The effects of protein malnutrition on the pathogenesis of murine cytomegalovirus disease.

BALB/c and CBA mice maintained on low (4%) or normal (18%) protein diets for 2 weeks after weaning were infected with a sublethal dose of murine cytomegalovirus, adjusted in proportion to body weight. Viral replication, histopathological changes and humoral responses to the virus were compared between the dietary groups 2-42 days post infection (p.i.). Higher numbers of viral antigen-positive cells and/or more prominent tissue necrosis were noted in the livers, spleens, hearts, adrenal glands, kidneys and bone marrows of infected protein-deficient mice. These mice also showed a delayed onset of leucocytic exudation in their livers and salivary glands, relative to infected mice on the normal diet. Second peaks of viral replication were detected by plaque assays in livers and spleens from protein-deficient mice and in livers from normal mice 12-18 days p.i., but few antigen-positive cells and no tissue necrosis were observed. Virus also persisted at higher titres in the salivary glands from protein-deficient mice. Although cellular immunity may be defective in these mice, humoral IgG and IgM responses to the virus were not inhibited. The influence of genetic factors on the pathogenesis of murine cytomegalovirus disease in protein-deficient mice is discussed.     

IL-17 参与巨细胞病毒肝炎致病机制的研究

目的:在整体水平研究促炎细胞因子IL-17 在巨细胞病毒肝炎发病机制中的作用。方法:首先建立MCMV 全身播散性感染模型,设立正常对照组、MCMV 感染对照组、IL-17 阻断组和同型抗体对照组。在实验第7 天处死小鼠,Western blot 检测各组肝脏组织中IL-17 蛋白表达水平,病理评估各组肝组织损伤程度;罗氏生化分析仪检测小鼠血清ALT 水平;双抗体夹心ELISA 法检测血清中IL-17 水平; RT-PCR 检测肝脏组织内IL-17R、IFN-酌和IL-10 mRNA 的表达。结果:与MCMV 感染对照组及同型抗体对照组相比较,IL-17 抗体阻断肝脏组织IL-17 表达明显下降(P<0.05),病理损伤程度明显减轻,ALT 水平显著降低[ (146±15)vs (102±11)vs (37±12),P<0.05];血清中IL-17 水平降低[(719.76±6.06)vs (722.1±4.62) vs(707.53±8.58),P<0.05];IFN-γ[ (0.56±0.06)vs (0.55±0.13)vs (0.96±0.2),P<0.05] 与IL-10 mRNA[ (0.55±0.073)vs(0.51±0.07)vs(0.903±0.18),P<0.05]的表达明显增加,而IL-17R mRNA 表达差异无显著统计学意义[(0.81±0.16)vs(0.89±0.38)vs (0.870.23),P>0.05]。结论:促炎因子IL-17 高表达参与了巨细胞病毒肝炎的免疫损伤过程,阻断IL-17 有助于改善肝功能,减轻肝组织病理损伤。     

Models of vertical cytomegalovirus (CMV) transmission and pathogenesis

Despite the considerable clinical impact of congenital human cytomegalovirus (HCMV) infection, the mechanisms of maternal–fetal transmission and the resultant placental and fetal damage are largely unknown. Here, we discuss animal models for the evaluation of CMV vaccines and virus-induced pathology and particularly explore surrogate human models for HCMV transmission and pathogenesis in the maternal–fetal interface. Studies in floating and anchoring placental villi and more recently, ex vivo modeling of HCMV infection in integral human decidual tissues, provide unique insights into patterns of viral tropism, spread, and injury, defining the outcome of congenital infection, and the effect of potential antiviral interventions.     

