of the untreated group were higher than those of the normal control group (P<0.05 or P<0.01). There was no statistical difference in IL-10 level between the treatment group and the untreated group (P>0.05), while the serum levels of IL-4 and IFN-gamma of the treatment group were lower than those of the untreated group (P<0.05 or P<0.01). There was no significant difference of the Th1 cell responder between the treatment group and the untreated group (P>0.05), while the Th2 cell responder was inhibited significantly in the treatment group (P<0.05). CONCLUSION: Qingxin-II Recipe can restore the balance of Thl and Th2 cells through inhibiting the reaction of Th2.

Animal models for autoimmune myocarditis and autoimmune thyroiditis.

This chapter describes four murine models of autoimmune diseases: two related to autoimmune myocarditis and two related to autoimmune thyroiditis. The first model, Coxsackie virus B3 (CB3)-induced myocarditis, results in the development of acute myocarditis in susceptible as well as resistant mouse strains, whereas chronic myocarditis develops only in genetically susceptible mice. CB3-induced myocarditis closely resembles the course of human myocarditis, which is believed to be initiated by viral infection. Mouse cardiac myosin heavy chain has been identified as the major antigen associated with the late chronic phase of viral myocarditis. The second model is cardiac myosin-induced experimental autoimmune myocarditis (EAM) and, in a modification, cardiac alpha-myosin heavy chain peptide-induced myocarditis. In the EAM model, cardiac myosin or the relevant peptide in Freund's complete adjuvant (FCA) is injected subcutaneously into mice. The immune response, the histological changes, and the genetic susceptibility seen in EAM are similar to those of CB3-induced myocarditis. The third model is experimental autoimmune thyroiditis (EAT). EAT can be induced in genetically susceptible strains of mice by immunization with mouse thyroglobulin in FCA or lipopolysaccharide. Mice susceptible to EAT have the H-2A(k), H-2A(s), or H-2A(q) alleles. We describe here a standard technique for the induction of EAT; it was developed in our laboratory and is widely used as a model for studying Hashimoto's thyroiditis. The fourth model presented in this chapter is that of spontaneous autoimmune thyroiditis in NOD.H2h4 mice. These mice express the H-2A(k) allele on an NOD genetic background and develop spontaneous thyroiditis, which is exacerbated with dietary iodine.

Effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin on trace elements, inflammation and viral clearance in the myocardium during coxsackievirus B3 infection in mice.

A myocarditic coxsackievirus B3 (CB3) infection in adult male A/J mice was used to investigate the effects of 2,3,7,8-tetrachlorodibenzo-para-dioxin (TCDD) exposure on mortality and on inflammatory lesion, virus and trace element contents of the heart. The mice were injected with four weekly intraperitoneal (i.p.) injections of TCDD (a loading dose of 5 microg/kg followed by three maintenance doses of 1.4 microg/kg). To reach a steady-state body burden of TCDD the mice were allowed a 90-day recovery period before infection with CB3 virus. TCDD increased the infection-induced mortality rate, whereas in TCDD-exposed mice, heart lesions at day 7 after the virus inoculation (median value 0.67% of the tissue section area; interquartile range 0.28; not statistically significant) were one-third of that in non-exposed infected mice (2.07% of the tissue section area; interquartile range 3.06). The size of the inflammatory heart lesion correlated to the amount of virus (r(s) = 0.829, P < 0.01) as well as to the calcium (Ca: r(s) = 0.725, P < 0.01) and the magnesium (Mg: r(s) = -0.615, P < 0.05) contents. In TCDD-exposed mice in situ hybridisation of viral RNA in the myocardium at day 7 showed a tendency to decreased amounts of virus, as well as a less pronounced increase in myocardial Ca content, both supporting a milder myocardial disease after TCDD exposure. No effect of TCDD exposure was seen on the zinc (Zn) or selenium (Se) levels in the myocardium. In conclusion, although TCDD seemed to have a limiting effect on viral replication and the development of the inflammatory lesion in the myocardium, mortality was increased by TCDD in this infection model. However, TCDD had no significant effects on the selected trace elements that could be of importance for the severity of the inflammatory lesion (Ca, Se), for the local host response activation (Zn) or for the development of myocardial disease complications (Mg). Accordingly, the increased mortality may be a result of an infection-induced increase in TCDD toxicity to vital organs other than the heart, and/or a TCDD-induced change in the tissue affinity and virulence of the virus, possibly causing involvement of other target organs in the infectious process and changed pathogenesis.

Antioxidants and viral infections: host immune response and viral pathogenicity.

