Preliminary study on effects of serial passage on growth-related properties and virulence of Chlamydia muridarum / 中华微生物学和免疫学杂志

Objective:To analyze the changes in biological characteristics including infectivity, growth and pathogenicity of Chlamydia muridarum ( Cm) after serial passage in vitro in special conditions in order to provide reference for screening attenuated live vaccines and virulence-related genes. Methods:Wild-type Cm strain (G0) was cultured for several passages using conventional cell culture method under alternate unassisted and assisted culture conditions. Then, the 28th generation (G28) of Cm was selected and compared with the parental G0 strain in terms of centrifugation dependence, attaching ability, intracellular growth curve, plaque size and fallopian tube lesions after genital tract infection in a mouse model. Results:Compared with the parental G0 strain, the G28 strain showed significantly decreased dependence on centrifugation during cell infection ( P<0.05) and increased attachment capacity to cells ( P<0.05). No significant differences were observed in the growth curves 32 h after cell infection or in the plaque sizes between the parental G0 and G28 strains. In the in vivo virulence test, fallopian tube lesions were observed in 87.5% of G0-infected mice and 37.5% of G28-infected mice ( P<0.05). Conclusions:Compared with the parental G0 strain, the G28 strain showed significantly enhanced in vitro infection ability, but decreased in vivo pathogenicity, which brought hope for further identification of virulence genes, isolation of attenuated strains with single genotype and development of live attenuated Chlamydia vaccines.

IL-10 promotes Chlamydia muridarum infection in mice through inhibiting IFN-γand IL-2 expression / 中华微生物学和免疫学杂志

Objective To study the possible molecular mechanism of IL-10 in promoting Chlamydia muridarum infection in mice. Methods C57BL/6 wild-type and IL-10 gene knockout ( IL-10-/-) mice were infected with Chlamydia muridarum. Indirect immunofluorescence assay was used to detect the growth of Chlamydia muridarum in the intestinal and genital tracts. The severity of genital diseases was assessed by hydrosalpinx scoring. Expression of IFN-γand IL-2 in blood was measured by ELISA. Re-sults Compared with the wild-type group, Chlamydia clearance in the intestinal and genital tracts of IL-10-/- mice was significantly faster, and the expression of IFN-γ and IL-2 increased significantly. In addi-tion, wild-type mice showed more serious hydrosalpinx. Conclusions IL-10 delays Chlamydia trachomatis clearance and promotes Chlamydia infection through inhibiting the expression of IFN-γ and IL-2, which ag-gravates hydrosalpinx.

Establishment of experimental model for saphenous artery perforator flap in mini pig / 中华显微外科杂志

Objective To investigate the anatomy characteristics of saphenous artery(SA) and its perforator vessels in mini pig,and to provide a new perforator flap animal model.Methods Between May,2018 and August,2018,6 7-months-old mini pigs weight 25 kilograms were sacrificed by blooding under general anesthesia.The bilateral external iliac arteries were injected with a mixture of latex-lead oxide mixture and underwent CT-scanning to provide 3-dimensional reconstruction.The origin,diameter,courses and distribution of the SA and perforators of both hind limbs were observed.Results One of the hind limbs was abandoned due to the leakage of perfusion fluid.The other 11 hind limbs were available.The femoral artery passed through the medial femoral muscle and sartorius muscle in the middle of thigh,and run between the medial femoral muscle and gracilis muscle above the knee.Below the knee,it run on the surface of the medial leg muscles.A number of small branches were distributed in the tarsal joint and calcaneus at the medial malleolus,and there were abundant communicating branches with the posterior tibial artery.The average length of SA was (14.86±0.76) mm.The outer diameters of SA at initiative,medial tibial condyle and medial malleolus were(1.73±0.15) mm,(1.50±0.12) mm and (1.30±0.13) mm,respectively.There were a total of 79 perforators which were identified,with a mean of (7.09±1.16) perforators per hind limbs.And the average outer diameter was 0.10-0.78 (0.40±0.13) mm.Conclusion The SA constantly exist with good outer diameter.The number of perforator is abundant.SA can be used as a reliable animal model for studying and training of perforator flap.

Preliminary study on genital tract immune injury in mice induced by pORF5 plasmid protein of Chlamydia trachomatis / 中华微生物学和免疫学杂志

