Overcoming resistance to STING agonist therapy to incite durable protective antitumor immunity.

BACKGROUND: Activating the Stimulator of Interferon Genes (STING) adaptor incites antitumor immunity against immunogenic tumors in mice, prompting clinical trials to test STING activators. However, STING signaling in the tumor microenvironment (TME) during development of Lewis lung carcinoma (LLC) suppresses antitumor immunity to promote tumor growth. We hypothesized that local immune balance favoring suppression of antitumor immunity also attenuates antitumor responses following STING activation. The purpose of this study was to evaluate how STING activation impacts antitumor responses in mice bearing LLC tumors. METHODS: Mice bearing established LLC tumors were treated with synthetic cyclic diadenyl monophosphate (CDA) to activate STING. Mice were monitored to assess LLC tumor growth, survival and protective antitumor immunity. Transcriptional and metabolic analyses were used to identify pathways responsive to CDA, and mice were co-treated with CDA and drugs that disrupt these pathways. RESULTS: CDA slowed LLC tumor growth but most CDA-treated mice (77%) succumbed to tumor growth. No evidence of tumor relapse was found in surviving CDA-treated mice at experimental end points but mice were not immune to LLC challenge. CDA induced rapid increase in immune regulatory pathways involving programmed death-1 (PD-1), indoleamine 2,3 dioxygenase (IDO) and cyclooxygenase-2 (COX2) in the TME. PD-1 blockade enhanced antitumor responses to CDA and increased mouse survival but mice did not eliminate primary tumor burdens. Two IDO inhibitor drugs had little or no beneficial effects on antitumor responses to CDA. A third IDO inhibitor drug synergized with CDA to enhance tumor control and survival but mice did not eliminate primary tumor burdens. In contrast, co-treatments with CDA and the COX2-selective inhibitor celecoxib controlled tumor growth, leading to uniform survival without relapse, and mice acquired resistance to LLC re-challenge and growth of distal tumors not exposed directly to CDA. Thus, mice co-treated with CDA and celecoxib acquired stable and systemic antitumor immunity. CONCLUSIONS: STING activation incites potent antitumor responses and boosts local immune regulation to attenuate antitumor responses. Blocking STING-responsive regulatory pathways synergizes with CDA to enhance antitumor responses, particularly COX2 inhibition. Thus, therapy-induced resistance to STING may necessitate co-treatments to disrupt regulatory pathways responsive to STING in patients with cancer.

Facilitators and Barriers Associated with Uptake of HIV Self-Testing among Men Who Have Sex with Men in Chongqing, China: A Cross-Sectional Survey.

While studies on human immunodeficiency virus self-testing (HIVST) continue to accumulate after the World Health Organization's recommendation of HIVST as an additional approach to HIV testing services in 2016, few studies have focused on men who have sex with men (MSM) in Chinese cities. A cross-sectional study was conducted to describe the HIVST status of MSM in Chongqing, China. MSM participants were recruited by random sampling, and qualified interviewers collected data, using confidential self-administered questionnaires. Blood specimens were collected for HIV antibody detection. The survey evaluated the uptake and accuracy of HIVST kits and identified factors that may be associated with HIVST. The proportion of HIVST uptake was 15.6%. The sensitivity and specificity of HIVST were 74.2% (95% confidence interval [CI] 66.6%-80.7%) and 99.0% (95% CI 96.9%-99.7%), respectively. The consistency between the HIVST kit and antibody detection results was 90.5% (95% CI 87.5%-93.0%), and the Kappa value was 0.777 (p < 0.001). The positive predictive value of self-testing kits is 80.9% and the negative predictive value is 17.7%. Having been tested ≥2 times in the last year, higher educational levels, and higher scores of basic HIV/AIDS knowledge facilitated higher uptake of HIVST. Self-reported existing barriers for HIVST uptake included older age, marital status, and having resided in Chongqing for more than two years.

Stimulator of interferon genes agonists attenuate type I diabetes progression in NOD mice.

