Innate immunity is on the frontline of fight against pathogenic microorganism invasion .As a DNA sensor, absent in melanoma 2 (AIM2) is an important member of innate immune system.It can recognize dsDNA of pathogenic microbes to form AIM 2 inflammasomes , which facilitates defending and clearing the invasion of pathogens by activating caspase-1 dependent pyroptosis and the mature of IL-18 and IL-1β.AIM2 inflammasomes play an important part in responding to Listeria monocytogenes, Francisella tularensis, Streptococcus pneumoniae, Mycobacterium tuberculosis, Aspergillus fumigatus, vaccinia virus , murine cytomegalovirus , and hepatitis B virus infections .This paper introduces the components of AIM 2 inflammasomes and summarizes its function in defending the invasion of pathogenic microorganisms .

Objective To establish the murine congenital infection model by MCMV and observe the pathological changes and infection status of brain tissue.Methods After anesthesia,mice who were pregnant 11-13.5 days (E11-13.5 d) were intra-amniotic injected one uterus by one with virus (MCMV K181 suspension,1 μl,1×103 PFU).The control group of the same period was intra-anmiotic injected with culture medium DMEM (1 μl).Carefully reset the uteruses and close the abdomen.After 5 days of separated feeding,kill the pregnant mice,take the fetus out of the uterus,anesthetize and kill them.Make frozen sections of these fetal brains.Some sections were stained using conventional HE method,to observe the pathological changes under the light microscope.Detect MCMV early antigen in the brain tissue by immunohistochemistry staining and immunofluorescence assay.Results The survival rates of the infected group were 71.9％.Compared with the control group,intra-amniotic inoculation of MCMV does not affect the rate of fetal survival,fetal absorption,fetal death and the average weight of the heads,but decrease their average weight of the bodies.The pathological changes are found in the brain tissue of the mouse in the infection group.Through enzyme immunohistochemistry assay,there are many MCMV infected cells in brain-ventricular zone,brain subependymal zone,cerebral cortex and hippocampus area in the infection group.Similar findings were observed by immunofluorescence method.Conclusion By intra-amniotic injection of MCMV suspension,murine model of MCMV congenital infection can be successfully established.This model could be used to study the mechanisms of encephalodysplasia caused by congenital CMV infection in vivo.

Objective To explore the correlation between the expression of IL-17A and the degree of spleen damage in acute mouse cytomegalovirus(MCMV) disseminated infection in vivo and to understand the mechanism about how IL-17A involved in the pathological damage of the spleen in MCMV infection.Methods An acute disseminated MCMV infection model was established in mice.BALB/c mice were randomly divided into two groups.Mice in group one were infected with MCMV Smith to establish disseminated infection.Mice in another group were sham-infected control.Three mice from each group were randomly chosen to be sacrificed on days 3,7,14 and 28 after the infection.Viral titers in spleen tissues were determined using a standard plaque assay.The expression of IL-17A mRNA and MCMV mRNA in the splenocytes were measured by RT-PCR.The expression of IL-17A in spleen tissues was observed by immunohistochemical staining.The pathology of the infected mice was assessed by histological examination of H&E stained spleen sections.Results Viral titers and MCMV mRNA in the spleen peaked on day 3,but quickly diminished on day 7.Virus was no longer detectable in the spleen on day 14 after the infection.The expression of IL-17A mRNA was significantly increased during the acute infection and reached the highest level on day 14,then decreased on day 28.It is significantly higher than that of the mock infection group.Immunohistochemistry assay also indicated that the expression of IL-17A in spleen tissue gradually increased to climax on day 14,then decreased on day 28.Accordingly,the pathological damages of spleen tissue in the infected mice deteriorated until day 14,then showed signs of recovery on day 28.The most severe pathological injury of spleen tissue and the highest expression of IL-17A appeared in the same period of time.Conclusion Our results showed a close correlation between IL-17A and the pathological damage in spleen.Thus,IL-17A may contribute to the spleen pathological damage during the acute disseminated MCMV infection.

