Murine cytomegalovirus adrenalitis in athymic nude mice

Summary During studies of the pathogenesis of murine cytomegalovirus (MCMV) infection in athymic nude mice, we noted striking virus involvement of the adrenal glands. Because patients with the acquired immunodeficiency syndrome (AIDS) have recently been reported to have adrenal necrosis and evidence of infection of the adrenal gland with human cytomegalovirus (HCMV), we have further evaluated adrenal involvement during MCMV infection. Following virus inoculation, MCMV replicated to high titer in the adrenal glands of T-cell deficient, homozygous nude mice, but not heterozygous littermates with intact T-cell function. Concomitant with the high titers of virus, there appeared overt histological evidence of herpesvirus infection accompanied by patchy necrosis of adrenal cortical and medullary tissues. Acyclovir, which inhibits growth of MCMV, reduced virus replication in the adrenal gland. Similarly, virus replication was diminished in homozygous nude mice immunologically reconstituted by infusion of normal spleen cells three weeks prior to infection. Thus, in the absence of functioning T lymphocytes, MCMV can infect and replicate in adrenal tissues causing a progressive destructive adrenalitis.With 1 Figure     

Murine cytomegalovirus infection of cultured mouse embryos.

Isolated mouse whole embryos of 7.5 days' gestation were infected with murine cytomegalovirus (MCMV) and cultured in pure rat serum. Although the MCMV infection had little effect on the survival and development of the embryos during 3 days of cultivation, immunohistochemical analysis of their serial sections using monoclonal antibody showed MCMV-infected cells in various portions of the embryos. This monoclonal antibody, when tested with the use of infected cultured mouse fibroblasts, reacted with nuclear antigen within 2 hours after infection and also reacted with nuclear inclusions in the late phase of infection. The viral antigen-positive cells detected by the monoclonal antibody were present in almost all of the ectoplacental cone and the yolk sac and in about 82% of the embryos. In the embryos, antigen-positive cells were frequently observed in the epithelium of the digestive tracts, endothelial cells of the blood vessels, and the mesodermal cells. In some of the embryos, viral antigen-positive cells were clearly observed in a small percentage of the blood cells. These findings indicate that blood cells, in addition to cell migration during embryogenesis, may play an important role in transmission of infectious virus into the embryos. Mouse whole embryo culture infected with MCMV can provide a model for the study of cellular tropism related to congenital infection by cytomegalovirus.     

Protective effect of early serum from mice after cytomegalovirus infection.

Serum obtained from mice 3 to 5 days after cytomegalovirus infection contained complement-requiring neutralizing antibody, which, when passively transferred, protected mice from lethal infection with the homologous virus. The active substance was largely heat-stable 7s immunoglobulin.     

Neuron-specific activation of murine cytomegalovirus early gene e1 promoter in transgenic mice

The brain is the main target in congenital cytomegalovirus (CMV) infection and immunocompromised patients. No definite evidence that a CMV has special affinity for the central nervous system (CNS) has been published. Here, we generated transgenic mice with an e1 promoter/enhancer region connected to the reporter gene lacZ. Surprisingly, expression of the transgene was completely restricted to the CNS in all lines of transgenic mice. The transgene was expressed in subpopulation of neurons in the cerebral cortex, hippocampus, diencephalon, brainstem, cerebellum, and spinal cord in all of the lines. Non-neuronal cells in the CNS were negative for transgene expression. Activation of the transgene was first observed in neurons of mesencephalon in late gestation, and then the number of positive neurons increased in various parts of the brain as development proceeded. Upon infection of the transgenic mouse brains with MCMV, the location of the activated neurons became more extensive, and the number of such neurons increased. These results suggest that there are host factor(s) that directly activate the MCMV early gene promoter in neurons. This neuron-specific activation may be associated with persistent infection in the brain and may be responsible for the neuronal dysfunction and neuronal cell loss caused by CMV infection.     

