HUMAN PAPILLOMA VIRUS Training Program in the Immunobiology of Vaccines
This is a training grant funded by NIH in support of three postdoctoral trainees.
Training will emphasize principles crucial for design of vaccines for prevention of infectious diseases, treatment of cancer and autoimmunity and prevention of unwanted immunity in gene therapy. The major emphasis of training will be on laboratory work under the supervision of one of the trainers. This training will be supplemented with a bench course in techniques relevant for state of the art vaccine development, a didactic course on novel types of vaccines and clinical vaccine development, a course in proper scientific conduct, discussion groups and seminars. The training faculty is composed of faculty from The Wistar Institute, from The Children's Hospital of Philadelphia, and from the University of Pennsylvania School of Veterinary Medicine and from the University of Pennsylvania Medical School. The trainers are from diversified backgrounds such as cellular immunology, autoimmunity, parasitology, virology, viral immunology, molecular biology, structural biology and gene therapy with a shared interest in vaccine development thus offering a multidisciplinary approach that is focused on the immunobiology of vaccines.

DNA Vaccines - Responses to Vectors with Rabies Antigen
This grant, funded by NIH, aims at improving the efficacy of DNA vaccines to rabies virus by using chemokine adjuvants and alternate promoters. The 1st goal is to develop an improved vaccine to rabies virus that provides protection against a severe form of inhalation challenge such as with weaponzied rabies virus upon a single dose given orally. We have developed E1-deleted adenoviral recombinants derived from chimpanzee isolates. Chimpanzee (chimp) adenoviruses (Ad) such as that of the C68 serotype, which has been the focus of our studies do not circulate in the human population and virus neutralizing antibodies (VNAs) to common human serotypes of Ad fail to cross-react with the chimp serotypes. Chimp Ad vaccines are thus not impaired by natural exposure of a human population to most common human serotypes of Ad. The 2nd goal is to develop additional vaccine carriers using the rabies virus glycoprotein as the model antigen. Ad recombinants of non-human serotypes can only be used once as vaccine carriers. The ensuing vaccine carrier-specific VNA response prohibits repeated use of the same carrier for additional antigens. Considering the unsurpassed efficacy of E1-deleted Ad recombinants in inducing transgene product-specific immune responses, a trait that is shared by the human and chimp serotypes that have been tested thus far, development of additonal chimp Ad serotypes as vaccine vectors is warranted

HIV-1 Vaccine Based on Chimp Serotypes of Adenovirus
This research, funded by NIH, aims to test adenoviral recombinants based on simian serotypes for induction of immune responses to gag/pol/rev of HIV-1 or SIV-1 in a mouse model. Its goal is the development and characterization of novel vaccine carriers to HIV-1 antigens based on El-deleted adenoviral recombinants derived from chimpanzee serotypes in pre-clinical animal models. Such serotypes of adenovirus do not circulate in the human population. They should induce responses to the HIV-1 antigens that are unimpaired by pre-existing neutralizing antibodies to the vaccine carrier. Such antibodies are expected to reduce the efficacy of vaccines based on common human serotypes of adenovirus in a human target population.

Genetic Vaccine to Rabies Virus
This grant, funded by NIH, aims to develop an improved rabies virus vaccine for post-exposure treatment. The focus of this application is to develop an adenovirus-based vaccine against rabies virus that can provide rapid immunity following a single administration in response to a bioterrorism attack. The vaccines to be evaluated are based on an E1-deleted simian adenoviral vector derived from a chimpanzee isolate. In animal models, E1-deleted human adenoviral recombinants of the serotype 5 (AdHu5) have shown high efficacy as vaccine carriers. Humans are infected by common serotypes of human adenovirus such as AdHu5 and a significant percentage has neutralizing antibodies to this serotypes, which impair the efficacy of AdHu5 based vaccines. To circumvent this problem, novel replication-defective adenoviral vaccine carriers based on El-deleted recombinants of chimpanzee-derived adenoviruses were developed. These viruses do not circulate in the human population and fail to carry neutralizing B cell epitopes that cross-react with the common serotypes of human adenoviruses. Lack of preexisting virus-neutralizing antibodies in the human population suggests that these novel adenoviral recombinants may provide improved vaccine carriers for use in humans. A simian adenoviral vector termed adenovirus C68 (AdC68) was generated as a molecular clone to express the glycoprotein of rabies virus. In mice, this vector induced after a single dose complete protection to rabies virus challenge.