巨细胞病毒感染在2型糖尿病发病中作用的研究

目的从定量水平上深入研究人类巨细胞病毒(HCMV)感染在2型糖尿病发病中的作用。方法采用定量PCR技术测量29例2型糖尿病患者和23例对照组血清中HCMV DNA含量,并与外周血T细胞亚群、血糖(BG)、胰岛素(Ins)和C肽(C-P)水平进行分析。结果 2型糖尿病患者HCMV DNA含量[(1.81±1.67)×108拷贝/ml]明显高于对照组[(5.50±4.30)×107拷贝/ml]。HCMVDNA阳性患者CD8百分率(29.53％±2.00％)显著高于对照组(27.13％±4.12％),CD4/CD8比值(1.24±0.05)显著低于对照组(1.41±0.10)。HCMV DNA阳性患者与阴性患者比较,空腹C-P明显降低,而BG和Ins差异无显著意义。结论2型糖尿病患者HCMV感染的活化,可影响细胞免疫,在2型糖尿病发病中的作用值得进一步研究。     

Role of CD4+ (helper) T cells in the pathogenesis of murine cytomegalovirus myocarditis.

Murine cytomegalovirus causes diffuse myocardial lesions in immunologically intact young adult male BALB/cBy mice. The cardiac changes develop in and around the small penetrating blood vessels of the heart where perivascular and interstitial infiltrates of macrophages and lymphocytes accumulate. Focal lesions of the coronary vessels and the endocardium also appear. When infected mice are depleted of CD4+ T lymphocytes, myocardial lesions fail to develop even though virus replication in the heart is enhanced. Contrary wise, when CD4+ cells are adoptively transferred into infected, thymectomized, irradiated, bone marrow-repleted mice, focal perivascular necrotizing lesions of the heart develop. Depletion of CD8+ T lymphocytes fails to influence virus replication and the development of cardiac lesions. Endothelial and endocardial cells appear to be major sites of virus replication in the heart. Delayed hypersensitivity is hypothesized to be the mechanism of cardiac injury in this model system.     

Treg/Th17平衡在巨细胞病毒感染发病机制中的作用

目的:研究调节性T细胞(Treg/Th17)细胞失衡在巨细胞病毒感染(CMV)免疫调节机制中的作用。方法:将CMV感染患儿按诊断标准分为激活感染组与潜伏感染组,同时设立正常对照组,采用流式细胞术(FCM)分析各组外周血Treg、Th17的百分比,并计算Treg/Th17比值;同时采用ELISA和RT-PCR法检测Treg主要相关因子(IL-10、Foxp3)和Th17主要相关因子(TGF-β、IL-17、IL-6、IL-23及ROR-γt)表达水平。结果:与对照组比较,CMV感染后Treg细胞百分率降低,Th17细胞升高,致Treg/Th17比值下降(P<0.05);CMV感染后两组间比较,激活感染组Treg/Th17比值和Treg主要相关因子表达水平下降更明显,而Th17主要相关因子表达水平显著上调,差异均有统计学意义(P<0.05)。结论:Treg/Th17平衡参与了CMV感染发病免疫机制,并可能与病毒潜伏-激活状态相关。     

Studies of the pathogenesis of wild-type virus and six temperature-sensitive mutants of mouse cytomegalovirus