ObjectiveTo observe the changes of AIM2 ( absent in melanoma 2) inflammasome during early murine cytomegalovirus (MCMV) infection.MethodsBALB/c mice were randomly divided into two groups.One was infected with MCMV Smith for establishing disseminated infection,the other was sham-inoculated control.On days 1,3,5 and 7 of the experiment,three mice of each group were randomly chosen to be killed separately.The expression of AIM2,ASC and caspase-1 in splenic macrophages was detected by Western blot,the levels of IL-1β and IL-18 in sera were measured by double antibody sandwich ELISA,and the viral titers in salivary gland tissues were quantified by a standard plaque assay.Results The MCMV titers in salivary gland tissues were gradually increased in MCMV-infected mice on days 3,5 and 7,while the expressions of AIM2 in macrophages were began to increase on day 1 and significantly increased and reached the highest level on day 3 but gradually decreased afterwards.The relative intensity of AIM2 on day 3 differed significantly between the MCMV-infected mice and the controls (1.121±0.243 vs 0.240±0.046,P＜0.01,t test),as did ASC ( 1.318±0.333 vs 0.248±0.090,P＜0.01 ) and caspase-1 ( 1.085±0.243 vs 0.247±0.064,P＜0.01 ).Meanwhile,the levels of IL-1β and IL-18 in MCMV-infected mice were (112.72±5.20) pg/ml and (42.74±4.23) pg/ml,and the levels were significantly higher (P＜0.01 ) than those in controls [ (47.86±4.35) pg/ml and (22.60±2.82) pg/ml].ConclusionThese results demonstrate that AIM2 inflammasome is activated in macrophages during early MCMV infection and could be as a therapeutic target for CMV-induced diseases.

Objective To investigate the nature of Th17 cells in murine cytomegalovirus(MCMV)infection during the acute stage,we characterized the frequency of IL-17A-producing CD4 T cells and the level of Th17 cytokines,IL-17A,in MCMV-infected mice.Methods BALB/c mice were randomly divided into two groups.One was infected with MCMV Smith for establishing disseminative infection; the other was sham-inoculated control.On day 3,7,14 and 28 of the experiment,three mice of each group were randomly chosen to be killed separately.Real-time PCR was used to detect MCMV loads in organs of MCMV-infected mice,the pathology of spleen was observed by HE staining.The frequency of CD4+IL-17A+ T cells in total splenocytes of mice was detected by flow cytometry.The level of IL-17A in culture supernatants of splenocytes was measured by double antibody sandwich ELISA.Results MCMV loads in salivary gland reached the peak on day 14 after MCMV infection,the most severe spleen injury was also shown on day 14,the frequencies of CD4+IL-17A+ T cells in total splenocytes increased significantly( all P＜0.01 ) in MCMV-infected mice than those in controls,and reached the peak on day 14 ( 1.14％ ±0.09％ vs 0.19％ ±0.04％,t =17.551,P=0.000).The levels of MCMV-specific IL-17A in culture supernatants were increased dramatically in MCMV-infected mice than those in controls on day 14 [ (81.98± 12.37) pg/ml vs (44.96±8.44)pg/ml,t=4.281,P=0.006].In MCMV-infected mice,correlation was positive between the levels of MCMV-specific IL-17A in culture supernatants and MCMV loads in salivary gland tissues (r=0.54,P＜0.05 ),the levels of IL-17 A in culture supernatants were higher in more severe spleen injury.Conclusion Thl7 cells and IL-17A were involved in the immunity response during acute MCMV infection.They may correlate with the persistence of MCMV and the pathology of spleen in infected mice.