MCP-1 in Alzheimer's disease patients: A-2518G polymorphism and serum levels

MCP-1 levels are increased in CSF of patients with Alzheimer's disease (AD) compared with controls, suggesting a role in the development of dementia. Recently, a biallelic A/G polymorphism in the MCP-1 promoter at position -2518 has been found, influencing the level of MCP-1 expression in response to an inflammatory stimulus. The distribution of the A-2518G SNP was determined in 269 AD patients and in 203 healthy age matched controls, showing no differences between the two groups. On the contrary, a significant increase of MCP-1 serum levels in AD patients carrying at least one G mutated allele was observed. Moreover, the highest peaks of MCP-1 serum levels were present in patients carrying two G alleles. Stratifying by ApoE genotype, gender or age at onset, no differences in both allele frequency and MCP-1 serum concentration were observed. The A-2518G polymorphism in MCP-1 gene does not seem to be a risk factor for the development of AD, but its presence correlates with higher levels of serum MCP-1, which can contribute to increase the inflammatory process occurring in AD.     

苦参素对HBsAg转基因小鼠血清Th1和Th2细胞因子水平的影响

目的　探讨苦参素对HBsAg转基因小鼠外周血Th1 Th2细胞因子水平的影响。方法　HBsAg转基因小鼠分成苦参素组和对照组 ,分别每天腹腔注射苦参素注射液 2 0 0mg kg 0 2ml和生理盐水 0 2ml,共 30d。处理前后 ,检测外周血清细胞因子水平。结果　对照组处理前后γ 干扰素(IFN γ)与白细胞介素 4 (IL 4 )水平差异无显著意义 ;苦参素组处理前后IFN γ分别为 (3 10 8± 3 172 )pg ml和 (11 0 5 9± 6 971)pg ml,IL 4分别为 (2 9 0 4 5± 13 2 35 )pg ml和 (13 0 2 4± 9 0 0 2 )pg ml(均P <0 0 0 1)。处理后对照组与苦参素组IL 2分别为 (1 0 70± 0 4 4 7)pg ml和 (5 5 37± 2 887)pg ml(P <0 0 0 0 1) ;IL 10分别为 (97 2 2 6± 73 30 6 )pg ml和 (33 6 0 7± 2 3 15 4 )pg ml(P <0 0 1)。结论　在苦参素作用后 ,HBsAg转基因小鼠体内的Th1型细胞因子明显升高 ,Th2型细胞因子明显降低。这将有助于研究苦参素临床治疗乙型肝炎的机制。     

Predicting carotid restenosis by comparison of plaque MCP-1 mRNA expression and serum levels

As cardiovascular pathology grows in numbers, research into the discovery of new chemokine biomarkers should not be neglected, as they seem to be paramount in atherosclerosis prevention and its early detection. Chemokines attract and activate leukocytes and are well recognized in the environment of inflammatory response. MCP-1 is a valuable chemokine whose potential to become a new crucial atherosclerosis marker is surely worth investigating. Since quantities of MCP-1 found in lesions are as low as immeasurable, we propose the use of an immunohistochemical method for the quantification of MCP-1 levels in atherosclerotic lesions. Additionally, serum levels of MCP-1 can be measured by commercially available immunoassays. Proposed MCP-1 concentration increase may explain the acceleration in lesion’s atherosclerosis progression as chemokine activation occurs once they bind to specific ligands. If proven, this hypothesis would indicate the need for further studies in order to objectively link the increased MCP-1 expression with carotid restenosis.     

Murine cytomegalovirus infection in the spleen and its relationship to immunosuppression.

An attempt was made to correlate murine cytomegalovirus-induced immuno-suppression with the presence of virus-infected cells in the spleen. For this purpose, SWR/J mice were infected with murine cytomegalovirus, and spleens were removed periodically and assayed for the presence of infectious centers in different cell populations and for their capacity to respond to mitogens. The maximal degree of immunosuppression correlated with the peak in adherent cell infectious centers. This was followed by a rapid rise in the number of cells per spleen (splenomegaly), a more gradual return to normal responsiveness to mitogens, and a rapid disappearance of infectious centers. These results add more support to the hypothesis that murine cytomegalovirus-induced immunosuppression is caused indirectly by infection of adherent spleen cells.     