A comparison of six temperature-sensitive (ts) mutants with the parental wild-type (wt) virus showed that, when 1-week-old BALB/c mice were inoculated intraperitoneally with 300 pfu of mouse passaged virus, the viruses could be broadly categorized into two groups. Two viruses (wt and tsm6) were lethal at this dose (10 and 2 LD₅₀ respectively); animals died within 4–6 days of inoculation and the virus became generalized infecting heart, lung, liver, spleen, kidney, and salivary glands to high titre (>4.3 log₁₀ pfu/ g). In contrast, for viruses (tsm1,tsm3, and tsm4) not lethal at this dose (300 pfu = 0.1 to 0.25 LD₅₀), viral replication was poor (<3.4 log₁₀ pfu/g) except in the salivary glands (5.6 to 7.5 log₁₀ pfu/g). Mutant tsm5 failed to replicate in any tissue while mutant tsm2, lethal at this dose (300 pfu = 1 LD₅₀), produced levels of virus similar to those found with tsm1, tsm3, and tsm4. Comparison of all viruses at sub-lethal doses (0.1 to 0.25 LD₅₀) did show minor differences in their replication in heart, and in levels of virus and duration of infection in kidney and salivary glands. More marked differences were evident between the viruses in their ability to be reactivated from the latent state during immunosuppression. Wild-type virus was most easily reactivated in that 67% of animals exhibited virus in salivary glands, heart, lung, spleen, and kidney. Mutants tsm1, tsm2, tsm3 and tsm6 could be reactivated but from fewer animals (33%, 33%, 18%, and 38% respectively) and fewer tissues. Mutants tsm4 and tsm5 could not be reactivated. Differences in the ability of the viruses to replicate in the lungs and to cause penumonitis in intranasally-inoculated immunosuppressed mice were also seen. Although immunosuppression was necessary for the induction of severe pneumonitis, differences in severity of pneumonitis resulted from differences in the ability of the mutants to replicate in the lung in vivo. These different mutants should prove useful for examining the viral and host factors involved in CMV-induced pneumonitis, and for examining mechanisms involved in latency and reactivation. © 1994 Wiley-Liss, Inc.     

Comparison of guinea pig cytomegalovirus and guinea pig herpes-like virus: pathogenesis and persistence in experimentally infected animals.

The pathogenesis of guinea pig cytomegalovirus (GPCMV) and guinea pig herpes-like virus (GPHLV) in guinea pigs was compared. Animals were inoculated with the two viruses by different routes and sacrificed after varying periods of time. GPCMV was consistently isolated from salivary gland 2 weeks postinoculation and thereafter following intraperitoneal or subcutaneous incoulaton. Virus was less frequently found in other tissues including blood, spleen, and kidney. Intranuclear inclusions were seen in tissue sections of salivary gland after inoculation with GPCMV- infected tissue suspension, but were only rarely found after inoculation with tissue culture virus. In GPHLV-infected guinea pigs, consistent latent infection of leukocytes and other tissues was detected by cocultivation techniques. Intranuclear inclusions were not found in the spleen, salivary gland, or other infected tissues after GPHLV infection with either tissue culture virus or infected tissue suspension. Guinea pigs inoculated with GPCMV produced high titers of specific neutralizing antibody to the homologous virus; those inoculated with GPHLV developed long-term viremia accompanied by minimal neutralizing antibody levels to the virus.     

Congenital cytomegalovirus infection.

The overall prevalence of congenital cytomegalovirus infection among the offspring of a highly immune young female population was 2.4 per cent (23 of 939). To ascertain whether the presence of anticytomegalovirus antibodies protects the developing fetus, we examined the offspring of 239 prospectively studied women. Despite substantial levels of preconceptional antibodies, intrauterine cytomegalovirus infection occured in seven of 208 (3.4 per cent) seroimmune women. Three neonates with congenital infection were born to 31 initially seronegative women. All the congenitally infected infants had subclinical involvement. Maternal humoral immunity may not protect the fetus against congenital cytomegalovirus infection. Neutralization kinetics and restriction enzyme analysis with endonucleases (EcoR-1 and HinD 111) demonstrated antigenic and genetic homology between viral strains isolated from two siblings consecutively infected in utero, indicating that repeat maternal infection with the same virus is transmissible to sequential products of conception.     

Therapeutic effect of acyclovir (ZoviraxTM) on the pathogenesis of chronic murine cytomegalovirus infection in the immunodeficient nude mouse.

The ability of acyclovir (ZoviraxTM) to influence the outcome of chronic cytomegalovirus infection in the nude mouse has been studied over a period of 3 weeks. Nude mice infected with a low dose of murine cytomegalovirus develop a chronic progressive disease which is characterized by typical lesions in the lung, the liver, salivary glands and many other organs. After 18-21 days most nude mice die of pneumonia and hepatitis. When acyclovir (ZoviraxTM) was administered s.c. twice daily, starting 1 day after the infectious dose of virus, a marked improvement was noted. No nude mice given the drug died in the 21-day period and the number of lesions to the lung, liver and salivary glands was reduced quantitatively by a highly significant amount.     

