Cardiac Safety of Modified Vaccinia Ankara for Vaccination against Smallpox in a Young,Healthy Study Population

Background

Conventional smallpox vaccines based on replicating vaccinia virus (VV) strains (e.g. Lister Elstree, NYCBOH) are associated with a high incidence of myo-/pericarditis, a severe inflammatory cardiac complication. A new smallpox vaccine candidate based on a non-replicating Modified Vaccinia Ankara (MVA) poxvirus has been assessed for cardiac safety in a large placebo-controlled clinical trial.

Methods

Cardiac safety of one and two doses of MVA compared to placebo was assessed in 745 healthy subjects. Vaccinia-naïve subjects received either one dose of MVA and one dose of placebo, two doses of MVA, or two doses of placebo by subcutaneous injection four weeks apart; vaccinia-experienced subjects received a single dose of MVA. Solicited and unsolicited adverse events (AE) and cardiac safety parameters (recorded as Adverse Events of Special Interest, AESI) were monitored after each injection.

Results

A total of 5 possibly related AESI (3 cases of palpitations, 2 of tachycardia) were reported during the study. No case of myo- or pericarditis occurred. One possibly related serious AE (SAE) was reported during the 6-month follow-up period (sarcoidosis). The most frequently observed AEs were injection site reactions.

Conclusions

Vaccination with MVA was safe and well tolerated and did not increase the risk for development of myo-/pericarditis.

Trial Registration

ClinicalTrials.gov NCT00316524     

Dynamic assessment of cell viability,proliferation and migration using real time cell analyzer system (RTCA)

Cell viability and cell migration capacities are critical parameters for cell culture-related studies. It is essential to monitor the dynamic changes of cell properties under various co-culture conditions to our better understanding of their behaviours and characteristics. The real time cell analyzer (RTCA, xCELLigence, Roche) is an impedance-based technology that can be used for label-free and real-time monitoring of cell properties, such as cell adherence, proliferation, migration and cytotoxicity. The practicality of this system has been proven in our recent cancer studies. In the present method, we intend to use co-cultures of pancreatic cancer cells (HP62) and mesenchymal stem cells to describe in detail, the procedures and benefits of RTCA.     

Virulence of a South African isolate of the <Emphasis Type="Italic">Cryptophlebia leucotreta</Emphasis> granulovirus to <Emphasis Type="Italic">Thaumatotibia leucotreta</Emphasis> neonate larvae

Surface inoculation dose–response and time–response bioassays and detached fruit bioassays were conducted with a novel South African isolate of the Cryptophlebia leucotreta granulovirus (CrleGV-SA) against Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Noctuidae) neonate larvae. LC₅₀ and LC₉₀ values were estimated to be 4.095 × 10³ and 1.185 × 10⁵ OBs ml⁻¹, respectively. LT₅₀ and LT₉₀ values were estimated to be 4 days 22 h and 7 days 8 h, respectively, categorising the virus as a fast or type 2 granulovirus. There was a conspicuous difference in behaviour between larvae on inoculated diet and untreated diet, resulting in a significant reduction in penetration of diet. Bioassays on detached Navel oranges revealed LC₅₀ and LC₉₀ values of 9.310 × 10⁷ and 1.515 × 10⁹ OBs ml⁻¹, when using data on numbers of larvae per fruit rather than on numbers of infested fruit. Field trials will be conducted.     