Reagents that activate the signaling adaptor stimulator of interferon genes (STING) suppress experimentally induced autoimmunity in murine models of multiple sclerosis and arthritis. In this study, we evaluated STING agonists as potential reagents to inhibit spontaneous autoimmune type I diabetes (T1D) onset in non-obese diabetic (NOD) female mice. Treatments with DNA nanoparticles (DNPs), which activate STING when cargo DNA is sensed, delayed T1D onset and reduced T1D incidence when administered before T1D onset. DNP treatment elevated indoleamine 2,3 dioxygenase (IDO) activity, which regulates T-cell immunity, in spleen, pancreatic lymph nodes and pancreas of NOD mice. Therapeutic responses to DNPs were partially reversed by inhibiting IDO and DNP treatment synergized with insulin therapy to further delay T1D onset and reduce T1D incidence. Treating pre-diabetic NOD mice with cyclic guanyl-adenyl dinucleotide (cGAMP) to activate STING directly delayed T1D onset and stimulated interferon-αß (IFN-αß), while treatment with cyclic diguanyl nucleotide (cdiGMP) did not delay T1D onset or induce IFN-αß in NOD mice. DNA sequence analyses revealed that NOD mice possess a STING polymorphism that may explain differential responses to cGAMP and cdiGMP. In summary, STING agonists attenuate T1D progression and DNPs enhance therapeutic responses to insulin therapy.

Long noncoding RNA SNHG12 promotes the progression of cervical cancer via modulating miR-125b/STAT3 axis.

Increasing evidence showed that long noncoding RNAs (lncRNAs) played an important role in the occurrence and development of tumors. To date, lncRNA small nucleolar RNA host gene 12 (SNHG12) has revealed an oncogenic role in various tumors. However, the role of SNHG12 in cervical cancer is still unclear. Therefore, we focused on the biological function and molecular mechanism of SNHG12 in the tumorigenesis of cervical cancer. In this study, the expression of miR-125b was observably downregulated in cervical cancer cells. Meanwhile, the expression of SNHG12 was obviously upregulated in cervical cancer cell lines (HeLa, SiHa, Caski, C4-1, and C33A) compared with the immortalized cervical epithelial cells. The further assay showed that miR-125b was a target of SNHG12 in cervical cancer. Moreover, a negative relationship between miR-125b and SNHG12 was found in cervical cancer. In addition, SNHG12 inhibition restrained the proliferation, migration, and invasion of cervical cancer cells. Meanwhile, miR-125b mimics repressed the expression of signal transducer and activator of transcription 3 (STAT3). The further assay showed that STAT3 was a target of miR-125b in cervical cancer. In addition, sh-STAT3 repressed the migration and invasion of cervical cancer cells. Furthermore, it showed that miR-125b inhibitors reversed STAT3 expression restrained by the reduction of SNHG12 expression. In general, SNHG12 modulated STAT3 by sponging miR-125b in cervical cancer and played an important role in the development of cervical cancer.

Lentiviral-mediated microRNA-26b up-regulation inhibits proliferation and migration of hepatocellular carcinoma cells.

Hepatocellular carcinoma (HCC) is a frequently occurred malignancy worldwide with a high mortality. The treatment for HCC is still controversial. Emerging evidences have demonstrated that microRNAs (miRs) play a role in HCC. This study aims to investigate the effects of lentiviral-mediated miRNA-26b (miR-26b) on the proliferation and metastasis of HCC cells. The normal hepatic cell line HL-7702 and HCC cell lines HepG2 (without metastatic potential), SMMC-7721 (with low metastatic potential) and MHCC97H (with high metastatic potential) were purchased for our experiment. The lentiviral-mediated miR-26b overexpression (miR-26b-LV) and low expression (sh-miR-26b) were constructed to transfect the cells. The miR-26b expression and expressions of Karyopherin α-2 (KPNA2), matrix metalloproteinase 1 (MMP-1), MMP-7 and MMP-14 were determined by RT-qPCR and western blot analysis. The proliferation and metastasis of transfected HCC cells were detected by MTT and Transwell assay respectively. The miR-26b expressions were decreased significantly in MHCC97H cells. With lentiviral-mediated miR-26b overexpression, the proliferation and migration of HepG2, MHCC97H and SMMC-7721 cells were decreased significantly. The RT-qPCR and western blot analysis results revealed that the mRNA and protein expressions of KPNA2, MMP-1, MMP-7 and MMP-14 were decreased by lentiviral-mediated miR-26b overexpression. All the above indexes in the HepG2, MHCC97H and SMMC-7721 cells treated by sh-miR-26b exhibited opposite trends. These results show that overexpressed miR-26b could inhibit the proliferation and metastasis of HCC cells significantly, which provides a novel target and theoretical foundation for the treatment of HCC.