Oral Vaccine to Inhalation Rabies
The research on this grant is designed to develop an improved vaccine to rabies virus that provides protection upon a single dose given orally or intranasally against a severe form of inhalation challenge such as with weaponized rabies virus. We have developed an El-deleted adenoviral recombinant derived from a chimpanzee isolate. These adenoviruses (Ad) of the C68 serotype (AdC68) does not circulate in the human population and virus neutralizing antibodies (VNAs) to common human serotypes of Ad fail to cross-react with AdC68 virus. Vaccines based on AdC68 virus, such as the one expressing the rabies virus glycoprotein (AdC68rab.gp) are thus not impaired by natural exposure of a human population to most common human serotypes of Ad. The biodistribution of the AdC68rab.gp vaccine upon oral and intranasal application into mice will be tested. It will be established if oral or intranasal immunization with the AdC68rab.gp vaccine protects against inhalation rabies and which immune effect mechanisms (serum or mucosal VNAs or frequencies of rabies virus specific B cells in nasal associated lymphoid tissues, spleens or lungs) correlate with protection. The longevity of vaccine-induced protection will be determined. Efficacy of the mucosal vaccine will be assessed in immunologically challenged animals such as infant or aged mice and mice lacking CD4+ T cells. The AdC68rab.gp vaccine will be tested in a non-human primate rabies virus challenge model.

Immune Responses to AAV-Mediated FIX Gene Transfer
The goal of this application is to further characterize immune responses that can cause the elimination of recombinant adeno-associated virus (rAAV) transduced cells. Most humans are naturally exposed to AAV-2 together with a helper virus and thus have immunological memory to AAV-2. Memory T cells can be triggered more readily than naive lymphocytes, which was not taken into account by pre-clinical animal experiments conducted thus far. Concerns about immunological consequences of rAAV-mediated gene transfer were substantiated by the outcome of a clinical trial in which human hemophilia B patients were infused into the liver with rAAV-2-F.IX vectors. Only one patient achieved therapeutic levels of F.IX, which were sustained for 4 weeks and then started to decline. At the same time the patient developed a transaminitis, which resolved after F.IX levels decreased to baseline levels. Overall, the patient's clinical course was compatible with immune-mediated destruction of rAAV-transduced hepatocytes. Additional data generated since substantiated our hypothesis that AAV-2-specific T cells induced by a natural infection can cause elimination of rAAV-transduced hepatocytes. To further define immune responses to AAV and rAAV-encoded transgenes under conditions thai mimic those of human hemophilia patients and to then devise informed strategies to circumvent such problems we are proposing 4 interlinked Projects supported by 2 Cores. Project 1 will define T cell responses to AAV capsid proteins in humans and in non-human primates and assess their effect on hepatic rAAV-mediated gene transfer. Project 2 will elucidate the effect of pre-existing AAV-2-specific T cell-mediated immunity on hepatic rAAV vector-mediated gene transfer in mice. Project 3 will define regulatory immune responses that prevent induction of CD8+ T cell responses to a rAAV-encoded transgene product. Project 4 will focus on the potential use of regulatory T cells to ablate unwanted immune responses to rAAV-mediated gene transfer.

An Improved Influenza A Vaccine for Rapid Protection of the Elderly
This research, funded by NIH, proposes to develop an influenza vaccine based on adjuvanted simian adenoviral vectors that provides protection through the induction of T cell-mediated immunity