Fibroblast populated collagen matrix promotes islet survival and reduces the number of islets required for diabetes reversal

Islet transplantation represents a viable treatment for type 1 diabetes. However, due to loss of substantial mass of islets early after transplantation, islets from two or more donors are required to achieve insulin independence. Islet-extracellular matrix disengagement, which occurs during islet isolation process, leads to subsequent islet cell apoptosis and is an important contributing factor to early islet loss. In this study, we developed a fibroblast populated collagen matrix (FPCM) as a novel scaffold to improve islet cell viability and function post-transplantation. FPCM was developed by embedding fibroblasts within type-I collagen and used as scaffold for islet grafts. Viability and insulin secretory function of islets embedded within FPCM was evaluated in vitro and in a syngeneic murine islet transplantation model. Islets embedded within acellular matrix or naked islets were used as control. Islet cell survival and function was markedly improved particularly after embedding within FPCM. The composite scaffold significantly promoted islet isograft survival and reduced the critical islet mass required for diabetes reversal by half (from 200 to 100 islets per recipient). Fibroblast embedded within FPCM produced fibronectin and growth factors and induced islet cell proliferation. No evidence of fibroblast over-growth within composite grafts was noticed. These results confirm that FPCM significantly promotes islet viability and functionality, enhances engraftment of islet grafts and decreases the critical islet mass needed to reverse hyperglycemia. This promising finding offers a new approach to reducing the number of islet donors per recipient and improving islet transplant outcome.     

B7-H4 Treatment of T Cells Inhibits ERK, JNK, p38, and AKT Activation

B7-H4 is a newly identified B7 homolog that plays an important role in maintaining T-cell homeostasis by inhibiting T-cell proliferation and lymphokine-secretion. In this study, we investigated the signal transduction pathways inhibited by B7-H4 engagement in mouse T cells. We found that treatment of CD3(+) T cells with a B7-H4.Ig fusion protein inhibits anti-CD3 elicited T-cell receptor (TCR)/CD28 signaling events, including phosphorylation of the MAP kinases, ERK, p38, and JNK. B7-H4.Ig treatment also inhibited the phosphorylation of AKT kinase and impaired its kinase activity as assessed by the phosphorylation of its endogenous substrate GSK-3. Expression of IL-2 is also reduced by B7-H4. In contrast, the phosphorylation state of the TCR proximal tyrosine kinases ZAP70 and lymphocyte-specific protein tyrosine kinase (LCK) are not affected by B7-H4 ligation. These results indicate that B7-H4 inhibits T-cell proliferation and IL-2 production through interfering with activation of ERK, JNK, and AKT, but not of ZAP70 or LCK.     

Tumor Xenograft Response to Redox-Active Therapies Assessed by Magnetic Resonance Imaging Using a Thiol-Bearing DOTA Complex of Gadolinium

Gd-LC6-SH is a thiol-bearing DOTA complex of gadolinium designed to bind plasma albumin at the conserved Cys(34) site. The binding of Gd-LC6-SH shows sensitivity to the presence of competing thiols. We hypothesized that Gd-LC6-SH could provide magnetic resonance imaging (MRI) enhancement that is sensitive to tumor redox state and that the prolonged retention of albumin-bound Gd-LC6-SH in vivo can be exploited to identify a saturating dose above which the shortening of MRI longitudinal relaxation time (T(1)) of tissue is insensitive to the injected gadolinium dose. In the Mia-PaCa-2 pancreatic tumor xenograft model in SCID mice, both the small-molecule Gd-DTPA-BMA and the macromolecule Galbumin MRI contrast agents produced dose-dependent decreases in tumor T(1). By contrast, the decreases in tumor T(1) provided by Gd-LC6-SH at 0.05 and 0.1 mmol/kg were not significantly different at longer times after injection. SCID mice bearing Mia-PaCa-2 or NCI-N87 tumor xenografts were treated with either the glutathione synthesis inhibitor buthionine sulfoximine or the thiol-oxidizing anticancer drug Imexon, respectively. In both models, there was a significantly greater increase in tumor R(1) (=1/T(1)) 60 minutes after injection of Gd-LC6-SH in drug-treated animals relative to saline-treated controls. In addition, Mercury Orange staining for nonprotein sulfhydryls was significantly decreased by drug treatment relative to controls in both tumor models. In summary, these studies show that thiol-bearing complexes of gadolinium such as Gd-LC6-SH can serve as redox-sensitive MRI contrast agents for detecting differences in tumor redox status and can be used to evaluate the effects of redox-active drugs.