[Effects of Pim-1 inhibitor on mouse model of inflammatory bowel disease induced by TNBS].

OBJECTIVE: To explore the role of Pim-1 in the pathology of inflammatory bowel disease and the potential effect of Pim-1 inhibitor on treating such disease.
 Methods: Forty-five BALB/c mice were randomly divided into 5 groups (n=9): A normal control group, a inflammatory bowel disease group, two different dose of Pim-1 inhibitor treatment groups, and steroidhormone treatment group. The model of inflammatory bowel disease was induced by intracolonic administration of 2, 4, 6-trinitrobenzenestdfonic acid (TNBS) and ethanol mixture. Mice were treated with Pim-1 inhibitor [intraperitoneal inject, 5 or 10 mg/(kg.d)] for 5 days and prednisone (intragastric administration, 0.1 mg/d) for 5 days. The DAI, colon length, gross score and pathological grade were evaluated. The expressions of T cell master transcription factors T-box expressed in T cells (T-bet), GATA binding protein 3 (GATA-3), RA orphan receptorγ (RORγt) and forkhead box P3 (Foxp3) were measured by Real-time PCR and Western blot, respectively.
 Results: Pim-1 inhibitor and prednisone showed therapeutic effect on acute TNBS colitis in vivo. GATA3 and RORγt were significantly up-regulated in acute TNBS colitis (P<0.05). In contrast, the expression of Foxp3 was suppressed in the inflammatory bowel disease group, whereas it did not cause any significant change in T-bet expression (P>0.05). Administration of Pim-1 inhibitor and prednisone resulted in suppression of GATA3, RORγt expression, and the increase of Foxp3 expression (P<0.05). Administration of Pim-1 inhibitor and prednisone resulted in inhibition of T-bet mRNA expression (P<0.05), but only prednisone could inhibit T-bet protein expression (P>0.05).
 Conclusion: Pim-1 inhibitor significantly suppresses Th2- and Th17-type immune responses. Furthermore, Pim-1 inhibitor could induce T-cell differentiation towards a Treg phenotype. Pim-1 inhibitor has therapeutic effect on acute TNBS colitis.

YM155 enhances docetaxel efficacy in ovarian cancer.

YM155 (Sepantronium bromide) is a potent small molecule inhibitor of survivin by suppression of survivin expression and shows the promising anticancer activity in many types of cancers. Docetaxel (Taxotere®) is a member of the taxane drugs used in the treatment of a number of cancers in clinic. Despite the therapeutic efficacy of docetaxel is encouraging, the emergent resistance is an urgent issue. In this study, we investigate the effect of YM155 on docetaxel efficacy in ovarian cancer cells. Our data showed that YM155 actively induced cell growth inhibition, cell cycle arrest and apoptosis with downregualtion of survivin in ovarian cancer cells. Moreover, YM155 increased the intracellular ROS levels, and pretreatment with either NAC or GSH partially reversed the YM155-induced ROS accumulation and apoptosis only in the parental A2780 cells, but not in the resistant A2780/Taxol cells. Furthermore, YM155 enhanced docetaxel efficacy to inhibit the growth and induce apoptosis in ovarian cancer cells. Take together, our results suggested that combination of YM155 and docetaxel may be a feasible strategy for the treatment of ovarian cancer.

Crizotinib synergizes with cisplatin in preclinical models of ovarian cancer.

