Experimental murine model of disseminated Pseudallescheria infection.

Pseudallescheria boydii is found in soil and has a worldwide distribution. This fungus was initially identified as a pathogen targeting a variety of tissues. There are fragmentary data in the literature on the in vitro susceptibility of P. boydii to different antifungal compounds. P. boydii is highly refractory to antifungal treatments. In this study, a murine model of disseminated Pseudallescheria infection was developed to evaluate efficacy of different treatment regimens. A clinical strain of P. boydii was studied in normal and neutropenic outbred ICR mice. Several inocula were tested over a range from 1 x 10(3) to 5 x 10(6) cfu. Groups of eight mice were injected with a intravenous dose of one inoculum. Mortality correlated with the dose of the inoculum, and with immunosuppression. Quantitative cultures of various tissues showed initial dissemination of disease in immune competent mice. This was followed by, reduction of tissue burden, except in the brain. In contrast, disseminated infection persisted in most organs in immunosuppressed animals (p < 0.0001). This model should be appropriate for in vivo evaluation of antifungal chemotherapy.     

Clinical and experimental aspects of viral myocarditis.

Picornaviruses are frequently implicated as the etiological agents of acute myocarditis. This association is based historically on serological evidence of rising antibody titers to specific pathogens and more recently on identification of viral genomic material in endocardial biopsy specimens through in situ hybridization. Only rarely is infectious virus isolated from either the patient or the heart during periods of maximum myocardial inflammation and injury. Thus, despite a probable viral etiology, much interest centers on the role of the immune system in cardiac damage and the likelihood that the infection triggers an autoimmune response to heart-specific antigens. Heart-reactive antibodies and T cells are found in most myocarditis patients, and immunosuppressive therapy has proven beneficial in many, though not all, cases. Furthermore, murine models of coxsackievirus group B type 3-induced myocarditis also demonstrate that virus infection initiates autoimmunity and that these autoimmune effectors are predominately responsible for tissue injury. How virus-host interactions overcome presumed self-tolerance to heart antigens is discussed, and evidence supporting various theories of virus-initiated autoimmunity and disease pathogenesis are delineated.     

EAE小鼠模型的构建及其免疫学机制的探讨

目的 用髓鞘少突胶质细胞糖蛋白35-55(MOG35-55) 多肽免疫C57BL/6小鼠建立实验性自身免疫性脑脊髓炎(EAE)模型并初步探讨EAE发病的免疫学机制.方法 用MOG35-55抗原免疫C57BL/6小鼠,观察实验动物的症状及中枢神经系统的病理改变;应用MTT法测定EAE 小鼠脾脏T淋巴细胞活化增殖程度;应用ELISA技术测定EAE小鼠血清IFN-γ浓度和抗MOG 35-55抗体水平.结果 EAE组发病率为100%,HE染色观察到脑脊髓炎性细胞浸润,白质脱髓鞘等病理改变;EAE小鼠脾脏MOG35-55反应性T淋巴细胞增殖活化,血清IFN-γ浓度和抗MOG35-55抗体随病情的加重而升高.结论 用MOG35-55多肽成功诱导了C57BL/6小鼠EAE模型;并推断EAE的发生可能与MOG 35-55反应性T淋巴细胞的活化、抗MOG35-55抗体和IFN-γ升高有关.     

Insulin promotes T cell recovery in a murine model of autoimmune myocarditis

Glucose‐insulin‐potassium (GIK) is a useful adjunct to myocarditis. Besides its essential action in energy metabolism, insulin also exerts an anti‐inflammatory effect. This study investigated the effect of insulin on myocardial inflammation in experimental autoimmune myocarditis (EAM) in mice and its potential role in T cell regulation. Mice were divided randomly into a normal control group, a saline‐treated EAM group and an insulin‐treated EAM group. The histopathological changes of myocardium, α‐myosin heavy chain (MyHCα)_614–629 antigen‐specific autoantibody titre, the serum level of cardiac troponin I (cTnI), mitogen‐activated protein kinase (MAPK) family members' activity and content were measured. Furthermore, the phenotype of T lymphocyte subsets in splenocytes was analysed to evaluate the immune status of mice. Insulin reduced serum cTnI of EAM mice on days 14 and 21 (P < 0·05) after immunization, with no changes in blood glucose and autoantibody production. Western blot revealed that extracellular signal‐regulated protein kinase (ERK1/2) may be a determining factor in this process. Total ERK1/2 and phospho‐ERK1/2 (p‐ERK1/2) were both up‐regulated in insulin‐treated mice after immunization. We also found that insulin treatment promoted T cell recovery without changing the naive‐to‐memory T‐cell ratio; in particular, CD3⁺ T cells in insulin‐treated mice proliferated more vigorously than in control mice (P < 0·05). We report here for the first time that insulin alleviates myocarditis in the EAM model. These data show that insulin has a direct effect on T cell proliferation in EAM. It is possible that GIK or insulin may assist T cell recovery towards normal in myocarditis, especially for diabetic or hyperglycaemic patients.     