Transforming growth factor-alpha deficiency reduces pulmonary fibrosis in transgenic mice

Despite evidence that implicates transforming growth factor-alpha (TGF-alpha) in the pathogenesis of acute lung injury, the contribution of TGF-alpha to the fibroproliferative response is unknown. To determine whether the development of pulmonary fibrosis depends on TGF-alpha, we induced lung injury with bleomycin in TGF-alpha null-mutation transgenic mice and wild-type mice. Lung hydroxyproline content was 1.3, 1.2, and 1.6 times greater in wild-genotype mice than in TGF-alpha-deficient animals at Days 10, 21, and 28, respectively, after a single intratracheal injection of bleomycin. At Days 7 and 10 after bleomycin treatment, lung total RNA content was 1.5 times greater in wild-genotype mice than in TGF-alpha-deficient animals. There was no significant difference between mice of the two genotypes in lung total DNA content or nuclear labeling indices after bleomycin administration. Wild-genotype mice had significantly higher lung fibrosis scores at Days 7 and 14 after bleomycin treatment than did TGF-alpha-deficient animals. There was no significant difference between TGF-alpha-deficient mice and wild-genotype mice in lung inflammation scores after bleomycin administration. To determine whether expression of other members of the epidermal growth factor (EGF) family is increased after bleomycin-induced injury, we measured lung EGF and heparin-binding- epidermal growth factor (HB-EGF) mRNA levels. Steady-state HB-EGF mRNA levels were 321% and 478% of control values in bleomycin-treated lungs at Days 7 and 10, respectively, but were not significantly different in TGF-alpha-deficient and in wild-genotype mice. EGF mRNA was not detected in normal or bleomycin-treated lungs of mice of either genotype. These results show that TGF-alpha contributes significantly to the pathogenesis of pulmonary fibrosis after bleomycin-induced injury, and that compensatory increases in other EGF family members do not occur in TGF-alpha-deficient mice.     

Elevated levels of GM-CSF and IL-1 in the serum, peritoneal and pleural cavities of GM-CSF transgenic mice.

Levels of granulocyte-macrophage colony-stimulating factor (GM-CSF) in the peritoneal and pleural cavity fluid of two lines of GM-CSF transgenic mice were abnormally high (up to 120,000 U/ml), often exceeded the elevated serum GM-CSF levels in these mice and correlated with the increased number of macrophages present. In the peritoneal fluid, the only significant elevations of IL-1 levels were seen in moribund male-line transgenic mice. In contrast, IL-1 levels in pleural cavity fluid of male-line transgenic mice were clearly higher than those in littermate control mice or female-line transgenic mice. In male-line transgenic mice, IL-1 levels in both peritoneal and pleural cavities correlated with local macrophage numbers. Endotoxin was detectable in the peritoneal cavity fluid from some mice of all types but did not correlate with elevated IL-1 levels. No correlation was observed between levels of GM-CSF or IL-1 in the peritoneal cavity and the development of fibrotic nodules in the peritoneal cavity or gut congestion, two lesions common in male-line GM-CSF transgenic mice. The data suggest that the elevated levels of IL-1 in GM-CSF transgenic mice may be the consequence of stimulation by GM-CSF of IL-1 production by the elevated numbers of macrophages in these mice.     

Murine cytomegalovirus gene expression during nonproductive infection in go-phase 3T3 cells

Murine 3T3 cells, maintained in the Go-phase by deprivation of serum, were infected with murine cytomegalovirus (MCMV) and examined for the synthesis of viral DNA, RNA, and proteins. No viral DNA replication could be detected, although the viral genome remained viable since infectious centers persisted. Viral RNA was analyzed by reassociation kinetics with ¹²⁵I-MCMV DNA. At early and late times after infection, the percentage of viral DNA transcribed amounted to 18% and 21%, respectively (comprising one abundance class), in contrast to 26% and 38%, respectively (two abundance classes), at corresponding times during productive infection in growing 3T3 cells. Five viral polypeptides were detected in the Go-phase cells, but these did not include structural polypeptides. When infected Go-phase cells were exposed to serum and fresh medium, viral DNA synthesis occurred, and progeny virions appeared subsequently. Thus this system may prove useful for analyzing a latent herpes infection in vitro.     

Expression and biological effects of high levels of serum IgE in epsilon heavy chain transgenic mice

We have generated and examined transgenic mice carrying a rearranged immunoglobulin transgene coding for the heavy chain of an IgE antibody. These mice produce the secreted form of the recombinant epsilon heavy chain. Serum IgE levels were increased at least 100-fold over control values. Transgenic epsilon mRNA was detected in spleen and thymus, not in liver and heart. Transgenic epsilon production in vitro was slightly up-regulated by T cells, but not affected by interleukin 4 in vitro or Nippostrongylus infestation in vivo. The B cell and T cell compartments and antigen-specific IgE, IgG1 and IgM responses as well as the increase in endogenous IgE after Nippostrongylus infestation in transgenic mice were normal. These data indicate that the presence of high levels of transgenic IgE did not induce class-specific suppressive mechanisms. Transgenic IgE bound to Fc epsilon receptor type I and Fc epsilon receptor type II and mediated histamine release from mast cells in vitro and an allergic skin reaction in vivo. It inhibited an ovalbumin-specific skin reaction in ovalbumin-immunized transgenic mice only during the initial phases of the immune response. This result has a bearing on the feasibility of immune therapy of allergic diseases with substances that block binding of IgE to its receptors.     