Crizotinib, a small molecule inhibitor of anaplastic lymphoma kinase (ALK), c-ros oncogene 1 (ROS1) and c-MET (also called MET or hepatocyte growth factor receptor), has been approved by the Food and Drug Administration for the treatment of patients with advanced non-small cell lung cancer whose tumors have rearrangements in the ALK or ROS1 gene. However, the anticancer effect of crizotinib on ovarian cancer is still unclear. In this study, our data show that crizotinib can actively induce cell growth inhibition, cell cycle arrest at G2/M phase and apoptosis with the decreasing phosphorylation of the downstream signaling effectors AKT and ERK in human ovarian cancer cells. Crizotinib also increases the intracellular reactive oxidative species (ROS) levels, and pretreating with ROS scavenger N-acety-L-cysteine partially reverses crizotinib-induced apoptosis. Moreover, crizotinib can synergistically inhibit ovarian cancer cells growth in vitro and in vivo when combines with cisplatin. Altogether, crizotinib potently potentiates the activity of cisplatin in ovarian cancer, suggesting the synergistic effect of crizotinib and cisplatin may be valuable for ovarian cancer patients' treatment.

Corticosteroid in Combination with Leflunomide and Mesenchymal Stem Cells for Treatment of Pediatric Idiopathic Pulmonary Hemosiderosis.

Background: This study evaluated the efficiency of corticosteroid, leflunomide and mesenchymal stem cells (MSCs) in the treatment of pediatric idiopathic pulmonary hemosiderosis (IPH). Methods: Ten patients were included in the study. The diagnosis of IPH was based on clinical symptoms, laboratory examinations and pulmonary hemosiderosis. Induction therapy consisted of methylprednisolone pulse therapy, followed by prednisone plus leflunomide. Maintenance therapy consisted of low-dose prednisone, leflunomide and administration of MSCs. Results: All the patients achieved complete response after treatment with corticosteroid, leflunomide and MSCs. The median follow-up was 23 months (range: 4-34 months). Moreover, administration of MSCs induced an increase in the percentage of CD4+ CD25+ regulatory T cells but a decrease in the percentage of Th17 cells. Conclusion: Treatment with corticosteroid, leflunomide and MSCs for pediatric IPH was safe and effective.

Virus Infections Incite Pain Hypersensitivity by Inducing Indoleamine 2,3 Dioxygenase.

Increased pain sensitivity is a comorbidity associated with many clinical diseases, though the underlying causes are poorly understood. Recently, chronic pain hypersensitivity in rodents treated to induce chronic inflammation in peripheral tissues was linked to enhanced tryptophan catabolism in brain mediated by indoleamine 2,3 dioxygenase (IDO). Here we show that acute influenza A virus (IAV) and chronic murine leukemia retrovirus (MuLV) infections, which stimulate robust IDO expression in lungs and lymphoid tissues, induced acute or chronic pain hypersensitivity, respectively. In contrast, virus-induced pain hypersensitivity did not manifest in mice lacking intact IDO1 genes. Spleen IDO activity increased markedly as MuLV infections progressed, while IDO1 expression was not elevated significantly in brain or spinal cord (CNS) tissues. Moreover, kynurenine (Kyn), a tryptophan catabolite made by cells expressing IDO, incited pain hypersensitivity in uninfected IDO1-deficient mice and Kyn potentiated pain hypersensitivity due to MuLV infection. MuLV infection stimulated selective IDO expression by a discreet population of spleen cells expressing both B cell (CD19) and dendritic cell (CD11c) markers (CD19+ DCs). CD19+ DCs were more susceptible to MuLV infection than B cells or conventional (CD19neg) DCs, proliferated faster than B cells from early stages of MuLV infection and exhibited mature antigen presenting cell (APC) phenotypes, unlike conventional (CD19neg) DCs. Moreover, interactions with CD4 T cells were necessary to sustain functional IDO expression by CD19+ DCs in vitro and in vivo. Splenocytes from MuLV-infected IDO1-sufficient mice induced pain hypersensitivity in uninfected IDO1-deficient recipient mice, while selective in vivo depletion of DCs alleviated pain hypersensitivity in MuLV-infected IDO1-sufficient mice and led to rapid reduction in splenomegaly, a hallmark of MuLV immune pathogenesis. These findings reveal critical roles for CD19+ DCs expressing IDO in host responses to MuLV infection that enhance pain hypersensitivity and cause immune pathology. Collectively, our findings support the hypothesis elevated IDO activity in non-CNS due to virus infections causes pain hypersensitivity mediated by Kyn. Previously unappreciated links between host immune responses to virus infections and pain sensitivity suggest that IDO inhibitors may alleviate heightened pain sensitivity during infections.