Defective virions of human cytomegalovirus.

Passage of human cytomegalovirus at high multiplicity of infection generated defective virus particles which banded in CsCI at a lower buoyant density than standard virus. The DNA from defective virions banded at a lower buoyant density in CsCl than standard DNA and sedimented in sucrose gradients similar to standard DNA. Contour length measurements of DNA from defective virions revealed various classes of DNAs ranging in molecular weight from 40 to 120 x 10⁶; this was in contrast to standard DNA with a molecular weight of 150 x 10⁶.     

Vertical transmission of murine cytomegalovirus.

Congenital abnormalities induced by murine cytomegalovirus have previously been suggested to be an indirect effect of maternal illness as no infectious virus has been isolated from the foetus. However, in this article we report that latent virus detectable by immunofluorescence and in situ hybridization, may frequently be present in foetal tissues.     

Human cytomegalovirus infection: diagnostic potential of recombinant antigens for cytomegalovirus antibody detection.

Recombinant antigen-based enzyme immunoassays (EIAs) for the detection of human cytomegalovirus (HCMV) specific antibody are believed to yield a higher sensitivity and specificity than virus lysate EIAs. The aim of the present study was to evaluate the accuracy of newly established HCMV assays (Copalis CMV Multiplex, Sorin; Cobas Core CMV IgG and IgM EIAs, Roche Diagnostics; Anti-HCMV recombinant IgG, gB-IgG, IgM and IgA, Biotest; and ETI-CYTOK-G PLUS and M reverse PLUS, Sorin) based on recombinant antigens and/or virus lysate for laboratory diagnosis of HCMV infection. For the assessment of sensitivity, follow-up samples from patients suffering from active HCMV infection were tested. Testing a large number of potentially interfering samples challenged the specificity of the assays. There was no statistically significant difference in the performance of HCMV IgG assays. The results were more heterogeneous for the detection of serological markers of active infection (HCMV IgM, HCMV IgA and anti-CM2). The sensitivities of the different assays ranged between 40.5 and 71.4%. A variable number (17.8-1.7%) of false-positive results were obtained among potentially interfering serum samples. Two of the recombinant antigen based assays showed a high degree of interference with EBV VCA-IgM-positive sera. The best performance was achieved with ETI-CYTOK-M reverse PLUS since it combined the highest sensitivity with specificity. Commercially available assays based on recombinant antigens showed, overall, a poorer performance than the virus lysate EIA.     

The pathogenesis of osteoarthrosis.

Recent investigations on protease inhibitors in articular cartilage have provided new insights into the possible initial lesions of osteoarthrosis. A hypothesis has been formulated based upon an impaired ability of chondrocytes to synthesize protease inhibitors, which leads to loss of matrix integrity and vascular invasion from subchondral bone and the joint margins.     

The pathogenesis of atherosclerosis.

The pathogenesis of atherosclerosis is hypothesized to occur as a response to various forms of injury to the lining arterial endothelial cells. The resulting endothelial alterations could potentially lead to interactions between platelets in the circulation and the underlying subendothelial connective tissue or with the altered endothelial cells themselves. Such interactions provide an opportunity for platelet degranulation and release of a platelet-derived growth factor. This factor has been shown in cell culture to be an extremely potent mitogen and will induce DNA synthesis and cell multiplication of a number of cells including smooth muscle cells, fibroblasts, and other mesenchymally derived cells. Chronic endothelial injury and repeated interactions between platelet-derived mitogens, plasma components, and the underlying arterial smooth muslce cells would promote the progression of the intimal proliferative lesions of atherosclerosis that lead to the clinical sequelae associated with this disease process.