Objective To investigate the immune injury in genital tract of BALB/c mice induced by plasmid protein pORF5 of Chlamydia trachomatis and its possible mechanism.Methods GST(glutathione-S-transferases)-pORF5 fusion protein was expressed and digested with PreScission Protease to obtain the target protein without GST tag.After further purification and endotoxin removal,pORF5 protein was injected into the posterior fornix of BALB/c mice on day 1,3 and 6,while the control groups were injected with PBS or GST protein respectively,and then all the mice were sacrificed on day 7 to evaluate genital tract gross pathology and histopathological characterization.The levels of TNF-α,IL-1β and IL-6 in serum,splenocytes culture supernatant and vaginal douche were detected by ELISA.Results Mice in pORF5 group developed different degrees of swelling in isthmic portion and ampulla of uterine tube,connective tissue adhesion and hydrosalpinx in the genital tract tissues,while the PBS group and the GST group did not show any obvious change.The inflammatory score showed that the genital tract pathology in pORF5 group was much more severe than PBS and GST control groups (P＜0.O1).The levels of TNF-α,IL-1β and IL-6 in vaginal douche and splenocytes culture supernatants in pORF5 group were obviously higher than those of PBS and GST groups (P＜0.05).The levels of TNF-α and IL-1β in serum were also higher than those of GST and PBS groups (P＜0.01).Conclusion pORF5 plasmid protein could induce pathological immune response in the genital tract of BALB/c mice,which may be associated with the increase of the production of the inflammatory cytokines TNF-α,IL-1β and IL-6 in BALB/c mice.

Chlamydia trachomatis serovar D genital tract infected mice model: establishment and evaluation / 中华微生物学和免疫学杂志

ObjectiveTo construct a mouse model for studying pathophysiology and mechanism of human Chlamydia trachomatis genital infection.MethodsInnate immunity-deficient C3H/HeJ female mice were infected intravaginally with human C.trachomatis serovar D urogenital isolates for screening the highest violent clinical strain.The clinical strain UT0603 as well as standard strain D/UW-3/CX were then used to reinfect na(i)ve mice,the lower genital tract shedding were monitored by swabbing every 3-7 day over the entire infection period by culture.Some mice were sacrificed at early infection stage to detection of in site Chlamydia growth by immunofluorescence assay,then all the mice were sacrificed at later infection stage to evaluate upper genital tract gross pathology and histopathological characterization.ResuIts In the lower genital tract,Chlamydia shedding time course were significantly prolonged in clinical strain infected mice.Chlamydia not only growth in the lower genital tract,the live organism also ascending and growth in the upper genital tissue.The gross appearance under naked eyes and dilation and inflammation scores under microscope all showed that the genital tract pathology from the clinical strain infected mice were much more severe than standard strain infected control mice.Conclusion Together,all these results demonstrated that a mouse model for Chlamydia genital infection was constructed.

Preliminary study on biological characterization of Chlamydia trachomatis plasmid protein pORF5 / 中华微生物学和免疫学杂志

Objective To localize and characterize the plasmid protein pORF5 in the Chlamydia trachomatis(Ct) infected cells. Methods The open reading frame encoding for pORF5 protein from the Ct plasmid was amplified and cloned into the pGEX-6p vector. The recombinant plasmid pGEX-pORF5 was transformed into XL1-blue E. coli to express fusion protein with the glutathione-s-transferase (GST). After purified with Glutathione Sepharose 4B beads, the pORF5 fusion protein was used to immunize mice to make monoclonal and polyclonal antibody. The antibodies were used to localize the endogenous pORF5 protein and detect the expression pattern in Chlamydia-infected cells using an indirect immunofluorescence assay (IFA). At the same time, ELISA was used to determine whether pORF5 plasmid protein was expressed and immunogenic during Ct infection in humans. Results pORF5 was detected a dominant signal in the cytosol of the Chlamydia-infected cells with a pattern similar to that of anti-CPAF. pORF5 also appeared in the RBs and EBs in small quantity. Athough pattern was similarly, pORF5 did not overlap with CPAF. pORF5 protein was strongly recognized antiserum in an ELISA. Conclusion The pORF5 plasmid protein was identified as a secreted protein with good immunogenicity, pORF5 gene was to express the endogenous target protein during human infection.

Purification and immunological characteristics of monoclonal antibody 2H4 against Chlamydia trachomatis pORF5 plasmid protein / 中华微生物学和免疫学杂志

ObjectiveTo purify and characterize the monoclonal antibody (McAb) against Chlamydia trachomatis pORF5 plasmid protein.Methods The hybridoma cells stably secreting specific McAb against pORF5 were cultured in a large scale,and protein G purification by affinity chromatography was used to purify 2H4 McAb.ELISA was used to determine the antibody titer,and identify McAb isotype.Immunofluorescence assay (IFA) and Western blot were performed to detect McAb specificity.Results The purity of 2H4 antibody was 93％,the titer reached 1:1024,and 2H4 McAb was identified to belong to IgG2a isotype,2H4 McAb reacted strongly with the GST-pORF5 fusion protein and endogenous pORF5 protein expressed by Chlamydia trachomatis serovar A,D,L2,Chlamydia muridarum ( MoPn ),Chlamydia psittaci 6BC,but not other chlamydial plasmid proteins and Chlamydia pneumoniae(Cpn) AR39 strain.Conclusion2H4 McAb against pORF5 protein was successfully purified with a high titer and specificity which lay a foundation for further study on pORF5 protein structure and function.