STING Promotes the Growth of Tumors Characterized by Low Antigenicity via IDO Activation.

Cytosolic DNA sensing is an important process during the innate immune response that activates the stimulator of interferon genes (STING) adaptor and induces IFN-I. STING incites spontaneous immunity during immunogenic tumor growth and accordingly, STING agonists induce regression of therapy-resistant tumors. However DNA, STING agonists, and apoptotic cells can also promote tolerogenic responses via STING by activating immunoregulatory mechanisms such as indoleamine 2,3 dioxygenase (IDO). Here, we show that IDO activity induced by STING activity in the tumor microenvironment (TME) promoted the growth of Lewis lung carcinoma (LLC). Although STING also induced IDO in tumor-draining lymph nodes (TDLN) during EL4 thymoma growth, this event was insufficient to promote tumorigenesis. In the LLC model, STING ablation enhanced CD8(+) T-cell infiltration and tumor cell killing while decreasing myeloid-derived suppressor cell infiltration and IL10 production in the TME. Depletion of CD8(+) T cells also eliminated the growth disadvantage of LLC tumors in STING-deficient mice, indicating that STING signaling attenuated CD8(+) T-cell effector functions during tumorigenesis. In contrast with native LLC tumors, STING signaling neither promoted growth of neoantigen-expressing LLC, nor did it induce IDO in TDLN. Similarly, STING failed to promote growth of B16 melanoma or to induce IDO activity in TDLN in this setting. Thus, our results show how STING-dependent DNA sensing can enhance tolerogenic states in tumors characterized by low antigenicity and how IDO inhibition can overcome this state by attenuating tumor tolerance. Furthermore, our results reveal a greater complexity in the role of STING signaling in cancer, underscoring how innate immune pathways in the TME modify tumorigenesis in distinct tumor settings, with implications for designing effective immunotherapy trials. Cancer Res; 76(8); 2076-81. ©2016 AACR.

Evaluation of Time-Phase Effect on 18F-FDG PET/CT Delineation Methods for Treatment Planning of Nasopharyngeal Carcinoma.

PURPOSE: Tumor boundary delineation using F-FDG PET/CT is a promising tool for radiotherapy applications, but no consensus has been established regarding the optimal delineation method. Time-phase variability of F-FDG PET/CT imaging frequently affects metabolically active volumes and treatment planning for nasopharyngeal carcinoma (NPC). This study aimed to evaluate the time-phase robustness of 8 methods commonly used for tumor volume delineation in NPC. PATIENTS AND METHODS: Twenty patients with biopsy-proven NPC were included and underwent multiple time-phase F-FDG PET/CT imaging. Gross tumor volumes (GTVs), absolute SUV, gradient-based watershed segmentation (GTV-GWT), and anatomic biologic contouring (GTV-ABC) values were determined. The volume of overlap between GTV-CT and the 8 PET-based GTVs was enclosed and the overlap fraction (OF-CT) calculated. Color matrix was used to semiquantify the time-phase differences. Gross tumor volume values obtained with different methods were recorded and compared using paired t test. Time-phase differences of GTVs and SUVmax were compared among groups by analysis of variance with Tukey honest significance tests. The coefficients of variation were computed to assess intrapatient time-phase variability. Similarity coefficient was calculated to evaluate similarity. RESULTS: Differences were observed between GTVs obtained at different time points using various delineation procedures. Nonsignificantly higher percentages were obtained for GTV-GWT (88.17%) and GTV-ABC (86.98%) compared with other methods, showing their robustness. GTV-40% (0.81-0.88) and GTV-ABC (0.82-0.88) indicated higher similarity with GTV-MRI than the other methods. CONCLUSIONS: PET/CT-based GTV-ABC between 35 and 55 minutes should be the first choice for NPC treatment planning.

Volasertib suppresses tumor growth and potentiates the activity of cisplatin in cervical cancer.

