Insight into the Mechanisms of Adenovirus Capsid Disassembly from Studies of Defensin Neutralization

Defensins are effectors of the innate immune response with potent antibacterial activity. Their role in antiviral immunity, particularly for non-enveloped viruses, is poorly understood. We recently found that human alpha-defensins inhibit human adenovirus (HAdV) by preventing virus uncoating and release of the endosomalytic protein VI during cell entry. Consequently, AdV remains trapped in the endosomal/lysosomal pathway rather than trafficking to the nucleus. To gain insight into the mechanism of defensin-mediated neutralization, we analyzed the specificity of the AdV-defensin interaction. Sensitivity to alpha-defensin neutralization is a common feature of HAdV species A, B1, B2, C, and E, whereas species D and F are resistant. Thousands of defensin molecules bind with low micromolar affinity to a sensitive serotype, but only a low level of binding is observed to resistant serotypes. Neutralization is dependent upon a correctly folded defensin molecule, suggesting that specific molecular interactions occur with the virion. CryoEM structural studies and protein sequence analysis led to a hypothesis that neutralization determinants are located in a region spanning the fiber and penton base proteins. This model was supported by infectivity studies using virus chimeras comprised of capsid proteins from sensitive and resistant serotypes. These findings suggest a mechanism in which defensin binding to critical sites on the AdV capsid prevents vertex removal and thereby blocks subsequent steps in uncoating that are required for release of protein VI and endosomalysis during infection. In addition to informing the mechanism of defensin-mediated neutralization of a non-enveloped virus, these studies provide insight into the mechanism of AdV uncoating and suggest new strategies to disrupt this process and inhibit infection

Ustekinumab as Induction and Maintenance Therapy for Crohn’s Disease

BACKGROUND Ustekinumab, a monoclonal antibody to the p40 subunit of interleukin-12 and inter-leukin-23, was evaluated as an intravenous induction therapy in two populations with moderately to severely active Crohn’s disease. Ustekinumab was also evaluated as subcutaneous maintenance therapy. METHODS We randomly assigned patients to receive a single intravenous dose of ustekinumab (either 130 mg or approximately 6 mg per kilogram of body weight) or placebo in two induction trials. The UNITI-1 trial included 741 patients who met the criteria for primary or secondary nonresponse to tumor necrosis factor (TNF) antagonists or had unacceptable side effects. The UNITI-2 trial included 628 patients in whom conventional therapy failed or unacceptable side effects occurred. Patients who completed these induction trials then participated in IM-UNITI, in which the 397 patients who had a response to ustekinumab were randomly assigned to receive subcutaneous maintenance injections of 90 mg of ustekinumab (either every 8 weeks or every 12 weeks) or placebo. The primary end point for the induction trials was a clinical response at week 6 (defined as a decrease from baseline in the Crohn’s Disease Activity Index [CDAI] score of ≥100 points or a CDAI score <150). The primary end point for the maintenance trial was remission at week 44 (CDAI score <150). RESULTS The rates of response at week 6 among patients receiving intravenous ustekinumab at a dose of either 130 mg or approximately 6 mg per kilogram were significantly higher than the rates among patients receiving placebo (in UNITI-1, 34.3%, 33.7%, and 21.5%, respectively, with P≤0.003 for both comparisons with placebo; in UNITI-2, 51.7%, 55.5%, and 28.7%, respectively, with P<0.001 for both doses). In the groups receiving maintenance doses of ustekinumab every 8 weeks or every 12 weeks, 53.1% and 48.8%, respectively, were in remission at week 44, as compared with 35.9% of those receiving placebo (P = 0.005 and P = 0.04, respectively). Within each trial, adverse-event rates were similar among treatment groups. CONCLUSIONS Among patients with moderately to severely active Crohn’s disease, those receiving intravenous ustekinumab had a significantly higher rate of response than did those receiving placebo. Subcutaneous ustekinumab maintained remission in patients who had a clinical response to induction therapy. (Funded by Janssen Research and Development; ClinicalTrials.gov numbers, NCT01369329, NCT01369342, and NCT01369355.

Minute findings by magnifying colonoscopy are useful for the evaluation of ulcerative colitis

authorMethods:Liver injury was induced by intravenous injection of Con A. Anti-mouse MIP-1α antibody, recombinant murine-MIP-1α and gadolinium chloride (GdCl_3) were administrated prior to Con A injection. Plasma alanine aminotransferase (ALT), MIP-1α, tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ) levels were determined and histological assessment of the liver was performed

Denatured human alpha-defensin attenuates the bactericidal activity and the stability against enzymatic digestion

Elsevier, Tanabe, Hiroki ; Ayabe, Tokiyoshi ; Maemoto, Atsuo ; Ishikawa, Chisato ; Inaba, Yuhei ; Sato, Ryu ; Moriichi, Kentaro ; Okamoto, Kotaro ; Watari, Jiro ; Kono, Toru ; Ashida, Toshifumi ; Kohgo, Yutaka, Biochemical and Biophysical Research Communications, 358(1), 2007, 349-335. authorα-Defensin is an antimicrobial peptide which plays an important role in innate immunity. Human defensin (HD)-5 is stored in the Paneth cells of the small intestine as a pro-form and is cleaved by trypsin, which is co-secreted from the Paneth cell granules. The mature HD-5 is protected from further digestion by the proteolysis enzyme. We generated both recombinant HD-5 and proHD-5, and the reduced form of each peptide in order to determine their physiological roles of the disulfide bonds. The reduced proHD-5 attenuated the bactericidal activity and the stability against the trypsin digestion. Human defensin was protected from the enzymatic degradation by disulfide bridges. We further purified the HD-5 with a disulfide variation in the small intestine of Crohn’s disease patients. The HD-5 was sensitive to the trypsin treatment. These observations evidently predict that a defensin deficiency may be caused by a disulfide disorder in the disease

Vesicovaginal/rectovaginal fistula formation and outcome of Stage IVA carcinoma of the cervix treated with radiotherapy

Purpose: To review the morbidity and mortality of Stage IVA cervical cancer, with a particular focus on the incidence of fistulae. Materials and Methods: The authors retrospectively analyzed 30 patients with Stage IVA cervical cancer, treated with whole pelvic-external beam radiotherapy (WP-EBRT) and high-dose-rate intracavitary brachytherapy (HDR-ICBT). Results: Seven patients presented with vesicovaginal fistula at the time of cancer diagnosis and six developed a fistula during or after radiotherapy (RT). Fistula was diagnosed 0-41 months after cancer diagnosis. The patients with fistulae had a median survival of 32 months. Six patients are alive, four of whom have no evidence of recurrence, while two have persistent disease. The five-year overall survival (OS) was 14.9% in the patients with fistula and was 39.4% in the total series. On multivariate analysis, RT without HDR-ICBT was an independent prognostic factor. Conclusion: High rates of vesicovaginal fistulae were observed in Stage IVA cervical cancer. Interventions for vesicovaginal fistula to improve quality of life are very important