Malnutrition has long been associated with increased susceptibility to infectious disease. The increase in severity from and susceptibility to infectious disease in malnourished hosts is thought to be the result of an impaired immune response. For example, malnutrition could influence the immune response by inducing a less effective ability to manage the challenge of an infectious disease. Work in our laboratory has demonstrated that not only is the host affected by the nutritional deficiency, but the invading pathogen is as well. Using a deficiency in selenium (Se) as a model system, mice deficient in Se were more susceptible to infection with coxsackievirus, as well as with influenza virus. Se-deficient mice develop myocarditis when infected with a normally benign strain of coxsackievirus. They also develop severe pneumonitis when infected with a mild strain of influenza virus. The immune system was altered in the Se-deficient animals, as was the viral pathogen itself. Sequencing of viral isolates recovered from Se-deficient mice demonstrated mutations in the viral genome of both coxsackievirus and influenza virus. These changes in the viral genome are associated with the increased pathogenesis of the virus. The antioxidant selenoenzyme, glutathione peroxidase-1, was found to be critically important, as glutathione peroxidase knockout mice developed myocarditis, similar to the Se-deficient mice, when infected with the benign strain of myocarditis. This work points to the importance of host nutrition in not only optimizing the host immune response, but also in preventing viral mutations which could increase the viral pathogenicity.

Micronutrients and host resistance to viral infection.

Previous work in our laboratory demonstrated that a virus could undergo rapid mutation in a host deficient in Se, leading to a normally avirulent virus acquiring virulence due to genome changes. Once these mutations occur, even a host with adequate Se-nutriture is susceptible to the newly virulent virus. What influence does the deficiency in Se have on the immune response of the host? Infection with myocarditic strains of coxsackievirus induces an inflammatory response in the cardiac tissue. It is this immune response that induces the heart damage, rather than direct viral effects on the heart tissue. Chemokines are chemo-attractant molecules that are secreted during an infection in order to attract immune cells to the site of the injury, and have been found to be important for the development of coxsackievirus-induced myocarditis. We found that a deficiency in Se influences the expression of mRNA for the chemokine monocyte chemo-attractant protein-1, which may have implications for the development of myocarditis in the Se-deficient host. Expression of mRNA for interferon-gamma was also greatly decreased in the Se-deficient animal. Thus, a deficiency in Se can have profound effects on the host as well as on the virus itself. How the alteration of the immune response of the Se-deficient animal affects the development of the virulent genotype remains to be answered.

[Myocardial protection and immunoregulation of minor bupleurum decoction and its decomposed preparations on coxsackie B3m viral myocarditis in mice].

OBJECTIVE: To study the effect of Minor Bupleurum Decoction (MBD) and its decomposed preparations, decomposition-1 (DC-1) and decomposition-2 (DC-2) in myocardial protection and immunoregulation on coxsackie virus B3m induced myocarditis in mice. METHODS: Murine model of experimental myocarditis caused by coxsackie virus B3m was developed in Balb/c mice, and were treated by MBD, DC-1 and DC-2. Natural killer (NK) cell activity, T-lymphocyte subsets and histopathological change of myocardium were examined at various times after MBD, DC-1 and DC-2 were taken. RESULTS: (1) MBD and DC-2 could increase the NK cell activity significantly, and also regulate the T-lymphocyte subsets, while DC-1 did not have this kind of effect; (2) All MBD, DC-1 and DC-2 could protect myocardium obviously, the effect of MBD is better than those of its decomposed preparations. CONCLUSION: MBD and DC-2 had bi-directional regulation on NK cell activity and T-cell subsets, all the 3 groups could obviously protect myocardium.

Selenium and host defence towards viruses.

The association between viral disease and nutrition has long been thought to be due to effects on the host immune system. This theory suggests that when a host is malnourished, the immune system is compromised, and thus increased susceptibility to viral infection will occur. However, the virus itself may also be affected by the nutritional status of the host. We have demonstrated that a normally-benign strain of coxsackievirus B3 (CVB3/0) becomes virulent in either Se-deficient or vitamin E-deficient mice. Although the deficient animals are immunosuppressed, the virus itself is also altered. Six nucleotide changes were found in the virus that replicated in the deficient mice, and once these mutations occurred, even mice with normal nutrition became susceptible to disease. Thus, the nutritional status of the host was able to transform an avirulent virus into a virulent one due to genomic changes in the virus. We believe that a common mechanism of oxidative stress is the underlying cause of the genetic changes. Both vitamin E and Se act as antioxidants, and benign virus inoculated into GSH peroxidase (EC 1.11.1.9)-knockout mice will also convert to virulence due to genomic changes. Our work points to the importance of host nutrition during a viral disease, not only from the perspective of the host, but from the perspective of the viral pathogen as well.

[Effect of shen-dong-xin-bao oral liquid on IFN-induction and NK cell activity in CVB3m infected mice].

OBJECTIVE: Our aim was to investigate the effect of Shen-dong-xin-bao oral liquid on IFN-induction and NK cell activity in mice with coxsackie virus B3(CVB3m) infection in different infective stages. METHODS: The level of serum interferon (IFN) and the activity of natural killer (NK) cells in CVB3m induced myocarditis in mice were determined. Natural killer cell cytolytic activity was tested by MTT method and interferon titers by 50% microcytopathic effect assay. RESULTS: In the infected mice fed with 30 g/kg or 12 g/kg per day of Shen-dong-xin-bao oral administration for 10d and 20d, the mean titers of IFN were markedly higher than that in untreated infected group, P < 0.05. The NK cell activity in treated infected groups was also prominently higher than that in untreated infected group, especially on 20d, P < 0.05. CONCLUSION: This results demonstrate that administration of Shen-dong-xin-bao oral liquid possesses enhancement of antiviral immunocompetent action.