Volasertib (BI 6727), a highly selective and potent inhibitor of PLK1, has shown broad antitumor activities in the preclinical and clinical studies for the treatment of several types of cancers. However, the anticancer effect of volasertib on cervical cancer cells is still unknown. In the present study, we show that volasertib can markedly induce cell growth inhibition, cell cycle arrest at G2/M phase and apoptosis with the decreased protein expressions of PLK1 substrates survivin and wee1 in human cervical cancer cells. Furthermore, volasertib also enhances the intracellular reactive oxidative species (ROS) levels, and pretreated with ROS scavenger N-acety-L-cysteine totally blocks ROS generation but partly reverses volasertib-induced apoptosis. In addition, volasertib significantly potentiates the activity of cisplatin to inhibit the growth of cervical cancer in vitro and in vivo. In brief, volasertib suppresses tumor growth and potentiates the activity of cisplatin in cervical cancer, suggesting the combination of volasertib and cisplatin may be a promising strategy for the treatment of patients with cervical cancer.

Ovarian cancer initially presenting with isolated ipsilateral superficial inguinal lymph node metastasis: a case study and review of the literature.

Isolated superficial inguinal metastases without any extended intra-abdominal spread is a rare event in patients with ovarian carcinoma. Here we report an isolated superficial inguinal metastasis in a patient with primary ovarian cancer. A 54-year-old Chinese patient with primary ovarian cancer, had an isolated painless enlarged right groin swelling (3×2cm) as the only manifestation, preoperative pathology confirmed metastatic adenocarcinoma. Gynecologic examination, transvaginal ultrasonography of the abdominopelvic cavity revealed a 5-cm mixed, right adnexal mass. At exploratory laparotomy, there was little intra-abdominal tumor dissemination but 100 ml of faint yellow peritoneal fluid and a 5-cm right ovarian tumor with intact capsule. Staging operation was performed and postoperative pathology confirmed adenocarcinoma located within right ovarian, with no evidence of involvement of other sites. Then the patient received adjuvant chemotherapy for Stage IVB. Five years later, the patient is currently still alive without evidence of recurrent disease. This case indicate that ovarian carcinoma isn't a disease localized only within the intra-peritoneal cavity, isolated superficial inguinal lymph node metastasis might occur in rare cases via potential lymphatic and (or) hematogenous route under special conditions. We propose the need to investigate the possible mechanisms, risk factors, metastatic patterns, the biology and natural history of such patients in a large-scale and multicenter analysis. Furthermore, efforts should be made for earlier and differential diagnosis and finally prolong survival time for such patients.

Addition of hepatectomy decreases liver recurrence and leads to long survival in hilar cholangiocarcinoma.

AIM: To evaluate hepatic recurrence and prognostic factors for survival in patients with surgically resected hilar cholangiocarcinoma in a single institution over the last 13 years. METHODS: From 1994 to 2007, all patients with hilar cholangiocarcinoma referred to a surgical clinic were evaluated. Demographic data, tumor characteristics, and outcome were analyzed retrospectively. Outcome was compared in patients who underwent additional liver resection with resection of the tumor. RESULTS: Of the 69 patients submitted to laparotomy for tumor resection, curative resection (R(0) resection) was performed in 40 patients, and palliative resection in 29. Thirty-one patients had only duct resection, and 38 patients had combined duct resection with liver resection including 34 total or part caudate lobes. Curative rates with the combined hepatectomy were significantly improved compared with those without additional hepatectomy (27/38 vs 13/31; chi2 = 5.94, P < 0.05). Concomitant liver resection was associated with a decreased incidence of initial recurrence in liver one year after surgery (11/38 vs 23/31; chi2 = 13.98, P < 0.01). The 3-year survival rate after R(0) resection was 30.7% and was 10.5% for palliative resection. R(0) resection improved the 3-year survival rate (30.7% vs 10.5%; chi2 = 12.47, P < 0.01). CONCLUSION: Hepatectomy, especially including the caudate lobe combined with bile duct resection should be considered standard treatment to cure hilar cholangiocarcinoma.

[Association of gene polymorphisms of CYP1B1 with intrahepatic cholestasis of pregnancy].