应用核酸分子杂交技术检测心肌炎组织中的肠道病毒RNA

用生物素标记ｐＣＢＩＩＩ／３５和ｐＣＢＩＩＩ／５１肠道病毒属特异性探针，对４５心肌炎和心肮病尸检或心肌活检心脏组织进行原位杂交，结果显示：１２例（２６．６％）存在肠道病毒ＲＮＡ。柯萨基Ｂ３病毒型特异性探针ｐＣＢＩＩＩ／２９进一步杂交表明，１２例经证实存在肠道病毒ＲＮＡ的心肌组织中５例（４１．７％）出现阳性杂交信号。阳性杂信号主要位于单个或多个心肌细胞的胞浆和心肌的间质组织，偶见竽心肌小血管内皮细胞     

Antigen-presentation capacity of dendritic cells is impaired in ongoing enterovirus myocarditis

Coxsackievirus B3 (CVB3)-infection is a frequent cause of acute myocarditis, which may result in chronic myocarditis and virus persistence. Investigation of the initial immune responses to CVB3 may shed light on the mechanisms that contribute to ongoing disease. DCs, as key professional APCs, were investigated in two MHC-matched hosts: while C57BL/6 mice are resistant to chronic CVB3-myocarditis, the A.BY/SnJ mouse strain exhibits susceptibility. DC maturation and activation were critically impaired in A.BY/SnJ mice, as reflected by the failure of DCs to induce co-stimulatory molecules and cytokine/chemokine responses. MHC class I-restricted antigen presentation via the cross-presentation pathway was also affected in DCs from A.BY/SnJ mice. DC maturation involves the accumulation of DC aggresome-like induced structures (DALISs) and the transient storage of defective ribosomal products (DRiPs). DCs from A.BY/SnJ mice showed permanent DALIS accumulation; the detection of poly-ubiquitinylated CVB3 proteins in these DALISs suggested a limitation in the MHC class I antigenic supply in this host. In conclusion, ongoing chronic disease in A.BY/SnJ mice due to a failure to clear the virus may be attributed to defects in DC maturation/activation and DC MHC class I antigen processing.     

Neurologic complications in children with enterovirus 71 infection.

BACKGROUND: Enterovirus 71 infection causes hand-foot-and-mouth disease in young children, which is characterized by several days of fever and vomiting, ulcerative lesions in the oral mucosa, and vesicles on the backs of the hands and feet. The initial illness resolves but is sometimes followed by aseptic meningitis, encephalomyelitis, or even acute flaccid paralysis similar to paralytic poliomyelitis. METHODS: We describe the neurologic complications associated with the enterovirus 71 epidemic that occurred in Taiwan in 1998. At three major hospitals we identified 41 children with culture-confirmed enterovirus 71 infection and acute neurologic manifestations. Magnetic resonance imaging (MRI) was performed in 4 patients with acute flaccid paralysis and 24 with rhombencephalitis. RESULTS: The mean age of the patients was 2.5 years (range, 3 months to 8.2 years). Twenty-eight patients had hand-foot-and-mouth disease (68 percent), and 6 had herpangina (15 percent). The other seven patients had no skin or mucosal lesions. Three neurologic syndromes were identified: aseptic meningitis (in 3 patients); brain-stem encephalitis, or rhombencephalitis (in 37); and acute flaccid paralysis (in 4), which followed rhombencephalitis in 3 patients. In 20 patients with rhombencephalitis, the syndrome was characterized by myoclonic jerks and tremor, ataxia, or both (grade I disease). Ten patients had myoclonus and cranial-nerve involvement (grade II disease). In seven patients the brain-stem infection produced transient myoclonus followed by the rapid onset of respiratory distress, cyanosis, poor peripheral perfusion, shock, coma, loss of the doll's eye reflex, and apnea (grade III disease); five of these patients died within 12 hours after admission. In 17 of the 24 patients with rhombencephalitis who underwent MRI, T2-weighted scans showed high-intensity lesions in the brain stem, most commonly in the pontine tegmentum. At follow-up, two of the patients with acute flaccid paralysis had residual limb weakness, and five of the patients with rhombencephalitis had persistent neurologic deficits, including myoclonus (in one child), cranial-nerve deficits (in two), and ventilator-dependent apnea (in two). CONCLUSIONS: In the 1998 enterovirus 71 epidemic in Taiwan, the chief neurologic complication was rhombencephalitis, which had a fatality rate of 14 percent. The most common initial symptoms were myoclonic jerks, and MRI usually showed evidence of brainstem involvement.     

