Immunoprotective role of dendritic cells in Chlamydia muridarum respiratory infection / 中华微生物学和免疫学杂志

Objective:To investigate the role of dendritic cells (DC) in Chlamydia muridarum ( Cm) respiratory infection and their effect on adaptive immune response. Methods:C57BL/6 mice were exposed to 1×10 3 inclusion-forming units (IFU) of Cm through inhalation to establish the mouse model of Cm respiratory infection. The proportion of CD11c + MHCⅡ + DC and the expression of costimulatory molecules (CD40, CD80 and CD86) in spleen tissues were detected by flow cytometry on 0, 3 and 7 d after infection. The expression of IL-12p40, IL-10 and IL-6 at mRNA level in spleen tissues was detected by qPCR. Mouse splenic DC isolated on 7 d after Cm infection were sorted by magnetic beads and then transferred to recipient mice. Th1 response in the recipient mice was measured using intracellular cytokine staining 14 d after infection. Results:Cm respiratory infection induced massive infiltration of DC and promoted the expression of costimulatory molecules on splenic DC. The expression of IL-12 and IL-10 at mRNA level in splenic DC reached the peak on 3 d after infection. Transferring the splenic DC of Cm-infected mice into the recipient mice could alleviate the disease condition in the recipient mice after Cm infection with reduced Cm inclusion-forming units in lung tissues and significantly increased proportion of Th1 cells in lung and spleen tissues. Conclusions:Cm respiratory infection could induce the maturation and activation of DC, which promoted Th1 immune response. DC played an important role in Cm infection.

Neopterin Levels and Indoleamine 2,3-Dioxygenase Activity as Biomarkers of Immune System Activation and Childhood Allergic Diseases

BACKGROUND: Although Th2 immune activation is predominant in allergic diseases, neopterinlevels and indoleamine 2,3-dioxygenase (IDO)-1 activity (kynurenine:tryptophan ratio), which reflect Th1 immune activity, increase with interferon-gamma (IFN-γ) stimulation. We investigated neopterin, tryptophan, and kynurenine levels as biomarkersof the Th1 immune system activation and changes in IDO-1 activityin children with asthma, allergic rhinitis, and atopic dermatitis, as well as the relationship between these biomarkers and the total IgE level, age, and disease severity. METHODS: We divided 205 children (80 girls and 125 boys, four months to 17 years old) into four groups: controls, patients with asthma, patients with allergic rhinitis, and patients with atopic dermatitis. Peripheral venous blood samples were collected. Neopterin levels were determined by an enzyme immunoassay. Tryptophan and kynurenine levels were analyzed using HPLC. IDO-1 enzyme activity was calculated using tryptophan and kynurenine levels. IgE levels were measured. The Mann-Whitney U test, Kruskal-Wallis test, and Conover post-hoc method were used for statistical analysis. RESULTS: Neopterin, tryptophan, and kynurenine levels were higher and IgE levels and IDO-1 enzyme activity were lower in patients with asthma and allergic rhinitis than in controls (P < 0.05). Patients with atopic dermatitis showed higher neopterin, tryptophan, and kynurenine levels, higher IDO-1 activity, and lower IgE levels thancontrols (P < 0.05). CONCLUSIONS: The Th1/Th2 balance is disrupted in children with allergic diseases, concomitant with increased Th1-mediated immune response activation and reduced IgEproduction, which is promoted by Th2-type cytokines.

TLR4-mediated activation of MyD88 signaling induces protective immune response and IL-10 down-regulation in Leishmania donovani infection.

In visceral leishmaniasis, a fragmentary IL-12 driven type 1 immune response along with the expansion of IL-10 producing T-cells correlates with parasite burden and pathogenesis. Successful immunotherapy involves both suppression of IL-10 production and enhancement of IL-12 and nitric oxide (NO) production. As custodians of the innate immunity, the toll-like receptors (TLRs) constitute the first line of defense against invading pathogens. The TLR-signaling cascade initiated following innate recognition of microbes shapes the adaptive immune response. Whereas numerous studies have correlated parasite control to the adaptive response in Leishmania infection, growing body of evidence suggests that the activation of the innate immune response also plays a pivotal role in disease pathogenicity. In this study, using a TLR4 agonist, a Leishmania donovani (LD) derived 29 kDa β 1,4 galactose terminal glycoprotein (GP29), we demonstrated that the TLR adaptor myeloid differentiation primary response protein-88 (MyD88) was essential for optimal immunity following LD infection. Treatment of LD-infected cells with GP29 stimulated the production of IL-12 and NO while suppressing IL-10 production. Treatment of LD-infected cells with GP29 also induced the degradation of IKB and the nuclear translocation of NF-kB, as well as rapid phosphorylation of p38 MAPK and p54/56 JNK. Knockdown of TLR4 or MYD88 using siRNA showed reduced inflammatory response to GP29 in LD-infected cells. Biochemical inhibition of p38 MAPK, JNK or NF-kB, but not p42/44 ERK, reduced GP29-induced IL-12 and NO production in LD-infected cells. These results suggested a potential role for the TLR4-MyD88–IL-12 pathway to induce adaptive immune responses to LD infection that culminated in an effective control of intracellular parasite replication.