Induction of IL-8 by Chlamydia trachomatis through MAPK pathway rather than NF-kappaB pathway / 中南大学学报(医学版)

OBJECTIVE@#To determine the signaling pathway required for Chlamydial induction of IL-8 expression in epithelial cells.@*METHODS@#The production and localization of IL-8 in Chlamydia-infected Hela 229 cells were monitored using Western blot, immunoflourescence, and ELISA. Activation of MAPK and NF-kappaB signaling pathways were detected by Western blot and immunoflourescence. The effect of different signaling pathways on Chlamydia-induced Il-8 was measured by experiments of chemical inhibitors.@*RESULTS@#IL-8 was induced by Chlamydia and was time-dependant. Chlamydial infection activated MAPK/ERK and MAPK/p38 pathways but not NF-kappaB pathway. Chlamydial induction of IL-8 was blocked by small molecule inhibitors targeting the ERK and p38 pathways.@*CONCLUSION@#Chlamydia-induced IL-8 in cervical epithelial cells, the natural target cell type of Chlamydia trachomatis infection, is dependent on MAPK pathway but not NF-kappaB pathway, which provides important information for further understanding the molecular mechanism of Chlamydia-induced inflammatory pathologies.

Localization and Characterization of Hypothetical Protein CT358 in The Chlamydia trachomatisInfected Cells / 生物化学与生物物理进展

To localize and characterize the hypothetical protein CT358 in the chlamydial infected cells. CT358 gene from the Chlamydia trachomatis (C. trachomatis) serovar D genome was amplified and cloned into the pGEX and pDSRedCI vectors. The recombinant plasmid pGEX-CT358 was constructed and expressed as GST fusion proteins. The GST-CT358 fusion protein was used to immunize mice to raise the antibodies, which specifically recognized CT358 without eross-reacting with other unrelated proteins. The antibodies were then used to localize the endogenous CT358 protein and determine the expression pattern in Chlamydial infected cells using an indirect immunofluorescence assay (IFA). Meanwhile, pDSRedC 1-CT358 recombinant plasmid was transfected to HeLa cells to evaluate the effect of CT358 expression on the subsequent chlamydial infection. The hypothetical protein CT358 was identified in the inclusion membrane of C. trachomatis-infected cells for the first time,and it was detected as early as 12 h after C. trachomatis infection and remained in the inclusion membrane throughout the rest of the infection cycle. Cytosolic expression of CT358 via a transgene failed to affect the subsequent ehlamydial infection. These observations together have demonstrated that CT358 is a newly identified chlamydial inclusion membrane protein, giving the potentially importance for further understanding the mechanisms of chlamydial intracellular parasitism.

Activation of MAPK/ERK and MAPK/P38 is Essential for Proinflammatory Response by Chlamydia trachomatis / 生物化学与生物物理进展

Chlamydial infection in human urogenital tract induces inflammation and causes tissue damage and scarring. It is thought that cytokine production by the Chlamydia-infected cells plays a key role in chlamydial disease processes. Although many cytokines have been detected during chlamydial infection, little is known about the molecular mechanisms on how Chlamydia triggers and sustains the inflammatory cytokine cascades. In the current study, chlamydial infection of the human cervical epithelial cell line HeLa cells can induce the production of IL-8, IL-1α, IL-1β and IL-6. Using inhibitors for probing intracellular kinase signaling pathways required for the Chlamydia-induced cytokines, it was found that the Chlamydia-activated MAPK / P38 pathway is required for the chlamydial induction of IL-1α and IL-6 while both the Chlamydia-activated MAPK/ERK and MAPK/P38 pathways contribute to the production of IL-8.

Localization and Characterization of Hypothetical Protein CT358 in The Chlamydia trachomatis-Infected Cells / 生物化学与生物物理进展

To localize and characterize the hypothetical protein CT358 in the chlamydial infected cells.CT358 gene from the Chlamydia trachomatis(C.trachomatis) serovar D genome was amplified and cloned into the pGEX and pDSRedC1 vectors.The recombinant plasmid pGEX-CT358 was constructed and expressed as GST fusion proteins.The GST-CT358 fusion protein was used to immunize mice to raise the antibodies,which specifically recognized CT358 without cross-reacting with other unrelated proteins.The antibodies were then used to localize the endogenous CT358 protein and determine the expression pattern in Chlamydial infected cells using an indirect immunofluorescence assay(IFA).Meanwhile,pDSRedC1-CT358 recombinant plasmid was transfected to HeLa cells to evaluate the effect of CT358 expression on the subsequent chlamydial infection.The hypothetical protein CT358 was identified in the inclusion membrane of C.trachomatis-infected cells for the first time,and it was detected as early as 12 h after C.trachomatis infection and remained in the inclusion membrane throughout the rest of the infection cycle.Cytosolic expression of CT358 via a transgene failed to affect the subsequent chlamydial infection.These observations together have demonstrated that CT358 is a newly identified chlamydial inclusion membrane protein,giving the potentially importance for further understanding the mechanisms of chlamydial intracellular parasitism.