A highly optimized DNA vaccine confers complete protective immunity against high-dose lethal lymphocytic choriomeningitis virus challenge.
ABSTRACT Protection against infection is the hallmark of immunity and the basis of effective vaccination. For a variety of reasons there is a great demand to develop new, safer and more effective vaccine platforms. In this regard, while 'first-generation' DNA vaccines were poorly immunogenic, new genetic 'optimization' strategies and the application of in vivo electroporation (EP) have dramatically boosted their potency. We developed a highly optimized plasmid DNA vaccine that expresses the lymphocytic choriomeningitis virus (LCMV) nucleocapsid protein (NP) and evaluated it using the LCMV challenge model, a gold standard for studying infection and immunity. When administered intramuscularly with EP, robust NP-specific cellular and humoral immune responses were elicited, the magnitudes of which approached those following acute LCMV infection. Furthermore, these responses were capable of providing 100% protection against a high-dose, normally lethal virus challenge. This is the first non-infectious vaccine conferring complete protective immunity up to 8 weeks after vaccination and demonstrates the potential of 'next-generation' DNA vaccines.
Article: Delivery of multiple epitopes by recombinant detoxified adenylate cyclase of Bordetella pertussis induces protective antiviral immunity.[show abstract] [hide abstract]
ABSTRACT: CyaA, the adenylate cyclase toxin from Bordetella pertussis, can deliver its N-terminal catalytic domain into the cytosol of a large number of eukaryotic cells and particularly into professional antigen-presenting cells. We have previously identified within the primary structure of CyaA several permissive sites at which insertion of peptides does not alter the ability of the toxin to enter cells. This property has been exploited to design recombinant CyaA toxoids capable of delivering major histocompatibility complex (MHC) class I-restricted CD8(+) T-cell epitopes into antigen-presenting cells and to induce specific CD8(+) cytotoxic T-lymphocyte (CTL) responses in vivo. Here we have explored the capacity of the CyaA vector carrying several different CD8(+) T-cell epitopes to prime multiple CTL responses. The model vaccine consisted of a polyepitope made of three CTL epitopes from lymphocytic choriomeningitis virus (LCMV), the V3 region of human immunodeficiency virus gp120, and chicken ovalbumin, inserted at three different sites of the catalytic domain of genetically detoxified CyaA. Each of these epitopes was processed on delivery by CyaA and presented in vitro to specific T-cell hybridomas. Immunization of mice by CyaA toxoids carrying the polyepitope lead to the induction of specific CTL responses for each of the three epitopes, as well as to protection against a lethal viral challenge. Moreover, mice primed against the vector by mock CyaA or a recombinant toxoid were still able to develop strong CTL responses after subsequent immunization with a recombinant CyaA carrying a foreign CD8(+) CTL epitope. These results highlight the potency of the adenylate cyclase vector for induction of protective CTL responses with multiple specificity and/or broad MHC restriction.Journal of Virology 09/2001; 75(16):7330-8. · 5.40 Impact Factor
Article: Transoral resection of axial lesions augmented by intraoperative magnetic resonance imaging. Report of three cases.[show abstract] [hide abstract]
ABSTRACT: Transoral decompression of the cervicomedullary junction may be compromised by a narrow corridor in which surgery is performed, and thus the adequacy of surgical decompression/resection may be difficult to determine. This is problematic as the presence of spinal instrumentation may obscure the accuracy of postoperative radiological assessment, or the patient may require reoperation. The authors describe three patients in whom high-field intraoperative magnetic resonance (MR) images were acquired at various stages during the transoral resection of C-2 disease that had caused craniocervical junction compression. All three patients harbored different lesions involving the cervicomedullary junction: one each of plasmacytoma and metastatic breast carcinoma involving the odontoid process and C-2 vertebral body, and basilar invagination with a Chiari I malformation. All patients presented with progressive myelopathy. Surgical planning MR imaging studies performed after the induction of anesthesia demonstrated the lesion and its relationship to the planned surgical corridor. Transoral exposure was achieved through placement of a Crockard retractor system. In one case the soft palate was divided. Interdissection MR imaging revealed that adequate decompression had been achieved in all cases. The two patients with carcinoma required placement of posterior instrumentation for stabilization. Planned suboccipital decompression and placement of instrumentation were averted in the third case as the intraoperative MR images demonstrated that excellent decompression had been achieved. Intraoperatively acquired MR images were instrumental in determining the adequacy of the decompressive surgery. In one of the three cases, examination of the images led the authors to change the planned surgical procedure. Importantly, the acquisition of intraoperative MR images did not adversely affect operating time or neurosurgical techniques, including instrumentation requirements.Journal of Neurosurgery 11/2001; 95(2 Suppl):239-42. · 2.96 Impact Factor