Objectives To investigate the effects of lipoxin receptor agonist BML-111 on IFN-βand IE86 mRNA expression of macrophages infected by human cytomegalovirus (HCMV). Methods Macrophages were infected with HCMV (MOI=0.5), and the cultured cells were randomly divided into control group, HCMV group, HCMV+BML-111 group, and HCMV+MP group. The cells were collected at 0,1,2,4,8 and 12 h after infection, and the levels of IFN-βand IE86 mRNA were tested by real-time PCR. Results Compared with HCMV group, the levels of IFN-βmRNA in HCMV+BML-111 group increased significantly (P < 0.05), while the levels of IFN-βmRNA in HCMV+MP group decreased significantly (P < 0.05); Compared with HCMV group, there were no significant differences of the levels of IE86 mRNA in HCMV+BML-111 group (P>0.05), while the levels of IE86 mRNA in HCMV+MP group increased significantly (P < 0.05). Conclusion BML-111 exerts antiviral activity by promoting the expression of IFN-βmRNA at the early stage of HCMV infection.

Murine cytomegalovirus (MCMV) IE3 protein is a multifunctional viral protein that interacts with several target proteins of both viral and host cellular origin. To investigate the biological function of IE3 in the pathogenesis of the brain disorders caused by CMV, a screening for host cellular proteins that could interact with IE3 was performed. By yeast two-hybrid screening, ankyrin repeats domain 17 (Ankrd17, also known as Gtar) was identified as a host factor that could interact with IE3. This interaction was verified by yeast two-hybrid assay and chemiluminescent co-immunoprecipitaion. Mapping analysis suggested that the 1-148 residues of IE3 were responsible for the interaction. These results suggested that the interaction between Ankrd17 and IE3 may play a key role in the pathogenesis of MCMV-associated disease.

Objective To investigate the influence of murine cytomegalovirus ( MCMV) infection on the expression of downstream differentiation related target genes of Wnt signaling pathway in neural stem cells (NSCs) in vitro and explore the molecular mechanism of fetal encephalodysplasia caused by CMV infection. Methods NSCs were separated from fetal BALB/c mouse and cultured in vitro. The NSCs infected by MCMV at a MOI (multiplicity of infection) of 5, 1 and 0.1, respectively, were cultured in differentiation medium. The dynamic expression of the downstream differentiation related target genes ( c-myc, cyclinD1, ngn-1 and ngn-2) of Wnt signal pathway in NSCs were measured by Western blot. Real-time RT-PCR was employed to measure the expression levels of the key differentiation genes ngn-1 in Wnt signal pathway of NSCs post infection. Results The protein levels of c-myc in the infected groups were significantly lower than that in the normal control at 0.5-5 d (P＜0.05) ; At 0. 5 d and 1 d post-infection (p. i. ) , the protein levels of cyclinDl in the infected groups were lower than that in the normal control (P＜0.05). At 2 d and 3 d p. i. , the cyclinD1 expression in the infected groups was higher than that in the control group (P ＜ 0. 05). However, at 4 d and 5 d p. i. , the cyclinD1 levels in the group of the MOI of 5 were lower than in other three groups (F＜0.05). The expression of ngn-1 protein in the infected groups was reduced importantly compared with normal control at 1 -5 d p. i. ( P ＜ 0.05 ). The expression of ngn-1 mRNA in the infected groups was lower than that in the control group at all time points (P ＜ 0. 05 ). The expression of ngn-2 protein decreased at first and then increased, which was opposite to the normal control. The peak of ngn-2 expression in groups of the MOT of 0.1 and 1 occurred later and were significantly lower than that in the normal control (P ＜0. 05). No distinct peak was seen in the group of the MOI of 5. At 1 d p. i. , the expression of ngn-2 of all infected groups was significantly lower than that in the normal control ( P ＜ 0. 05 ). At 2 d p. i. , the expression of in the group of the MOI of 5 was still lower (P ＜ 0.05). While at 3 d, 4 d and 5 d p. i. , the protein levels in all infected groups were higher than that in the normal control (P ＜ 0. 05). The protein expression of these genes increased following the increase of MOI. Conclusion MCMV inhibited the protein expression of c-myc and ngn-1 in differentiated NSCs, repressed the mRNA expression of ngn-1 and caused the perturbed expression of cyclinDl and ngn-2 in a MOI-dependent manner. These data suggest that inhibition of or interference with the protein expression of downstream differentiation related target genes of Wnt signaling pathway in NSCs by MCMV may be one of the important mechanisms, by which proliferation and differentiation of NSCs are inhibited and thus fetal brain is impaired after MCMV infection.