Monoclonal anti-idiotypic antibodies regulate the expression of virus-induced murine myocarditis.

A monoclonal anti-idiotypic antibody (anti-Id), produced by electrofusion and designated anti-Id88, was able to modulate expression of murine autoimmune myocarditis mediated by coxsackievirus B3 (CVB3). The anti-Id was characterized as an immunoglobulin G2b species possessing kappa light chains and was able to reduce expression of inflammatory myocarditis in anti-Id-pretreated mice challenged with CVB3. Anti-Id88 was able to stimulate specific cell-mediated immunity against anti-Id88, as well as CVB3, and exerted a suppressive effect on the proliferation of mixed spleen cell populations from virus-exposed mice. Anti-Id stimulated an anti-anti-Id antibody 3 population able to bind antibody 2 F(ab')2 fragments or virus antigen in an indirect enzyme-linked immunosorbent assay. Western blot (immunoblot) analysis of anti-Id88 exhibited binding of syngeneic anti-Id antibody to idiotypes present on immunoglobulin G molecules from virus-immunized mice.     

Vaccination against Chlamydia genital infection utilizing the murine C. muridarum model

Chlamydia trachomatis genital infection is a worldwide public health problem, and considerable effort has been expended on developing an efficacious vaccine. The murine model of C. muridarum genital infection has been extremely useful for identification of protective immune responses and in vaccine development. Although a number of immunogenic antigens have been assessed for their ability to induce protection, the majority of studies have utilized the whole organism, the major outer membrane protein (MOMP), or the chlamydial protease-like activity factor (CPAF). These antigens, alone and in combination with a variety of immunostimulatory adjuvants, have induced various levels of protection against infectious challenge, ranging from minimal to nearly sterilizing immunity. Understanding of the mechanisms of natural infection-based immunity and advances in adjuvant biology have resulted in studies that are increasingly successful, but a vaccine licensed for use in humans has not yet been brought to fruition. Here we review immunity to chlamydial genital infection and vaccine development using the C. muridarum model.     

Efficacy of caspofungin and posaconazole in a murine model of disseminated Exophiala infection.

Disseminated phaeohyphomycosis is an uncommon infection affecting immunocompetent and immunocompromised individuals in which response to older antifungal agents has been variable. We compared the effect of six days of therapy with caspofungin, posaconazole, and amphotericin B in parallel studies of survival and fungal burden in an immunocompromised mouse model of Exophiala infection. Mice immunocompromised with cyclophosphamide were treated for 6 days starting one day after initiation of infection. Treatment regimens included amphotericin B, caspofungin, and posaconazole. In the survival studies, experimental animals were observed for 14 days. In the fungal burden tests the experimental animals were sacrificed 7 days after infection and brain and kidney burden determined. Treatment with any agent decreased mortality (P < 0.05), with 40%, 30%, and 80% observed survival of the animals treated with amphotericin B, caspofungin, and posaconazole, respectively. Amphotericin B and posaconazole treatment resulted in a decrease in fungal burden compared to untreated controls (P < 0.05). No reduction in fungal burden was noted in the caspofungin group. All three antifungals evaluated improved survival of immunocompromised mice in this otherwise fatal disseminated phaeohyphomycosis. Amphotericin B and posaconazole reduced fungal burden. Posaconazole and caspofungin appear to have potential for use in treatment of this rare infection.     