OBJECTIVE: To study the role of gene polymorphisms of cytochrome P4501B1 (CYP1B1) in exon 2 codon 119(G-T) and exon 3 codon 432(C-G) in intrahepatic cholestasis of pregnancy (ICP). METHODS: Gene polymorphisms of CYP1B1 in exon 2 codon 119 and exon 3 codon 432 were detected with Allele-specific polymerase chain reaction (ASA-PCR) and di-allele-specific-amplification with artificially modified primer (diASA-AMP) techniques in a case-control study, which included 100 ICP patients and 100 healthy pregnant women as controls. RESULTS: (1) The ICP patients had higher frequency of allele T on codon 119 of CYP1B1 gene than the controls (P < 0.05). Significant differences of frequencies were found in genotype GG, GT and TT between the ICP patients and the controls (P > 0.05). Compared to the wide-type GG, the ICP risks of the women with genotype TT homozygous and GT heterozygous increased by 3.6 and 2.435 times, respectively. (2) No genotype GG was found in this study. There were no significant differences between the ICP patients and the controls in the genotype distributions (CC and CG) and allele frequencies (C and G) of CYP1B1 polymorphism in exon 3 codon 432 (P > 0.05). CONCLUSION: Gene polymorphism of CYP1B1 in exon 2 codon 119 may be associated with the risk of ICP. The mutation of CYP1B1 gene increases the risk of ICP. The gene polymorphism of CYP1B1 in exon 3 codon 432 is not associated with the risk of ICP.

Control of virus-specific CD8+ T-cell exhaustion and immune-mediated pathology by E3 ubiquitin ligase Cbl-b during chronic viral infection.

A characteristic feature in the immune response to many persistent viral infections is the dysfunction or deletion of antigen-specific T cells (exhaustion). This down-regulation of virus-specific T-cell response represents a critical control mechanism that exists within T-cell activation pathways to prevent lethal disease by inappropriate responses against disseminating virus infections. However, the molecular mechanisms by which the immune system determines whether to mount a full response to such infections remain largely unexplored. Here, we have established that in the murine lymphocytic choriomeningitis virus (LCMV) model, induction of the T-cell receptor signaling inhibitor molecule E3 ligase Cbl-b is critically involved in this decision. In particular, our data revealed that Cbl-b controls the program responsible for T-cell tolerance (exhaustion) induction during a chronic viral infection. Thus, Cbl-b(-/-) mice infected with a low dose of LCMV Docile mount a strong CD8(+) T-cell response that rapidly clears the infection, and the animals remain healthy; in contrast, down-regulation of the epitope-specific CD8(+) T-cell population in persistently infected Cbl-b(-/-) mice, compared to that in chronically infected B6 mice, was significantly delayed, and this was associated with increased morbidity and eventual death in nearly 20% of the animals. Interestingly, infection of Cbl-b(-/-) mice with a moderate virus dose resulted in rapid death with 100% mortality by 7 to 8 days after infection, caused by a dysregulated antiviral T-cell response, whereas the infected B6 mice survived and remained healthy. In conclusion, our results suggest that Cbl-b is critically involved in T-cell exhaustion and prevention of lethal disease.

Regulation of immune response and inflammatory reactions against viral infection by VCAM-1.

The migration of activated antigen-specific immune cells to the target tissues of virus replication is controlled by the expression of adhesion molecules on the vascular endothelium that bind to ligands on circulating lymphocytes. Here, we demonstrate that the adhesion pathway mediated by vascular cell adhesion molecule 1 (VCAM-1) plays a role in regulating T-cell-mediated inflammation and pathology in nonlymphoid tissues, including the central nervous system (CNS) during viral infection. The ablation of VCAM-1 expression from endothelial and hematopoietic cells using a loxP-Cre recombination strategy had no major effect on the induction or overall tissue distribution of antigen-specific T cells during a systemic infection with lymphocytic choriomeningitis virus (LCMV), except in the case of lung tissue. However, enhanced resistance to lethal LCM and the significantly reduced magnitude and duration of footpad swelling observed in VCAM-1 mutant mice compared to B6 controls suggest a significant role for VCAM-1 in promoting successful local inflammatory reactions associated with efficient viral clearance and even life-threatening immunopathology under particular infection conditions. Interestingly, analysis of the infiltrating populations in the brains of intracerebrally infected mice revealed that VCAM-1 deletion significantly delayed migration into the CNS of antigen-presenting cells (macrophages and dendritic cells), which are critical for optimal stimulation of migrating virus-specific CD8(+) T cells initiating a pathological cascade. We propose that the impaired migration of these accessory cells in the brain may explain the improved clinical outcome of infection in VCAM-1 mutant mice. Thus, these results underscore the potential role of VCAM-1 in regulating the immune response and inflammatory reactions against viral infections.