[Clinical study on Shuanghuanglian powder in treating children viral myocarditis].

OBJECTIVE: To study immune function of children viral myocarditis and to evaluate the clinical effect of Shuanghuanglian Powder (SHLP). METHODS: The authors determined serum COXB-IgM and the numbers of lymphocyte subsets CD3+, CD4+, CD8+, CD4+/CD8+ with viral myocarditis patients by ELISA and indirect immunofluorescent assay. Sixty-two cases were divided randomly into two groups. Thirty-two cases treated by conventional therapy with SHLP and the other 30 cases treated with conventional therapy alone were taken as control group. RESULTS: COXB-IgM was positive in 39 of 62 patients, which were significantly different with those of normal controls (P < 0.001). In addition, the level of CD4+ cells and the ratio of CD4+/CD8+ were decreased while CD8+ increased. After treatment with SHLP, the recovery of symptoms, signs and immune function in patients were better than that of controls. These changes were significantly different (P < 0.01). CONCLUSIONS: There were disturbance of immune regulatory function with children viral myocarditis patients and SHLP is an effective drug in treating children viral myocarditis.

Rapid genomic evolution of a non-virulent coxsackievirus B3 in selenium-deficient mice.

Keshan disease, an endemic cardiomyopathy in China, can be prevented with selenium (Se) supplementation. However, the seasonal and annual nature of the disease suggests that an infectious co-factor is required along with a deficiency in Se. Using a murine model of coxsackievirus B3 (CVB3)-induced myocarditis, Se-deficient mice were shown to be more susceptible to the cardiopathologic effects of the virus. In addition, a normal benign strain of CVB3 becomes virulent in Se-deficient mice. This change in virulence was shown to be due to point mutations in the viral genome. Although the mechanism of the viral mutation is not known, the oxidative stress status of the Se-deficient host may play a role, either by directly affecting the virus and/or affecting host immune defenses.

Increased virulence of coxsackievirus B3 in mice due to vitamin E or selenium deficiency.

Nutrition has long been known to affect the ability of the host to respond to infectious disease. Widespread famines are often accompanied by increased morbidity and mortality due to infectious diseases. The currently accepted view of the relationship between nutrition of the host and its susceptibility to infectious disease is one of a direct relationship with host immune status. That is, if the nutritional status of the host is poor-due to either single or multiple nutrient deficiencies-then the functioning of the host immune system is compromised. This impairment of the immune response will lead to an increased susceptibility to infectious disease. Clearly, the immune response has been shown to be weakened by inadequate nutrition in many model systems and in human studies. However, what about the effect of host nutrition on the pathogen itself? Our laboratory has shown, using a mouse model of coxsackievirus-induced myocarditis, that a host deficiency in either selenium or vitamin E leads to a change in viral phenotype, such that an avirulent strain of the virus becomes virulent and a virulent strain becomes more virulent. The change in phenotype was shown to be due to point mutations in the viral genome. Once the mutations occur, the phenotype change is stable and can now be expressed even in mice of normal nutriture. Our results suggest that nutrition can affect not only the host, but the pathogen as well, and demonstrate a new model of relating host nutritional effects to viral pathogenesis.

[The effect of chaihu qingxin yin on left cardiac function and T-cell subgroup in peripheral blood in children with viral myocarditis].

OBJECTIVE: To observe the effect of Caihu Qingxin Yin (CHQXY) in treating viral myocarditis. METHODS: CHQXY was used to treat 52 cases of acute viral myocarditis in children, compared with the routine method using energy mixture in 32 patients. RESULTS: (1) The total effective rate of 52 patients using CHQXY was 71.2% which was higher than that of the control group in 32 patients with 53.1%, Ridit analysis, P < 0.01. (2) Functional shortaxial shortening rate (FS) and ejecting fraction (EF) in CHQXY group were superior to those of the control group, P < 0.01. (3) CHQXY might modulate the immune function of T lymphocyte, enabled the CD3 and ratio of CD4/CD8 tended to normalize. CONCLUSION: CHQXY played an important role in the treatment of viral myocarditis with the mechanism of improving the left cardiac function and modulating celluar immune function.

[Therapeutic effect of yupingfeng san and shengmai yin on Coxsackie B viral myocarditis].

A "LDH release method" was used to determine NK cell activity in 30 cases of Coxsackie B viral myocarditis and contrasted with 20 normal volunteers. About 80% cases revealed NK cell activity deficiency. Among them, the NK activity of 24 cases (80%) was less than 14%; and 15 cases (50%) less than 10%. After Yupingfeng San and Shengmai Yin treatment for 2-3 months, their NK cell activity was elevated from 12.26 +/- 1.31% to 31.99 +/- 4.23% (P less than 0.001). At the same time, their clinical manifestations and EKG changes were improved or returned to normal.