Measurement of peripheral blood mononuclear cells producing IFN-Gamma in patients with tuberculosis

The type of immune response induced by tuberculosis (Th1 or Th2) and its correlation with the clinical outcome is unclear. We studied 13 patients with active tuberculosis (TBC). The peripheral blood mononuclear cells producing IFN-gamma (PBMC-IG) were measured by enzyme-linked immunospot (ELISPOT) technique. The control group had ten healthy individuals vaccinated against tuberculosis. We collected blood samples of each patient in two moments: a) in the hospital admission without treatment (TBC1); b) after seven to 20 days of treatment (TBC2). The comparison of the spots forming units of PBMC-IG between TBC group and controls showed that there was a significant difference between TBC1 and control group (p < 0.001) and between TBC2 and control group (p < 0.005), but there was no difference between TBC1 and TBC2 (p > 0.05). A positive correlation was found between PBMC-IG and hemoglobin value, as well as between PBMC-IG and weight loss. There was no correlation between PBMC-IG and other variables [age, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP)]. We conclude that tuberculosis activates Th1 immune response due to increase of PBMC producing IFN-gamma. There was no difference between the first sample (TBC1) and the second sample (TBC2) of PBMC-IG. This result can have occurred due to treatment influence, or can indicate that the immune response reachs a plateau. The positive correlation among PBMC-IG and both hemoglobin level and weight loss indicates that may exist a link between patient's clinical status and the immune response intensity.

Th1 cellular immune response elicited by recombinant adenovirus transduced dendritic cells for HCV-NS3 in vivo / 中国免疫学杂志

Objective:The aim of this study was to explore the vaccine potential of adenovirus transduced DC encoding for HCV nonstructural protein NS3 in a murine model.Methods:Dendritic cells were isolated from bone marrow of BALB/c mice and cultivated with cytokine cocktail for 7 days. Recombinant adenovirus was added to DC cultures at day 7,at a titration of 2?10~9 pfu/10~6 DC/well. FACS and Western blot techniques were used to identify the DC mature state and the protein expression, respectively. BALB/c mice were primed/boosted immunized with DC based vaccines at 3?10~5 cells for one mouse at a 10 day interval. 10 days after the second immunization, cytokines secretion and IFN-? generating T cells response were evaluated by ELISA and ELLISPOT analysis.Results:Our current data indicate that AdNS3 can stimulate the maturation of DC and efficiently express authentic HCV nonstructural proteins in infected cells. BALB/c mice inoculated with AdNS3 transduced DC twice generated strong IFN-? secreting T cells response(P

The study on polarization of Th1 and Th2 immune responses in BALB/c mice infected with toxoplasma gondii / 中国免疫学杂志

Objective:To explore the polarization of Th1 and Th2 immune response and the changes of transcription factor(T-bet and GATA-3) in BALB/c mice infected with toxoplasma gondii.Methods:Sixty BALB/c mice were infected with toxoplasma tachyzoite(1?104/m,0.5 ml) by intraperitoneal injection and thirty BALB/c mice only received an injection of same amount of normal saline as control.After injection,two mice of infection group and one mouse of control group were killed in odd number days.Then,the serum IFN-? and IL-4 were measured by ELISA,and the mRNA expression of T-bet and GATA-3 in mice spleens were detected by Real-Time RT-PCR.Results:In the infection group of mice,the IFN-? was remarkable increased at the fourth day and kept the peak from the 5th day to 7th day.Then,it decreased to normal level at 9th day postinjection;but IL-4 was remarkable increased at the 8th day and reached to the peak at 9th day.Then it decreased to normal level at 15th day postinjection.The mRNA of T-bet expression was increased at the third day and kept the peak from the 5th day to 7th day.Then,it decreased to normal level at 9th day postinjection.The mRNA of GATA-3 expression was increased at the 7th day and rised to the peak at 11th day.Then,it decreased to normal level at 13th day postinjection.There were not obvious changes of IFN-? and IL-4 or T-bet and GATA-3 in normal mice.Conclusion:The Th1 immune response is dominant in acute infection when mice are infected by toxoplasma.Then it biases toward Th2 response at 9th day to 13th day postinfection.The shift of Th1/Th2 polarization influences the finale of toxoplasma infection.