Objective To study the feature that murine cytomegalovirus(MCMV)infect macrophage strain RAW264.7 and the influence of virus infection on proliferation and apoptosis of RAW264.7 in vitro.Methods RAW was infected by MCMV Smith with multiplicity of infection(MOI)1,0.1 and 0.01,respectivelv.The cells and culture supernatant were collected at 6,12,24,36,48,72,96 and 120 h post-infection(P.i.).Cytopathic effect(CPE)was found with microscope.Virus particles and uhrastructural changes of RAW were observed by transmission electron microscope(TEM). Early antigen(EA)expression was assaved bv immunohistochemical method.The proliferation of MCMV was studied by plaque formation assay.The influence of virus infection on proliferation and apoptosis of RAW were measured by MTT method and flow cytometry.The mouse embryo fibroblast(MEF)susceptible to MCMV infection was positive contro1.Results RAW was swollen and desquamated on 24-48 h P.i..The full-grown virus particles and swollen organelles in RAW were displayed with TEM.Preliminary positive expression of EA was demonstra ted from 6 h(MOI=1 and 0.1)to 12 h(MOI=0.01)P.i..Virus titer in RAw supernatant increased obviouslv on 24 h p.i.and reached the peak on 96-120 h P.i..The proliferation of RAW could be obviously inhibited by MCMV on 72-120 h p.i..When infected by virus with MOI=0.1,necrotic cells of RAW increased on 72-120 h D.i.and the influence of MCMV infection on apoptosis of RAW was not obvious.Conclusion Macrophage strain RAW264.7 is susceptible to MCMV,and it emerges faster cytolytic and productive infection than MEF.MCMV can inhibit the proliferation of RAW but not influence the apoptosis of it.These results can provide a practical experimental model for studying immunological pathogenic mechanism of cytomegalovirus in vitro.

BACKGROUND:The anti-inflammation and protective effects of lipoxin have been verified in several immunity-related disease models. Preliminary studies of our research group have shown that, lipoxin receptor agonist BML-111 has negative regulation effects on the human cytomegalovirus (HCMV)-induced immunological injury. However, the effect of BML-111 on the HCMV replication remains unclear.
OBJECTIVE:To observe the influence of lipoxin receptor agonist BML-111 on HCMV replication and proliferation in THP-1 macrophages and human embryonic lung fibroblasts.
METHODS:THP-1 macrophages were infected by HCMV AD169 strain, and were divided into three groups:mock infection, HCMV infection, HCMV+BML-111. The final concentration of BML-111 was 100 nmol/L. cells in each group were col ected at 0, 1, 2, 4, 12, 36, 48 hours, the mRNA levels of IE86 and pp65 in the THP-1 macrophages were tested by RT-PCR method. Human embryonic lung fibroblasts were infected with HCMV (MOI=0.1), and were divided into two groups:HCMV infection and HCMV+BML-111. The patho-morphous changes of human embryonic lung fibroblasts were observed under light microscope, and the cellnumber was measured. The infective virus titer changes in human embryonic lung fibroblasts were examined by plaque assay.
RESULTS AND CONCLUSION:After the macrophages were infected by HCMV, compared with the mock infection group, the mRNA levels of IE86 and pp65 in the HCMV group and HCMV+BML-111 group were increased significantly;compared with the HCMV infection group, the mRNA levels of IE86 and pp65 in the HCMV+BML-111 group were increased significantly in the early stage (within 4 hours) after infection, but the pp65 mRNA levels were decreased significantly in the medium and late stages (24-72 hours) after infection. After human embryonic lung fibroblasts were infected by HCMV, the degree of the patho-morphous in the HCMV+BML-111 group reached 100%2 days earlier than the of HCMV infection group. The infective virus titer reached the peak 2 days earlier than the HCMV infection group, but no significant difference was found between the two groups. BML-111 accelerates the replication of HCMV in the early stage of infection, but inhibits the expression of pp65 gene in the late stage. BML-111 has no impact on the proliferation of the infective HCMV titer in vitro.