Ozone oxidative preconditioning reduces nitrite levels in blood serum in LPS: induced endotoxic shock in mice

Objective and design  Reactive oxygen species, and also reactive species of nitrogen such as nitric oxide, play an important role in the pathogenesis of peritonitis and septic shock. Ozone oxidative preconditioning (OOP) has shown protective effects in various experimental models of peritonitis in rats and endotoxic shock in mice. Currently, strong evidence is available that this protective effect of OOP is due to its action on the balance between endogenous antioxidants and pro-oxidants, which is favorable for anti-oxidant defense. The aim of this research was to elucidate whether or not OOP is able to reduce nitrite levels in blood serum of mice treated with lipopolysaccharide (LPS). We used an experimental model of endotoxic shock induced by LPS in mice in which the animals were pre-treated with ozone/oxygen mixture for 5 days (once daily), with injection of LPS 24 h thereafter to induce endotoxic shock. Results  Mice pretreated with OOP showed a significant decrease in nitrite levels with all three doses tested [0.2 mg/kg (50.91%), 0.4 mg/kg (47.3%) and 1.2 mg/kg (34.6%)]. Conclusions  Ozone oxidative preconditioning significantly reduced nitrite levels in blood serum of mice with endotoxic shock induced by LPS. We propose that OOP merits further testing in studies as a potential alternative treatment to reduce nitrite levels in patients with sepsis syndrome and septic shock.     

A kinetic study of SDF-1, VEGF and MCP-1 blood and tissue levels after aortic transplantation in mice

Vascular rejection is characterized by intimal proliferation and perivascular inflammation. We hypothesize that recipient stem cell therapy could prevent or ameliorate the development of the obliterative lesion. We studied the kinetic expression of three cytokines (SDF-1, MCP-1, VEGF) implicated in mobilization, homing and differentiation of progenitor cells during vascular aggression. An aortic allograft mouse model was used (BALBc donor-C57BL6/j recipient). Ten mice were sacrificed at Day 0, D1, D3, D6, D9, D12, and D20. Cytokine rates were measured in blood and in graft tissue by an ELISA technique. Results showed that in the allograft, SDF-1 and VEGF tissue levels were significantly increased at D12 as compared to the isograft (SDF-1: 22.16 ng/mg vs. 5.69 ng/mg, t = 3.38; VEGF: 28.3 pg/mg vs. 9.3 pg/mg, t = 3.06). In allografted and isografted groups, MCP-1 tissue levels were higher at D0 as compared to the other time points, without any difference between the two groups. These results prompt us to consider cell therapy at D0 and D12 in this mouse model of aortic graft.     

CVB3感染通过MCP-1介导病毒性心肌炎小鼠单个核细胞迁移

目的:研究B3型柯萨奇病毒(CVB3)感染与病毒性心肌炎(VMC)炎症细胞迁移的关系及机制。方法:采用差异贴壁法分离小鼠心肌细胞;趋化试验分析心肌细胞培养上清对VMC小鼠外周血单个核细胞(PMNC)的趋化性;实时定量RT PCR分析心肌细胞MCP 1的表达。结果:( 1)CVB3感染心肌细胞培养上清对VMC小鼠PMNC的趋化性明显增强。( 2 )CVB3感染2小时后MCP 1的表达开始升高,至6小时达到高峰,8小时下降;随着CVB3感染量的增加,MCP 1的表达明显升高。( 3)2 5 μg/ml抗MCP 1抗体处理后,CVB3感染心肌细胞培养上清对VMC小鼠PMNC的趋化性下降5 4 % (P <0 0 1) ;5 μg/ml抗MCP 1抗体处理后,趋化性下降的幅度与2 5 μg/ml抗MCP 1抗体处理的相比未见明显差异(P >0 0 5 )。结论:CVB3感染通过MCP 1介导VMC小鼠单个核细胞迁移,这可能是CVB3感染诱发心肌组织炎症细胞浸润的重要机制之一