Perforin and Fas cytolytic pathways coordinately shape the selection and diversity of CD8+-T-cell escape variants of influenza virus.

Antigenic variation is a viral strategy exploited to promote survival in the face of the host immune response and represents a major challenge for efficient vaccine development. Influenza viruses are pathogens with high transmissibility and mutation rates, enabling viral escape from immunity induced by prior infection or vaccination. Intense selection from neutralizing antibody drives antigenic changes in the surface glycoproteins, resulting in emergence of new strains able to reinfect hosts immune to previously circulating viruses. CD8+ cytotoxic T cells (CTLs) also provide protective immunity from influenza virus infection and may contribute to the antigenic evolution of influenza viruses. Utilizing mice transgenic for an influenza virus NP366-374 peptide-specific T-cell receptor, we demonstrated that the respiratory tract is a suitable site for generation of escape variants of influenza virus selected by CTL in vivo. In this report the contributions of the perforin and Fas pathways utilized by influenza virus-specific CTLs in viral clearance and selection of CTL escape variants have been evaluated. While transgenic CTLs deficient in either perforin- or Fas-mediated pathways are efficient in initial pulmonary viral control, variant virus emergence was observed in all the mice studied, although the spectrum of viral CTL escape variants selected varied profoundly. Thus, a less-restricted repertoire of escape variants was observed in mice with an intact perforin cytotoxic pathway compared with a limited variant diversity in perforin pathway-deficient mice, although maximal variant diversity was observed in mice having both Fas and perforin pathways intact. We conclude that selection of viral CTL escape variants reflects coordinate action between the tightly controlled perforin/granzyme pathway and the more promiscuous Fas/FasL pathway.

Differential tissue-specific regulation of antiviral CD8+ T-cell immune responses during chronic viral infection.

The hallmarks of the immune response to viral infections are the expansion of antigen-specific CD8(+) cytotoxic T lymphocytes (CTLs) after they encounter antigen-presenting cells in the lymphoid tissues and their subsequent redistribution to nonlymphoid tissues to deal with the pathogen. Control mechanisms exist within CTL activation pathways to prevent inappropriate CTL responses against disseminating infections with a broad distribution of pathogen in host tissues. This is demonstrated during overwhelming infection with the noncytolytic murine lymphocytic choriomeningitis virus, in which clonal exhaustion (anergy and/or deletion) of CTLs prevents immune-mediated pathology but allows persistence of the virus. The mechanism by which the immune system determines whether or not to mount a full response to such infections is unknown. Here we present data showing that the initial encounter of specific CTLs with infected cells in lymphoid tissues is critical for this decision. Whether the course of the viral infection is acute or persistent for life primarily depends on the degree and kinetics of CTL exhaustion in infected lymphoid tissues. Virus-driven CTL expansion in lymphoid tissues resulted in the migration of large quantities of CTLs to nonlymphoid tissues, where they persisted at stable levels. Surprisingly, although virus-specific CTLs were rapidly clonally exhausted in lymphoid tissues under conditions of chronic infection, a substantial number of them migrated to nonlymphoid tissues, where they retained an effector phenotype for a long time. However, these cells were unable to control the infection and progressively lost their antiviral capacities (cytotoxicity and cytokine secretion) in a hierarchical manner before their eventual physical elimination. These results illustrate the differential tissue-specific regulation of antiviral T-cell responses during chronic infections and may help us to understand the dynamic relationship between antigen and T-cell populations in many persistent infections in humans.