A single immunization with HA DNA vaccine by electroporation induces early protection against H5N1 avian influenza virus challenge in mice

<p>Abstract</p> <p>Background</p> <p>Developing vaccines for the prevention of human infection by H5N1 influenza viruses is an urgent task. DNA vaccines are a novel alternative to conventional vaccines and should contribute to the prophylaxis of emerging H5N1 virus. In this study, we assessed whether a single immunization with plasmid DNA expressing H5N1 hemagglutinin (HA) could provide early protection against lethal challenge in a mouse model.</p> <p>Methods</p> <p>Mice were immunized once with HA DNA at 3, 5, 7 days before a lethal challenge. The survival rate, virus titer in the lungs and change of body weight were assayed to evaluate the protective abilities of the vaccine. To test the humoral immune response induced by HA DNA, serum samples were collected through the eye canthus of mice on various days after immunization and examined for specific antibodies by ELISA and an HI assay. Splenocytes were isolated after the immunization to determine the antigen-specific T-cell response by the ELISPOT assay.</p> <p>Results</p> <p>Challenge experiments revealed that a single immunization of H5N1 virus HA DNA is effective in early protection against lethal homologous virus. Immunological analysis showed that an antigen-specific antibody and T-cell response could be elicited in mice shortly after the immunization. The protective abilities were correlated with the amount of injected DNA and the length of time after vaccination.</p> <p>Conclusion</p> <p>A single immunization of 100 μg H5 HA DNA vaccine combined with electroporation was able to provide early protection in mice against homologous virus infection.</p

Amiloride Enhances Antigen Specific CTL by Faciliting HBV DNA Vaccine Entry into Cells

The induction of relatively weak immunity by DNA vaccines in humans can be largely attributed to the low efficiency of transduction of somatic cells. Although formulation with liposomes has been shown to enhance DNA transduction of cultured cells, little, if any, effect is observed on the transduction of somatic tissues and cells. To improve the rate of transduction, DNA vaccine delivery by gene gun and the recently developed electroporation techniques have been employed. We report here that to circumvent requirement for such equipment, amiloride, a drug that is prescribed for hypertension treatment, can accelerate plasmid entry into antigen presenting cells (APCs) both in vitro and in vivo. The combination induced APCs more dramatically in both maturation and cytokine secretion. Amiloride enhanced development of full CD8 cytolytic function including induction of high levels of antigen specific CTL and expression of IFN-γ+perforin+granzymeB+ in CD8+ T cells. Thus, amiloride is a facilitator for DNA transduction into host cells which in turn enhances the efficiency of the immune responses

Dendritic Cells Transfected with scFv from Mab 7.B12 Mimicking Original Antigen gp43 Induces Protection against Experimental Paracoccidioidomycosis

Paracoccidioidomycosis (PCM), endemic in Latin America, is a progressive systemic mycosis caused by Paracoccidioides brasiliensis (P. brasiliensis), which primarily attacks lung tissue. Dendritic cells (DCs) are able to initiate a response in naïve T cells, and they also participate in Th-cell education. Furthermore, these cells have been used for therapy in several disease models. Here we transfected DCs with a plasmid (pMAC/PS-scFv) encoding a single chain variable fragment (scFv) of an anti-Id antibody that is capable of mimicking gp43, the main antigenic component of P. brasiliensis. First, Balb/c mice were immunized subcutaneously with pMAC/PS-scFv and, after seven days, scFv protein was presented to the regional lymph nodes cells. Moreover, we showed that the DCs transfected with scFv were capable of efficiently activating proliferation of total lymph node cells and inducing a decrease in lung infection. Therefore, our results suggested that the use of scFv-transfected DCs may be a promising therapy in the paracoccidioidomycosis (PCM) model

Different T helper cell types and antibody isotypes generated by saline and gene gun DNA immunization.

Abstract Several routes and methods of DNA immunization have been shown to generate Ab, Th cells, and CTL responses. However, few studies have directly compared the immune responses generated by different routes and methods of DNA immunization. Utilizing an influenza hemagglutinin (H1)-expressing plasmid, we compared the immune response produced by saline injection of DNA into skin or muscle, and gene gun immunization of skin or muscle. We found that saline-DNA immunization raised a predominantly Th1 response with mostly IgG2a anti-H1 Ab, while gene gun DNA immunization produced a predominantly Th2 response with mostly IgG1 anti-H1 Abs. These distinct types of immune responses were generated by the method, not the route, of DNA immunization. The initial immunization established the Th cell-type of the immune response. The Th cell-type did not change with further DNA immunizations by the same or the alternate method, or after a viral challenge. The ability to generate different Th types was not due to differences in the doses of DNA used in saline and gene gun DNA immunization. These findings have important implications for vaccine design and studies of the mechanism of Th cell differentiation.</jats:p

A phase I study of BMS-582664 (brivanib alaninate), an oral dual inhibitor of VEGFR and FGFR tyrosine kinases, in combination with full-dose cetuximab in patients (pts) with advanced gastrointestinal malignancies (AGM) who failed prior therapy

14018 Background: Brivanib is an oral prodrug of BMS-540215, a dual tyrosine kinase inhibitor of VEGFR and FGFR signaling. Prior studies have validated both VEGF and EGF signaling pathways as targets in AGM. The MTD of single-agent brivanib is 800 mg qd (ASCO #3051, 2006). Methods: An open-label Phase I dose-escalation study of brivanib in combination with cetuximab was conducted in pts with AGM who failed prior therapy. Brivanib was given po Day 1 and qd from Day 8, starting at 320 mg. Cetuximab was given IV Day 8 (400 mg/m2) then weekly (250 mg/m2). Dose escalation of brivanib continued to 800 mg qd, when an expansion cohort for pts with colorectal cancer (CRC) was opened for additional safety and efficacy. Fresh tissue and blood sampling for biomarker and pharmacokinetic (PK) analysis was performed. FDG-PET was obtained at Baseline X 2, Days 15 and 56. Tumor response (modified WHO) was evaluated q 8 weeks. Results: 18 pts (15 CRC, 2 esophageal, 1 other) were treated with 320, 600 or 800 mg qd of brivanib in combination with cetuximab for a median of 8 weeks (range 1 - 20+). A single DLT, bilateral pulmonary emboli, occurred at 320 mg qd. Few treatment-related AEs occurred across the 3 cohorts (Table). PK/biomarker data is pending. Available FDG-PET results from measurements in 8 pts with 2–3 target lesions showed good baseline reproducibility in SUVpeak, SUVmean and SUVmax, with intra-subject CV of 3.6%, 7.2% and 9.3%, respectively. Conclusions: Brivanib in combination with full-dose cetuximab was well tolerated at ≤800 mg qd and did not result in enhancement of cetuximab associated AEs. Pre-treatment FDG-PET is a highly reproducible imaging modality. [Table: see text] [Table: see text] </jats:p