Effect of immunization on experimental Bacteroides gingivalis infection in a murine model.

BALB/c mice were immunized with an invasive (A7A1-28) or noninvasive (381) Bacteroides gingivalis strain, Bacteroides intermedius, or Ringer solution. All immunized mice were subsequently challenged with the invasive B. gingivalis strain and examined for septicemia or secondary spread of the infection or both. Mice immunized with the invasive B. gingivalis strain localized the infection to the challenge site. Mice immunized with the noninvasive B. gingivalis strain, B. intermedius, or Ringer solution developed spreading infections. These data suggest that immunization with an invasive B. gingivalis strain can alter the course of subsequent infections.     

Altered immunoregulation and autoimmune aspects of HIV infection: relevant murine models

After initial infection with human immunodeficiency virus 1 (HIV-1), patients may remain asymptomatic for years before the onset of acquired immune deficiency syndrome (AIDS). This non-aggressive or latent phase may be manifested by functional abnormalities of both T and B cells, even in the absence of critical reductions in lymphocyte numbers. At present, it is not clear whether the immune abnormalities in either the asymptomatic phase or in clinical AIDS are due solely to direct effects of HIV-1 or whether they also reflect host immunoregulatory mechanisms. In this article, by Charles Via, Herbert Morse and Gene Shearer, the immune abnormalities associated with early HIV-1 infection are compared with immune abnormalities found in three murine models of autoimmunity and immunodeficiency, and it is suggested that host mechanisms contribute to defective helper T (TH)-cell function early in the course of HIV-1 infection. Furthermore, two murine models appear relevant to the study of late HIV-1 infection and suggest a role for CD8+ T cells in the prevention of symptomatic AIDS.     

Prognostic implications of myoclonic jerk in children with enterovirus infection.

To determine the prognostic value of myoclonic jerk in children with enterovirus 71 (EV71) infection, a retrospective study was conducted on 665 enterovirus culture-confirmed patients admitted to Chang Gung Children's Hospital from January 2000 to September 2001. The mean age was 35.0 months +/- 32.2 months, ranging from 1 day to 15 years and 416 (62.6%) of them were male. Among these patients, 140 (21.1%) had EV71 isolated, and 150 (22.6%) had myoclonic jerk. Fifty one percent (72/140) of EV71 cases and only 15% (78/525) of non-EV71 cases had myoclonic jerk (p<0.001). The age of enterovirus patients with myoclonic jerk was younger than that of patients without myoclonic jerk (23.2 +/- 17.6 vs 38.4 +/- 34.6 months, p=0.005). The hospitalization and fever durations were significantly longer in the EV71 group than in the non-EV71 group (8.3 +/- 13 vs 4.2 +/- 2.7 days, p<0.001; 5.9 +/- 4.8 vs 4.2 +/- 3.0 days, p=0.009, respectively). Patients with myoclonic jerk also had higher percentages of severe illness, and neurologic sequelae (20% and 9%, respectively) than those without myoclonic jerk (5% and 1%, respectively) [p<0.001]. The positive predictive values of myoclonic jerk for EV71 infection, severe cases, and neurologic sequelae were 0.48, 0.20, and 0.09, respectively; the negative predictive values for severe cases and neurologic sequelae were 0.95 and 0.99, respectively. This study demonstrated that myoclonic jerk and EV71 infection are both independently associated with more severe disease and higher incidence of neurologic sequelae.     

Immunogenetic and immunologic aspects of gliosarcoma growth in rats

Growth of the chemically induced, transplantable rat brain tumor gliosarcoma 9L (GS-9L) is under immunogenetic control. Both susceptible and resistant rats produce an immune response to the tumor, but the response is qualitatively different in the two groups. The intraperitoneal administration of gliosarcoma-9L cells in resistant KGH rats causes the production of cytotoxic lymphocytes and macrophages, and in susceptible F344 rats suppressor lymphocytes are produced. After gliosarcoma-9L cells were administered to (KGH x F344)F1 and backcross rats, tumor susceptibility or resistance and the nature of the immune response correlated well with the histocompatibility type, indicating the parallel genetic control of both traits. However, a second gene or gene complex, not linked to the major histocompatibility complex, may participate in the regulation of tumor growth.